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August 14

Squiggly rain drops

I took a picture of the rain outside my window. It was both raining and sunny outside, so I thought that the raindrops would show up in the picture. They did, but they show up as squiggly lines. What is going on here? I took this shot through a window with a basic UV filter on. Camera settings: 1/90s, f5.6, 400 ISO. Any ideas? You will have to zoom into the picture to see the weird effect.

Dlempa squiggly

— Preceding unsigned comment added by Dlempa (talk • contribs) 00:31, 14 August 2012 (UTC)

They're lines because the shutter speed was too slow to "freeze" them. Since the squiggles are all the same shape, the squggliness is presumably the result of camera movement during the exposure. Deor (talk) 00:41, 14 August 2012 (UTC)

That's actually a pretty cool photo and I 100% agree with the above answer. Vespine (talk) 01:47, 14 August 2012 (UTC)

You see this effect very often in WWII era dogfight videos, such as here. The video in general may seem only mildly jerky, but the tracer bullets follow seemingly wild, zig-zagging trajectories. Someguy1221 (talk) 01:53, 14 August 2012 (UTC)

I suggest you use a timer and a stand, to prevent any hand shaking effect. Of course, the camera's own shutter motion might still cause some vibration. You also need a faster shutter speed, but that might make it too dark, so you will need to compensate for that. StuRat (talk) 01:58, 14 August 2012 (UTC)

I'd expect the circular part of the lines to be due to the shutter movement. An outside force wouldn't be so symmetric or return the camera to it's original position. Interesting to see Ssscienccce (talk) 02:07, 14 August 2012 (UTC)

But that circular motion occurs in the middle of each rain drop's motion. Wouldn't shutter motion be expected at the start and end, not in the middle ? StuRat (talk) 02:26, 14 August 2012 (UTC)

Yes, I'm wondering what mechanism could best explain the effect. First idea was focal plane shutters with two moving curtains, the slowing down of the first one and speeding up of the second; but that would show other differences I think. A digital camera can control shutter time electronically without the need for a physical shutter, it could be due to any kind of spring or electromagnet activated movement occuring during the exposure. it just seems too "perfect" to be due to hand movement. But that's just my opinion. Ssscienccce (talk) 04:04, 14 August 2012 (UTC)

I think that this sort of picture is one in which a slower shutter speed would actually produce a more interesting result (if the camera tremor could be eliminated). If the shutter was so fast as to show dotlike drops, they would be basically indistinguishable from dust specks or other flaws in the photograph. Even to the naked eye, falling raindrops look rather more elongated than the ones in the photo, raising the question of what the "shutter speed" of the human eye is. Deor (talk) 02:38, 14 August 2012 (UTC)

@ Sturat, the transmission of the shutter shock to the camera's 'retina' moves at the speed of sound in the camera body, while the light moves at the speed of light. It is not inconceivable that the shock would show up in the image after the image was already partially formed. μηδείς (talk) 04:49, 14 August 2012 (UTC)

Well it would be if the "retina" ie the film reacted instantaneously, but it doesn't. Taking the camera body as an aluminium alloy (speed of sound ~6500 m/s) and the distance from shutter to film as 20 mm, the time taken for shutter reaction to reach the film is of the order 3 microseconds. Time taken for the light, velocity of propagation 300,000,000 m/s, distance 20 mm, the time taken is ~7 picoseconds. Yep, light is darn fast compared to sound. BUT, the exposure time was 1/90 = 11 milliseconds. The nature of film is that the film exposure reaction is sensibly proportional to duration throughout this time. Typically, the shutter will take 1/3 the time to open, and 1/3 the time to close, ie ~3 milliseconds. So, the mechanical delay after the light is about 1/1000th of the shutter opening time, and about 1/3000th of the film exposure time. Clearly the the mechanical delay (and light delay) of of shutter rebound is negligible compared to image formation time - the film has been exposed less than 0.1% by the time the mechanical impulse arrives. The assumptions I've made about distances, shutter opening times etc are very rough, but it is inconceivable that they could be out by a factor of 1000x. Shutter rebound can only affect images by imparting an acceleration to the whole camera (camera sensibly a rigid body) with respect to the scene. Ratbone121.221.30.70 (talk) 05:38, 14 August 2012 (UTC)

Another part of the effect may be the fact that the sensor in your camera is scanned sequentially. There are some great pictures online of aircraft props taken with iPhones where the prop takes all sorts of interesting forms because it rotated through the lines of pixels as they were scanned. 209.131.76.183 (talk) 11:46, 14 August 2012 (UTC)

Thanks all for the comments and help! I guess I will continue to experiment. dlempa (talk) 14:53, 14 August 2012 (UTC)

What is the difference between a "larvae" and a "Nymph"?

What is the difference between a "larvae" and a "Nymph"? http://en.wikipedia.org/wiki/Special:Contributions/175.140.180.186

See the second and third sentences of Nymph (biology). Larvae, by the way is plural; it's "a larva", not "a larvae". Deor (talk) 02:42, 14 August 2012 (UTC)

Simply the mode of development. Nymphs undergo incomplete metamorphosis (hemimetabolism), while larvae undergo complete metamorphosis (holometabolism). Both are the juvenile stages of insects between egg and adult.

In nymphs, the growth of the juvenile stages is by gradual acquisition of features of the imago. For example, the first instar may already possess all the features of the adults, except the wings and the ability to produce sperm or eggs. Each successive molt and instar produces larger individuals and the beginnings of wings until the final molt when the imago finally emerges with fully developed wings and full sexual maturity. Note that hemimetabolic insects may also have a stage known as the "prolarva" or "pronymph", which is basically just an advanced embryo. This stage may occur inside the egg, though in some it may actually hatch as prolarva before undergoing their first molt and becoming the first instar nymph. But this time period of a prolarva outside the egg is usually very very short, lasting only a few seconds to a few minutes. The development through nymphs is believed to be the ancestral state in insects.

In larvae, in contrast, the adult features are more or less kept in an embryonic state. They often look like completely different organisms from their adult forms, with very different behavior. They also go through a stage missing in hemimetabolic insects - pupation - where the change from larva to imago is fast-forwarded. It has been hypothesized that this evolved sometime during the early Carboniferous due to the development of eggs with unusually small amounts of food reserves, thus necessitating restriction of growth and requiring the larvae to gather the resources for its final growth on its own. It is also generally accepted (the so-called "pronymph hypothesis") that holometabolic larvae are homologous to hemimetabolic prolarvae (i.e. it's an extended version of the prolarval/pronymphal stage in insects which undergo incomplete metamorphosis).

This is assuming that you're speaking solely about insects. As other animals also use those terms and others differently. Fish young, for example, are also called "larvae", while cephalopod young are called "paralarvae". Ticks, which are arachnids, actually have both larval and nymphal stages, though not in the same sense as in insects as their larvae are just miniature versions of their adults.-- OBSIDIAN†SOUL 03:38, 14 August 2012 (UTC)

A nymph that lives in a tree is a lot cuter than larvae that live in a tree: [1]. StuRat (talk) 04:30, 14 August 2012 (UTC)

You do realize that termites do not undergo pupation, and have nymphs, not larvae? Nonetheless, larvae are less attractive than nymphs. μηδείς (talk) 04:44, 14 August 2012 (UTC)

Higgs field vs. Dark Energy

What is the relationship between the Higgs field and Dark Energy? Would these balance off against each other to reduce the predicted Cosmological constant to its observed value? Hcobb (talk) 02:47, 14 August 2012 (UTC)

Both can be explained with scalar fields, although dark energy doesn't require a particle, just a uniform potential as a physical property of spacetime (which is technically much simpler than a scalar field, but similar to the scalar fields used to explain cosmic inflation and the metric expansion of space.) Which predicted cosmological constant are you referring to? 75.166.207.214 (talk) 08:07, 14 August 2012 (UTC)

I'm attempting to explain the Vacuum catastrophe. Universe starts tiny and empty and then zero-point energy causes Inflation (cosmology) until the Electroweak symmetry breaking limit is reached. At that point a uniform field of Higgs bosons almost pushes through to carpet the universe wall to wall, but is just slightly overmatched by the zero-point energy and the result of the cancellation is the very tiny amount of Dark energy that we see today. Hcobb (talk) 15:31, 14 August 2012 (UTC)

The Higgs condensate contributes to the zero-point energy, so what you're proposing is really vacuum energy from the Higgs vs. other vacuum energy and cosmological constant. There's an interesting paper from 1980 by Kolb and Wolfram [2] in which they suggest that the vacuum energy of the Higgs condensate could be used to cancel out a cosmological constant; your suggestion goes along very similar lines. However, the famous factor-of-10^120 discrepancy is dominated by other fields, and the Higgs contribution is much too small to make a big difference. It generally makes things slightly worse. Even if you did manage to balance one large contribution against another to get a very small residual vacuum energy, you've only converted the matter into a terrible fine-tuning problem. The real problem is that we don't know how to calculate the vacuum energy even in a well-studied model like the standard one. --Amble (talk) 15:47, 14 August 2012 (UTC)

Please identify this pill

One side: G mark or something looking like an on/off button in an almost full circle.

Other side: ML 10 written on two lines.

Size: 5 mm in diameter and 3 mm in width.

Picture link - 1: [URL=http://picturepush.com/public/8971010][IMG]http://www2.picturepush.com/photo/a/8971010/img/8971010.jpg[/IMG][/URL]

[url=http://picturepush.com/public/8971088][img=http://www5.picturepush.com/photo/a/8971088/img/8971088.jpg][/url]

Additional information: The pill was found in my car - After it had been to Hamburg and also after I had been to a festival. It might have been one of my friends that have lost it.

I am pretty sure it's not one of these (Medication my dad is taking) :

zolpidem hexal venlafaxin orifarm furix digoxindak kaleorid tolmin delepsine retard litiumkarbonat oba — Preceding unsigned comment added by Azalin (talk • contribs) 08:58, 14 August 2012 (UTC)

Only one way to find out. GC-MS it. 203.27.72.5 (talk) 09:03, 14 August 2012 (UTC)

If you're pretty sure it's something illicit, you could get a kit from DanceSafe or a similar organisation, or alternatively send it to EcstasyData.org or similar for testing. 203.27.72.5 (talk) 09:10, 14 August 2012 (UTC)

Is it by any chance a hexagonal G ? (It would help to have a picture of that side, too). I found two round, white pills with hexagonal G's alone on one side: donepezil and voriconazole. Here's a 2 page list of those two and 16 other meds with a regular G alone on one side of a white, round pill: [3]. However, none of them matches the "ML 10" on the other side. StuRat (talk) 09:14, 14 August 2012 (UTC)

That G is the one used by Alphapharm on their tablets, and from their other tablets the 10 will mean 10mg. The product could well be Lumin or mianserin, an antidepressant, which is marked with MI.[4] Graeme Bartlett (talk) 10:15, 14 August 2012 (UTC)

Sure looks like it: right link this time.. Ssscienccce (talk) 12:22, 14 August 2012 (UTC) oops.. fixed link Ssscienccce (talk) 15:26, 14 August 2012 (UTC)

Thanks a lot for the help - I believe it's either my Dad who lost it out of his pocket or in worst case - a friend having a depression - I wonder if that pill could be used as a recreational pill. — Preceding unsigned comment added by Azalin (talk • contribs) 23:18, 15 August 2012 (UTC)

Ternary mixtures and Raoult law

Considering two binary mixtures, one having negative deviation from Raoult law and the other pozitive deviation, what are the chances that a ternary mixture obtained from the two binaries be almost ideal (no deviation)? --79.119.214.49 (talk) 09:11, 14 August 2012 (UTC)

It's possible, but it's also possible that there will be a larger deviation in either direction. The deviation is governed by pairwise molecular adhesion and cohesion forces, and you are going from two disjoint pairs ((a+b) and (c+d)) to six pairs (a+b, a+c, a+d, b+c, b+d, c+d). I doubt there is a law that says they will always cancel out in aggregate, but molecular behavior is always a surprise one way or another. 75.166.207.214 (talk) 21:09, 14 August 2012 (UTC)

All particles moving at the speed of light

How accurate is it to say that even massive particles move at the speed of light, but because they're constantly bouncing off the higgs field they appear to move slower. Goodbye Galaxy (talk) 14:41, 14 August 2012 (UTC)

The Higgs field is theorised to give particles mass, and it is the fact that they have mass that prevents them travelling at the speed of light (as massless particles, such as photons, do). I don't know if particles "bouncing off" the field is the right way to think about it, though. I don't really understand the Higgs field, but I've never heard it described that way. The particles are interacting with Higgs bosons, and the end result of that is that they travel slower than light, but I don't think it is because they take an indirect path, which is what you are implying. --Tango (talk) 17:32, 14 August 2012 (UTC)

I think it's pretty close. The Higgs interaction that gives mass to the fermions is a three-way interaction between a clockwise circular polarized fermion field, a counterclockwise circular polarized fermion field, and the Higgs field. In order for this to preserve angular momentum the two fermion fields have to be propagating in opposite directions. The two fermion fields by themselves are massless. One way of describing this is that a quantum of energy in one of the fermion fields always moves at the speed of light but keeps switching to the other fermion field, reversing direction in the process, at a rate proportional to the strength of the Higgs interaction. (But the real behavior of the particle is a sum over all histories, including all possible times that that interaction could take place. So you shouldn't think of this back-and-forth motion as happening by clockwork, or at random, but rather in a continuous smoothed-out way.)

The mass of the force bosons (W^± and Z⁰) is more complicated, though, and I don't really understand it. -- BenRG (talk) 18:39, 14 August 2012 (UTC)

It's accurate in a non-rigorous, not-fully-quantum-mechanical picture of how particles behave. A closer analogy is light traveling through water: the light interacts with the water molecules in such a way that it ends up traveling about 1/3 slower than it does through vacuum. The interactions that give mass to a fermion or cause light to travel more slowly through a medium are coherent and continuous. "Bouncing around" could imply discrete scattering events, which would have different effects. --Amble (talk) 19:20, 14 August 2012 (UTC)

Between this subject and "dark matter" and all manner of other exotic things in physics, I'm waiting for science to decide that there is an Aether after all. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:41, 14 August 2012 (UTC)

The Higgs field has only a few practical differences from the traditional luminiferous aether involving Lorentz covariance and that it's a medium for fermion inertia instead of photon propagation, in my opinion, although I'm sure saying so is a serious heresy. 75.166.207.214 (talk) 03:33, 15 August 2012 (UTC)

The Higgs mechanism is not analogous to either light in water or waves in a luminiferous aether. In both of those cases the propagation happens at a fixed speed relative to the rest frame of the medium (water or the aether). Particles that get mass through the Higgs mechanism can move at any sublight speed—all sublight speeds are equivalent in vacuum. It's the particles that don't interact with the Higgs that move at a fixed speed. The nice thing about the back-and-forth explanation of the Higgs mechanism is that it gives a natural reason why you can't exceed c. Everything actually moves at c all the time; you can end up with a slower average speed if you keep changing direction, but you can't end up with a faster average speed. -- BenRG (talk) 05:59, 15 August 2012 (UTC)

Not exactly: the propagation of light in water is dispersive, and photons can be described as having an "effective mass" in a material. But my main point is that the interaction between the light and water, or a particle and the Higgs field, is not like the random scattering interactions suggested by "bouncing off." Instead, you get a propagating mode that's a coherent combination of the two. That's true for light in water and for the Higgs mechanism. The difference is in the details of the dispersion relation. --Amble (talk) 08:37, 15 August 2012 (UTC)

August 15

Proton equilibrium distance?

I was wondering what is the distance between two protons where gravity attraction would be exactly opposite the electromagnetic repulsion force? Or would the distance be so small that the nuclear forces would also have to be taken into account?49.176.68.92 (talk) 02:44, 15 August 2012 (UTC)

A little googling reveals that this is a popular homework question, sorry. 75.166.207.214 (talk) 03:29, 15 August 2012 (UTC)

If it is a homework question, it's a trick one. Both gravity and static electric repulsion fall off at the same rate, being proportional to 1/r². Thus, the electric force is always stronger than the gravitational force. If you were to try to solve this question rigorously, you would find the r such that Gmm/r² = kqq/r², which naturally leads you to Gmm=kqq, which, being untrue, leads to an answer of: Not in this universe, kid. Someguy1221 (talk) 03:43, 15 August 2012 (UTC)

Just to clarify Someguy's correct answer, the equations he uses there are Newton's law of universal gravitation and Coulomb's law. As he noted, the relationship between force and distance for both of these phenomena is the same, which means that the equilibrium is either at zero (gravity is stronger), every distance (both equal each other), or infitinty (electrostatic replusion is stronger which is the case for two protons). In addition to your example of two protons, for any given set of identical particles any one of these three conclusions may hold, but it may never have a unique finite distance where they are at equilibrium. 203.27.72.5 (talk) 04:04, 15 August 2012 (UTC)

The same problem but now take into account the finite Debye length, e.g. consider two protons in the interstellar medium. Count Iblis (talk) 19:40, 15 August 2012 (UTC)

In the intergalactic medium the charge is effectively screened at 10m, so the point where the force due to electrostatic repulsion and gravitation between those two particles cancel out is 10m, but the whole charge screening effect is only there because of the other mobile charge carriers which have turned this into an n-body problem to calculate the point where they actually feel no net force at all. 203.27.72.5 (talk) 20:12, 15 August 2012 (UTC)

Hydrogen isotopes

Why do the hydrogen isotopes ⁵H and ⁶H have longer halflives than ⁴H? This seems to imply that they're more stable. What's causing that stability? 203.27.72.5 (talk) 05:46, 15 August 2012 (UTC)

Several ideas to consider. First, with respect to "more stable", reaction rate depends both on the (in)stability of the components involved and also the difficulty of accomplishing the reaction. It's possible that a reaction is kinetically slow(er than you might think) because it's a more complicated process regardless of how thermodynamically unstable the reactant might be. For example (this is purely my hypothetical for the case at hand) maybe it's simpler to eject a single neutron (decay of ⁴H) than the multiple-neutron decay processes of some other isotopes? Note that the decay-mode(s) column in the table in Isotopes of hydrogen does not exactly match the extended discussion of each isotope earlier in the article. The actual "stability" (intrinsic energy) of the nucleus is directly knowable by looking at the binding energy from the given isotopic masses. Interestingly, ⁴H hits a double-magic number, a fact that gives this isotope more stability and longer half-life than expected by other simple trends. Might be useful to check the references related to the isotopes of interest in the article to see if there is any commentary and to make sure the reported data values actually are correct. DMacks (talk) 07:28, 15 August 2012 (UTC)

If the emission of a single neutron is more kinetically favoured than a multiple emission, then shouldn't the hydrogen-5 and hydrogen-6 decay via single neutron emission to hydrogen-4 and hydrogen-5 respectively just as fast or faster than the hydrogen-4 decays to tritium? The source cited for halflife and decay modes in the extended discussion of ⁴H, ⁵H and ⁶H has some qualifying remarks for ⁵H that I don't understand. It also says that ⁵H only decays via double neutron emission, whereas ⁶H decays via single and triple neutron emission in unknown proportions. This all totally contradicts the table that doesn't cite its source(s) at all, except all of the halflives are in agreement as far as I can see. As for the quality of the source itself, it's an article from Nuclear Physics A, so I imagine it's reasonably authoritative. 203.27.72.5 (talk) 08:05, 15 August 2012 (UTC)

Also, ⁴He is doubly magic, not ⁴H. 203.27.72.5 (talk) 08:16, 15 August 2012 (UTC)

Crap, misread that page...I really need to sleep and/or get more coffee. DMacks (talk) 08:24, 15 August 2012 (UTC)

Given the high stability of ⁴He, it's suprising that ⁴H doesn't emit a beta particle to form that highly stable daughter product, rather than forming a free neutron and tritium, both of which are unstable. The more I look into all of this, the weirder it seems. 203.27.72.5 (talk) 08:22, 15 August 2012 (UTC)

Stellar Transition Paradox?

Suppose one were to accelerate a spacecraft to some appreciable percentage of the speed of light, with respect to some "stationary" reference frame. At some point, an observer in that frame measures the mass of the craft to be just beyond the threshold for stellar ignition. And yet, with respect to the spacecrafts reference frame, there is no tangible increase in mass. Obviously, the craft cannot transform into a star in one reference frame and remain unchanged in another. So what am I missing here? — Preceding unsigned comment added by 66.87.126.39 (talk) 06:32, 15 August 2012 (UTC)

That it's a (potential) star's rest mass which much exceed the ignition mass threshold for it to fire up ? StuRat (talk) 06:36, 15 August 2012 (UTC)

That's incorrect. Gravitation is a function of mass-energy, and it's the gravitation that compresses the core to initiate fusion. 203.27.72.5 (talk) 06:43, 15 August 2012 (UTC)

Self-gravitation, which is what is relevant for stellar ignition, is a function of mass-energy in the rest frame of the object in question. If you are interested in the gravity felt by the observer, then it is more complicated, but if you want the gravity felt by one part of the spacecraft due to another part of the spacecraft, with both parts moving together, then it is all nice and simple. --Tango (talk) 12:10, 15 August 2012 (UTC)

(edit conflict)How would they measure the mass? The whole idea of relativistic mass is deprecated by experts because it is so easy to misunderstand. Dbfirs 06:40, 15 August 2012 (UTC)

For an explanation of the difference between rest mass and relativistic mass, which as explained above is the key issue here, see Mass in special relativity. Red Act (talk) 15:29, 15 August 2012 (UTC)

Okay, so an increase in relativistic mass would only equate to a higher energy content in the system relative to the observer, but not, say, it's gravitational force. Is that correct? — Preceding unsigned comment added by 66.87.127.160 (talk) 16:08, 15 August 2012 (UTC)

In general, it doesn't even make sense to ask by what factor the gravitational force produced by a body changes if the body is rapidly moving, for a couple reasons:

First of all, Newtonian gravity doesn't in general give the right answers when dealing with very rapidly moving objects, even if you try to make special relativistic corrections to Newtonian gravity. Instead, you in general need to use general relativity. And in general relativity, gravity isn't even a force (i.e., gravity isn't something that produces a proper acceleration), although it can be treated locally as a fictitious force. See Fictitious force#Gravity as a fictitious force.

Secondly, force is a vector quantity, not a scalar, and all components of a force do not in general transform identically under a Lorentz transformation.

You also have to be careful about what you're expecting force to mean about a relativistic system, because unless an object's acceleration is orthogonal to its velocity, the equation f=ma, with f and a being three-dimensional vectors, does not in general hold, regardless of whether m is the rest mass or the relativistic mass. Instead, what does hold in general is F=mA, with F the four-force, m the rest mass, and A the four-acceleration. m being the rest mass in F=mA is one of the reasons why rest mass is a more useful concept than relativistic mass.

Despite the above caveats, it does become possible to meaningfully answer your question if you make some simplifying assumptions: Assume that object 1 and object 2 are moving slowly relative to each other, and assume that in the “lab” frame, at some instant of interest object 1 and object 2 are at the same x coordinate, and are moving in precisely the x direction at the same huge velocity. In that case, even though the relativistic mass of object 1 is larger than its rest mass by a factor of γ, the force that it exerts on object 2 is actually smaller as measured in the lab frame than in the objects' rest frame, by a factor of 1/γ. The three-dimensional equation f=ma does hold in the lab frame in this situation, with m being object 2's relativistic mass, which implies that object 2's acceleration is smaller as measured in the lab frame than in the objects' rest frame by a factor of 1/γ². The smaller force and smaller acceleration as measured in the lab frame are a consequence of time dilation. Red Act (talk) 18:06, 16 August 2012 (UTC)

What you're missing is that, although mass is (usually) a reliable proxy for the conditions of stellar ignition, it's not the proximate cause of stellar ignition. That is, it isn't the mass itself which causes the stellar ignition, but rather the secondary effects (e.g. increased pressure and density) that are typically correlated with being a gravitationally bound system of gas in hydrostatic equilibrium exceeding a certain mass. When you go at relativistic speeds, you increase mass, but you don't necessarily affect those secondary things which are the actual cause of stellar ignition. -- 205.175.124.30 (talk) 21:05, 16 August 2012 (UTC)

How is the LHC able to sustain 5 trillion degree temperatures?

Forgive if the question is elementary, but I've searched both Wikipedia and the internet at large, and I haven't been able to find a suitable answer. The Large Hadron Collider has been in the news again, this time for creating what a Nature.com blog calls "the hottest manmade temperatures ever." In the article, it's estimated that this quark-gluon plasma, the source of the record-hot temperatures, reached 5.5 trillion degrees Celsius.

My question is: how could the LHC, or anything manmade for that matter, sustain temperatures that are apparently exponentially hotter than the center of the sun? The Wikipedia article on the LHC refers to "superconducting magnets," but I still don't understand how magnets alone can keep the components of the LHC from melting in the presence of trillions of degrees.

Thank you for your help! 65.6.139.251 (talk) 13:21, 15 August 2012 (UTC)

Because the amount of energy is put into only a few particles. Temperature generally refers to the average kinetic energy of particles. When you heat, say, a bowl of soup in a microwave, you're putting a relatively small amount of energy into an ENORMOUS number of particles, and the end result is you heat it up by a few degrees. At the LHC, they're putting a huge amount of energy into just a couple of particles, making it much easier to get those numbers skyrocketing. Goodbye Galaxy (talk) 13:41, 15 August 2012 (UTC)

For that reason it is really an abuse of language to call it temperature. --BozMo talk 15:39, 15 August 2012 (UTC)

Particle physicists are usually very careful to define temperature, and specify which particle or particles they are measuring when discussing temperature. Personally, I think it's more meaningful to discuss energy per particle, rather than temperature, because energy is a lot less ambiguous. You can simply multiply the Boltzmann constant by the temperature to get an energy quantity. Now, the question is, "to which particle or ensemble of particles does that energy value apply?" It isn't always obvious; and it's not exactly valid to say "each particle has that much energy." This conundrum makes clear that the description of temperature requires some contextual qualification. In an ordinary gas ensemble, we call that the "average kinetic energy of each gas molecule,"... but this description only applies in trivial textbook examples.

In this case, the value comes out to half an MeV - or, about the rest mass of the electron. So, a more scientifically rigorous publication might have said, "by colliding heavy ions, the new TeV facility at CERN has been able to impart kinetic energy to a relativistic electron equal in magnitude to its rest mass," a landmark accomplishment that few outside of the formally-trained physics community would appreciate. In fact, reviewing the speaker's publication, it looks like he's seeking parity violations in relativistic electrons. If you're interested in reading more, here is the website of Steven Vigdor, the Brookhaven scientist who led the LHC team in the latest experiment; and here is the website of website of Brookhaven Senior Scientist Dmitri Kharzeev, the scientist whose work was referenced in the Nature blog. It appears that the newest results were at ALICE in France/Switzerland, while prior high-temperature collision work was done at RHIC in New York. Nimur (talk) 17:28, 15 August 2012 (UTC)

From an unrelated white-paper, here's a better description than I could concoct - because it's written by a lab-director actively working in the field of high-energy heavy ion collisions: ..."the spectra of thermal photons radiated during the collisions, in combination with hydrodynamics calculations, indicate that the matter equilibrates at an initial temperature >~300 MeV (or 4 trillion Kelvin, about twice the QGP transition temperature predicted by lattice QCD), and in no more time than it takes light to traverse a proton." In other words, the temperature is very very high. Nimur (talk) 17:38, 15 August 2012 (UTC)

It doesn't sustain those temperatures. They exist for fractions of a second when the collisions happen, but that's all. --Tango (talk) 23:08, 15 August 2012 (UTC)

Why only one extant species of human

I was having a discussion with a friend on the concept of race, and I explained to him that race or subspecies does not exist in humans. In fact cro magnon which is probably more genetically distinct from any living human today is even considered to be the same subspecies as we are. So then he asked why this is. Why is it that among other animals, you can see a wide variety of different species and subspecies but we are the only surviving member of the genus homo when sapiens are known to co-exist with other humans such as neanderthalis and erectus in the past.

My attempt at an explanation is as follows. If a lifeform proliferates, its gene pool tends to become more homogeneous. If sapiens for example were to inflitrate territory occupied by erectus, they would inevitably come into conflict because they compete over the same exact resources. As history has shown, invaders also tend to rape the indigenous population and mix with the females, while killing off the males. So some X-linked traits should be absorbed into the invader, but for the most part, the invader's species is dominant (assuming they brought sapiens females with them, which they probably did). Also since they are so closely related, diseases that the invader possesses are likely to infect the defender's population and "help" kill them off. Using an analogy, if there was a "super wolf" that was capable of proliferating rapidly and spreading across the globe, it's likely that there would be only one race of wolves.

How is my explanation? Pretty close? Any problems? 148.168.40.4 (talk) 13:35, 15 August 2012 (UTC)

Plausible but I think you would need to find better stats on how many other animals have a variety of different species and subspecies and see if you could account for others before getting beyond plausible. None of the human behaviours you mention seems to be utterly unique to humans. --BozMo talk 15:36, 15 August 2012 (UTC)

The other lifeform that I found that comes close to being "super" and proliferated across the globe seems to be the Orca. According to the article, it seems that there could be several populations that are tentatively being categorized into subspecies or even species. I'm not entirely sure, but if I were to guess at an explanation for that divergence, it would be due to those populations being relatively isolated from each other for longer periods of time than human populations were. 148.168.40.4 (talk) 17:08, 15 August 2012 (UTC)

This - " If a lifeform proliferates, its gene pool tends to become more homogeneous." - is problematic, and not generally true. See speciation, and specifically sympatric speciation. Your description of competition and interbreeding among early Homo is otherwise basically consistent with the professional consensus on human evolution. SemanticMantis (talk) 16:17, 15 August 2012 (UTC)

• It's also not unconroversial how organisms are assigned to various Linnean classifications. There have been some who have argued for a single genus encompasing both humans and chimapnzee species (essentially combining the Pan and Homo genuses). The decisions on how to assign various groupings of animals to any one particular species/genus/family/whatever is somewhat arbitrary, and the "rules" so fuzzy around the edges as to be ultimately not very helpful. The only reason why there is only one "Homo" species extant is that taxonomists have only assigned one group of critters to the "Homo" genus. Any other explanation misses the point of taxonomy. --Jayron32 16:22, 15 August 2012 (UTC)

That's very true SemanticMantis. I guess I should rephrase how I put that. It seems the consensus among scientists is that sapiens left Africa about 60,000 years or so ago, and in just a relatively short period of time managed to proliferate all across the planet. Since our species doesn't reproduce quickly like fruit flies do, speciation amongst humans would require a lot more time and would require those populations to be isolated. So maybe I can rephrase it as such,

"If a slow reproducing lifeform proliferates quickly, its gene pool tends to become more homogeneous." 148.168.40.4 (talk) 17:04, 15 August 2012 (UTC)

However, you cannot base such a broadly worded proposal on a single species, being Humans. Human genetic diversity is highly constrained due to some historical population bottlenecks relatively recently: Toba catastrophe theory is one of them. Homogeneity among Humanity may be due to an event like that, and not to any particular principle of population genetics. --Jayron32 17:08, 15 August 2012 (UTC)

The part about disease works both ways. The Sapiens could have just as easily been killed off by diseases they caught from the Cro Magnon. No matter how "super" an organism supposedly is, humans still have adaptive immune systems that are much less effective against pathogens that we've never been in contact with before. 203.27.72.5 (talk) 20:47, 15 August 2012 (UTC)

Except that modern humans, if more widespread and in contact with each other, would have developed more immunity. Thus, when coming into contact with an isolated Cro-Magnon group, they would be far more likely to die from a disease the modern humans carried, just like with Native Americans when Europeans arrived. StuRat (talk) 21:15, 15 August 2012 (UTC)

I don't see any reason to suppose that early Homo Sapiens were in frequent contact with one another before the advent of civilization. 203.27.72.5 (talk) 21:51, 15 August 2012 (UTC)

There's evidence of trading going way back, such as one group possessing items not native to their area. StuRat (talk) 23:52, 15 August 2012 (UTC)

I agree with the lack of isolation of hominid populations as one cause, since modern humans either out-competed or outright killed other hominids as they came into contact with them. However, this also requires that we all be "generalists". Presumably, if each group if humans filled a unique niche, and didn't compete with each other, we wouldn't feel the need to kill off the competition, either. We would end up like Darwin's finches, which each had a different-shaped bill to get nectar from a different flower. StuRat (talk) 21:11, 15 August 2012 (UTC)

I am thinking it is human language that gave humans the advantage in coordinating hunts/raids/skirmishes (in addition to warning kin of danger) which would help in displacing existing hominid populations as they moved into new areas. Is there any evidence that any of these other hominids had language? We should also note that humans are known to have killed off many many other species as they moved into new hunting grounds, and these other hominids were likely seen as meat much like any other. SkyMachine ⁽⁺⁺⁾ 21:18, 15 August 2012 (UTC)

But if language was so important, how do you explain so many whales species, when they have such a well developed language ? StuRat (talk) 21:45, 15 August 2012 (UTC)

Cetaceans do NOT have a well-developed language. That assertion is probably one of the greatest popular misconceptions in lay science, and is promoted, all evidence to the contrary, by hippy green types. Whales have a language capability about the same as other herd mammals, like goats and elephants. Language means having dozens or hundreds of sounds which uniquely represent some noun or activity and are joined by a grammatical structure. Chant type songs are not good examples of language, as they are not giving much information to anyone else. It might be the case that a whale can make a sound which identifies himself (as in a name). When I see OTHER whales use this sound, as if to say “Willy is coming over tonight”, I will be impressed.In[the talk page for Cetacean intelligence] I proposed a good experiment to see if cetaceans can communicate like humans. You can read it there, but basically it involves two dolphins (or whales or whatever) having to confer as to where in a marine cave some food has been stored, so one of them can go there and spring the device which stores it. I believe that no scientist thinks that these animals would be able to do this. Myles325a (talk) 04:59, 16 August 2012 (UTC)

What a highly subjective nonsensical rationale. If all people thought like you, humans wouldn't bother learning other languages, because you'd consider any language which doesn't sound like your native language gibberish. Heck, even with sophisticated equipment, we still have trouble actually hearing what cetaceans are saying as much of it is too fast and waaay out of hearing range. Have you ever seen footages of dolphins hunting prey? Explain then how they coordinate extremely complex cultural (i.e. learned) behavior without some form of language?

Of course they can never be as complex as human languages. No other animal has that capability. The degree of complexity is relative to other forms of communication among other organisms, and they certainly ARE NOT on the same level as herd animals. Anthropocentrism at its finest.-- OBSIDIAN†SOUL 10:33, 18 August 2012 (UTC)

Your experiment sounds clever to you, so let's apply it to humans. Imagine I'm an alien that can fly, have no sense of sound, and communicate through color patterns in my skin. I can also see colors far beyond the ultraviolet and infrared range and eat through direct absorption of vapors through pores in my skin. I build structures on top of tall rocks where I keep xxzzfltbltbzz food dispenser and an instrument that prevents buildup of poisonous xxvavsss in my gut. Both of the latter are everyday essential things in my alien culture. All members of my species build those structures and possess those instruments, even the very young, only the mentally disabled don't.

Imagine if I picked two humans put them in a laboratory with tall rocks and the parts needed for building the structure as well as the instruments. Imagine to my surprise when the humans don't build a structure on top of the tall rock. Instead they do strange things like open those strange little holes at each other and waving their appendages and pushing the things about. Their skin don't even change color at all and they can't even make the instruments work (you shake it thrice and jiggle the thungmxzzzyzxt to the right and pull the huggvzasrrrt, and then turn your skin color greenish-purple). Would I conclude that humans aren't intelligent? By your reasoning, yes I would.-- OBSIDIAN†SOUL 10:52, 18 August 2012 (UTC)

Whales for the most part generally hunt things smaller than themselves. Humans go for a range of prey, many being larger than themselves which require coordinated group hunting to take down, so language has a much bigger impact in this scenario. SkyMachine ⁽⁺⁺⁾ 21:52, 15 August 2012 (UTC)

Some whales use highly coordinated hunting methods. Humpback whales designate one whale to go low and blow a bubble ring, that causes the fish above to form a bait ball, which all the whales then devour. Orcas will coordinate an attack on larger whales, say to drive a baby whale away from the protection of the pod, so they can kill and eat it. StuRat (talk) 23:49, 15 August 2012 (UTC)

Good point, yes it is amazing what millions of years of evolution by natural seletion can achieve. Whales are not killing whales though, are they? However, with humans it was all very rapid (<1million years) so a technological/societal emergence is valid to speculate on as the reason why they blitzkrieged the close competition. SkyMachine ⁽⁺⁺⁾ 04:06, 16 August 2012 (UTC)

In the case of orcas (killer whales), they certainly do kill other whales. StuRat (talk) 04:19, 16 August 2012 (UTC)

Saying that early modern humans (Cro-magnons) are considered the same species as people today doesn't really mean much. Spacially isolated organisms of the same species can become separate species over time, and that can be tested by looking at the viability of hybrid offspring. Temporally isolated organisms such as us and Cro-magnons may have experienced enough genetic drift and selection pressure in the interim that we would fail such a test, but it cannot be carried out anyway. You may also be interested in Species problem. 203.27.72.5 (talk) 21:45, 15 August 2012 (UTC)

• Lack of isolation, as mentioned above, is the main issue. Behaviorally modern humans have bee around since just before the Toba supervolcano bottleneck at 75,000 bp. Genetic, archaeological and linguistic evidence all converges at that date for the origin of extra-African modern humanity. The Neanderthals and ebu gogo did not long survive intense contact with H sapiens sapiens. μηδείς (talk) 22:30, 15 August 2012 (UTC)

Not meaning to nitpick, but a couple of caveats here. "Behaviorally modern humans" is by a nature a pretty subjective term, since many aspects of behaviour which do not leave paleontological record are very vaguely understood as to exactly when and how they arose. Language, for one. It's one of those situations where most serious researchers will just tell you straight up it's a bit of a guessing game and though theories abound, none has concrete empirical evidence. There are plenty of examples where for other aspects of human psychology and culture, once we get into prehistory, the trail runs cold. Anatomically Modern Human is the much more common and (somewhat) less debated term. Theories for this have ranged considerably over the years from about 75,000 to 200,000 years, but my (admittedly impressionistic and in no way compiled or sourced) perception over recent years has been that somewhere around 140,000-160,000 years ago seems appears to be winning out as a likely rough arrival point of the distinct species. Also, the Toba Extinction hypothesis is not really settled fact by any measure. A lot of researchers agree some sort of bottleneck likely occurred, but timing and cause are debated. Snow (talk) 02:58, 16 August 2012 (UTC)

The Chimpanzee-human last common ancestor is estimated to be around 6 million years ago. What are some of the most "isolated" living species measured by the estimated age of the last common ancestor to another living species? PrimeHunter (talk) 00:51, 16 August 2012 (UTC)

Apparently the Nile crocodile separated from the rest of crocodylus during the pliocene (5.3 million to 2.6 million years ago). But again, there's no guarrentee that a modern Nile crocodile could produce viable offspring with one from the distant past. And besides, my DeLorean is in the shop. 203.27.72.5 (talk) 02:06, 16 August 2012 (UTC)

That's not a very helpful question in the case of humans. Some "living fossils" (they'd be called language isolates in linguistics) only have very, very, very distant closest relatives, like the aardvark, Amborella trichopoda, Latimeria, and Ginko biloba. μηδείς (talk) 02:24, 16 August 2012 (UTC)

That's a hard question to answer. If you classify placozoa as a single species, as some biologists do, they probably separated from every other living species well over 600 million years ago. You can't get much farther back without going to single-celled organisms, where the very concept of a species becomes problematic. Looie496 (talk) 02:24, 16 August 2012 (UTC)

To the OP, your take is basically consistent with one of the leading theories on the matter. Note that a number of human subspecies did evolve in isolated global regions and coexist for significantly long periods of time. However, when Homo Sapiens sapiens came on the scene, they occupied a significant overlap in ecological niche with these species but they spread faster and had significant advantages over their predecessors. Though in the last couple of years it has come to be considered established fact that at least two of these other species of primate seem to have interbred with Homo Sapiens. Note that the degree to which disease played a role is debatable; the reason that huge epidemics arose after contact between historically recorded groups of humans was that some of these people had been involved in extensive animal domestication and had inherited some of their diseases but also immunities against them -- they shared the diseases with those they came into contact with those who had not been in close contact with other animal species and thus had not been a vector for mutated stains of animal-originating diseases to give back (hence why Europeans did not pick up significant new diseases from the America after contact, but their diseases ravaged the Americas (for a fuller discussion of this process, Jared Diamond's Guns, Germs, and Steel is a can't-miss read; his The Third Chimpanzee also treats the origin and spread of anatomically modern humans and how they arose from animal origins and, to a limited extent, how they competed with their immediate predecessors). For more general info on the subject matter of what separates individual but closely related species and how they can co-evolve and compete, The Structure of Evolutionary Theory is a great, if sometimes clinical, reference. Snow (talk) 02:58, 16 August 2012 (UTC)

Myles325a back live. To OP: It is eye-opening to see the number of hypotheses presented above as matters of record. I’ll do the QI thing and put up the “Nobody Knows” flag. Some scientists BELIEVE that we (Sapiens) wiped out or out-competed Neanderthals. But nobody knows; it is a wide open question. And there were dozens of hominoid beings in the past. Did we wipe them all out, including the really isolated ones like the so-called “Hobbits”? I don’t think so, but then - nobody knows. Recently, I started a list of wide-open questions in science which can be found here [myles’ list of wide open science questions]. It is no. 3 there, along with some comments and additions. Myles325a (talk) 05:21, 16 August 2012 (UTC)

One minor correction to the OP: I don't think it's the case that Cro-Magnons would be more genetically distinct than living populations. Cro-Magnon fossils are less than 50,000 years old, so after the emergence of modern humans from Africa and the colonization of most of the Old World, including Australia. I don't know if there has been any genetic analysis of Cro-Magnons, but I would expect them to be less distinct than some modern populations. John M Baker (talk) 20:08, 16 August 2012 (UTC)

West Nile vaccine for humans

This is a general question related to the article West Nile virus and not a request for medical advice. In the US, West Nile disease seems to be in a resurgence this year, with Texas recently declaring an emergency due to the rising number of infections and deaths. The CDC says there is a vaccine for animals, but no vaccine for humans.[5] "Chemirivax-West Nile" vaccine was in the news from 2002 through 2008. It was a vaccine made from Yellow Fever vaccine by adding something from the West Nile virus, and was found safe in human trials and to protect from the virus in animal trials. Authorities sometimes spray poison from trucks and airplanes to kill the mosquitoes, over the objection of residents of the areas, and advise people in affected areas to stay indoors, or to douse themselves with possibly toxic repellants when spending time outside, so a safe and effective vaccine would be of considerable interest. Over 100 people get a mild asymptomatic infection for every severe infection, and studies of the African population imply that a history of such exposure might produce antibodies which confer some protection against future infection. a)Is there a test available clinically to determine whether an individual has such antibodies from a past mild infection? b) What is the status of candidate vaccines which are being developed for human use?Are any in Phase 3 trials? Edison (talk) 19:11, 15 August 2012 (UTC)

A report of a Phase 2 clinical trail for the Chemirivax vaccine was published last year, see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086439. Several other vaccines are in earlier stages of testing. I can't find any mention of a Phase 3 trial. Looie496 (talk) 19:33, 15 August 2012 (UTC)

Checking into whether this involved media exaggeration, I found that Texas has half of the total U.S. reported cases so far this year [6] and the number of cases is more than twice the number reported at this point last year. Rmhermen (talk) 20:31, 15 August 2012 (UTC)

The NY Times in 2003 said that every infected person becomes immune to the disease for life. Is that reliable sourcing for adding the info to the West Nile virus article? Edison (talk) 22:14, 15 August 2012 (UTC)

The Times would likely have quoted some authority. You'd be best off saying something like: "The CDC, according to the NY Times, has said that...." μηδείς (talk) 02:15, 16 August 2012 (UTC)

Mars Reconnaissance Orbiter photo of Curiosity

This photo of the Curiosity rover parachuting down to the surface of Mars, taken by the Mars Reconnaissance Orbiter, has been circulating quite widely.

Does anyone know of a version of it without the white box around the rover? (Yes, I could edit it out with Photoshop, and I may have to for my intended purpose, but if I could find the original, all to the better.)

Thanks. --Mr.98 (talk) 20:14, 15 August 2012 (UTC)

Ah, after more poking around, I found it! It's the big half-gig file on the bottom — you have to play a little game of Where's Waldo, but the rover is there, unmolested by annotation. --Mr.98 (talk) 20:32, 15 August 2012 (UTC)

Can I ask why you objected to the white box ? StuRat (talk) 23:44, 15 August 2012 (UTC)

Resolved

Increasing human intellect?

I was told today by an unbearably cocky teenager (awaiting his A-Level results) that it was scientific fact that people are more intelligent now than they were 100 years ago. As I'm just over half that age, I took it as a bit of an insult. Is there any evidence available, that humans are NOT more intelligent now, they just know different stuff? I know disproving an assertion is harder than proving one but I live in hope. I want something to wave under his nose in a triumphant fashion please (Vanity, vanity, all is vanity!). Alansplodge (talk) 22:23, 15 August 2012 (UTC)

See the Flynn effect. 203.27.72.5 (talk) 22:31, 15 August 2012 (UTC)

D'oh! Alansplodge (talk) 23:19, 15 August 2012 (UTC)

Sure they are. That's why nobody goes to war anymore. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:00, 15 August 2012 (UTC)

Assume that the youngster is correct, and tell him that in correspondence to his increased intellectual capability, you will consequently expect improved overall performance, productivity, and innovation from him and other representatives of his generation. Using quantitative psychometrics such as the standardized testing model, one can expect to rapidly accelerate the progress of our species. Be sure that he understands that you hold him personally responsible for accomplishing that task. Nimur (talk) 23:01, 15 August 2012 (UTC)

Well, back in the Middle Ages, average intelligence might very well have been less. That is, while people were presumably conceived with the same mental capacity as they have now, a combination of malnutrition, drinking alcohol, and lack of mental stimulation likely resulted in diminished capacity by adulthood. Of course, none of this applies to the small group of wealthy people (except perhaps the alcohol), who could be as brilliant then as now.

TV might have represented a low in mental stimulation for modern people (with a few exceptions, like PBS shows), but more interactive forms of communication might again have started to improve things. StuRat (talk) 23:40, 15 August 2012 (UTC)

Maybe yes, but not necessarily in the way he means. There's quite a bit of evidence that suggests that severe perinatal and childhood malnutrition contributes to lower adult IQ[7][8][9]. If we can then show, in a population, that malnutrition has decreased over the time in question, I don't think it's a huge jump to say that the number of people in that population with IQs lower than they would normally be would be reduced - that would raise the average IQ of that population, and so one could say "of this population, the mean IQ has increased over this period". This paper says that is the case for Vietnam (over the 1990 to 2004 period). So, waving one's statistical hands a bit, I think one can say e.g. "the average IQ of people born in Vietnam in 2004 is greater than those born in 1990". But I assume you and he were raised in the UK, not a developing country like Vietnam. Those papers I cited at the start all talked about medically significant malnutrition, and I don't think your 1960s meat-and-two-veg upbringing was really materially less nutritious than his 1990s turkey twizzlers diet. I can't find a source that says whether the overall proportion of people in the world who are malnourished is less than it used to be, but my strong inclination is that it is. If that is true, I think you can say "humans are more intelligent now", but not that "Britons are more intelligent now". So you had a slight statistical advantage over the "average human" when you were his age that has been eroded some for him. Whether he should be happy or sad about that is another matter. -- Finlay McWalterჷTalk 23:49, 15 August 2012 (UTC)

As I understand it, there's quite an epidemic of binge drinking in the UK now, which may lower IQ a bit. StuRat (talk) 23:57, 15 August 2012 (UTC)

If your mother drank heavily while pregnant with you, or if you drink a lot during childhood, that might impact IQ. I doubt it has much effect in adulthood, though. The "alcohol kills brain cells" thing isn't really true. --Tango (talk) 00:21, 16 August 2012 (UTC)

But it's probably Alansplodge's generation doing the binging. This paper (p9) from the Joseph Rowntree Foundation shows steady-ish rates from the late 1970s, but for a marked increase in wine consumption. That graph stops in ~2005: UK drinkers now drink 13% less than 2004. The Rowntree paper (p6) says excessive consumption among young adults has fallen since 2000 (back to 1988 levels - so before that steep spike), but increased in older age groups (that's who's drinking all that extra wine). So I think there's little evidence that UCT's generation in incurring much more alcoholic brain damage than Alansplodge's. Maybe from Teletubbies, but not drink. -- Finlay McWalterჷTalk 00:24, 16 August 2012 (UTC)

Ya, those Teletubbies could turn anyone into a vegetable. But I do think binge drinking does more damage than steady drinking. Has the rate of binge drinking increased ? StuRat (talk) 00:31, 16 August 2012 (UTC)

Epidemiology of binge drinking#United Kingdom says "Among young people (under 25), binge drinking (and drinking in general) in England appears to have declined since the late 1990s according to the National Health Service." Binge drinking#Central nervous system suggests the evidence on the effects of binge drinking on mental processes isn't very decisive. -- Finlay McWalterჷTalk 00:49, 16 August 2012 (UTC)

Technology builds on previous technology, so there may be an illusion that people are getting more intelligent, but that doesn't mean they're getting any "smarter". To quote Will Cuppy, "The Dark Ages were called the Dark Ages because people then weren't very bright. They've been getting brighter and brighter ever since, until they're like they are now." ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:58, 16 August 2012 (UTC)

Thank you one and all for your replies. I'm rather cheered by the detail of the "Flynn effect" article which says that only the dimmest folk have got brighter over the last century, those of average intelligence have not improved and the most intelligent may actually be getting less so. Alansplodge (talk) 18:30, 16 August 2012 (UTC)

Resolved

I think it's time for a little gratuitous Lysenkoism, courtesy of epigenetics. [10] Wnt (talk) 10:18, 17 August 2012 (UTC)

It also depends on how one defines "intelligence". Take one of these supposedly super-smart characters from today and plunk them into, say, England in the year 1066, and see how their high-tech intelligence would serve them, i.e. how long they would survive. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:23, 17 August 2012 (UTC)

Indeed. I remember from childhood an elderly friend of my parents who could mentally add three long columns of figures simultaneously; those columns being pounds, shillings and pence which involves adding-up pence in base 12 and shillings in base 20. An impressive feat and very useful in an office at one time, but quite pointless today. Alansplodge (talk) 16:28, 17 August 2012 (UTC)

That reminds me of the self-service restaurant in Blacklers (Liverpool) many years ago (before modern tills) when a woman with Savant syndrome was employed to add up the total cost just before the till. Dbfirs 07:46, 18 August 2012 (UTC)

August 16

How are the life cycles of Mollusks and Insects alike?

How are the life cycles of Mollusks and Insects alike? — Preceding unsigned comment added by 175.140.183.44 (talk) 00:51, 16 August 2012 (UTC)

See Insect#Reproduction_and_development and Mollusca#Reproduction. 203.27.72.5 (talk) 01:14, 16 August 2012 (UTC)

Why, do you have crabs ? ...or perhaps an unfinished homework assignment ? StuRat (talk) 01:35, 16 August 2012 (UTC)

Very little at all that they do not share with all animalia, except for the fact that they lay eggs and have protostome development. μηδείς (talk) 02:13, 16 August 2012 (UTC)

For starters, they're born (or hatched or whatever) and eventually die. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:55, 16 August 2012 (UTC)

As usual Bugs, you've hit the nail right on the head. I'm sure that the OP will be impressed by your insightful and erudite answer. Alansplodge (talk) 18:15, 16 August 2012 (UTC)

I do what I can. Next I expect the OP to ask why a raven is like a writing desk. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:53, 16 August 2012 (UTC)

Both insects and mollusks belong to Protostomia and Bilateria. However insects are in the Ecdysozoa superphyllum with mollusks in Lophotrochozoa. In terms of lifecycle they lay eggs, grow some kind of embryo, hatch, and mate. Graeme Bartlett (talk) 09:53, 17 August 2012 (UTC)

Loch Ness monster

What do scientists have to say about the Loch Ness Monster now, after this new photo? Bubba73 ^{You talkin' to me?} 03:13, 16 August 2012 (UTC)

"Wow, yet another meaningless, fuzzy photo". StuRat (talk) 03:59, 16 August 2012 (UTC)

And he saw it for 5-10 minutes - it would be nice to have a sequence of photos. Bubba73 ^{You talkin' to me?} 04:35, 16 August 2012 (UTC)

Bearing in mind that "extraordinary claims require extraordinary evidence", I'd say we need a chunk of Nessie herself, for DNA testing, at the very least. I look forward to that day, if only because it will cause them to play one of my favorite songs by The Police again. StuRat (talk) 04:46, 16 August 2012 (UTC)

My award for the most incorrect maxim is the "Extraordinary claims..." one, closely followed by "What you can't see, can't hurt you. Those who are totally partisan about some notion will "require" massive evidence to the contrary to overturn their prejudices. Logically speaking, the amount and quality of evidence to refute (or corroborate) any theory should be the same, regardless of how loyal we are to the one held at the time. To say that one needs "extraordiany" evidence for much-favoured theories of long-standing is just another way of putting a tariff on their rivals. Myles325a (talk) 05:44, 16 August 2012 (UTC)

Not following you at all. That a population of dinosaurs could exist in Loch Ness is an extraordinary claim. Fuzzy photos are not extraordinary evidence. A claim which is not extraordinary, like that there is a newly discovered species of purple fruit fly deep in the Amazon, wouldn't need such extraordinary evidence. A simple photo might be enough (although it would need to be clearer than those Nessie photos). StuRat (talk) 06:13, 16 August 2012 (UTC)

You have just restated your initial case, with no response to mine. My take is that in a formal way, labelling claims as "extraordinary" or "plausible" or "obvious" is to beg the question and alrady accord them a status that should be argued for, not applied at the outset. We should be just as satisfied / dissatisfied with evidence for a new species of fruitfly / dinosaurs in Lock Ness, and not expect the former to be "extraordinary" while the latter can just be "routine". That is the way entrenched theories retain their status, they are grandfathered in. This is an important point in the Philosophy of Empiricism, and is well-expounded by Karl Popper. the foremost philosopher of the Logic of Scientific Discovery. Myles325a (talk) 07:00, 16 August 2012 (UTC)

A better way to phrase the maxim would be to ask, what about the world as we know it would have to be different to make this endpoint seem more likely than any other? To have a dinosaur-like creature in a lake of that size would require quite a lot of jumps, mainly: 1. that this creature has survived for a long time without leaving significant evidence, despite all of the troublesome ecological things that would imply; 2. that somehow a breeding population of these creatures has survived long enough to significantly overlap with human occupation of the area, without leaving significant evidence. We contrast that with the steps that require these things to not exist: 1. human beings are superstitious, easily fooled, and/or have a variety of reasons for misleading one another. The latter narrative is easy to imagine — it requires no leaps whatsoever, since we have ample evidence of this sort of thing. The former narrative is hard to imagine: it would require quite a lot of unexpected junctures (unexpected in the sense that we don't have similar evidence). This isn't open and shut logic, but it does seem to suggest that if one is going to believe in the other narrative, and think it likely, then one would require fairly solid evidence in favor of it. "Extraordinary evidence" is just a reworking of Occam's Razor, and is as such just heuristic, but it is a useful heuristic. There are lots of things which, taken in isolation of the narratives that lead to them, sound fantastical. The notion that someone put an SUV-sized robot on Mars would be a completely fanciful, ridiculous idea, were there not a very well-documented chain of events leading up to it. (In any case, without wanting to appeal to authority, no philosophers of science think Popper's discussion of any of this is very adequate. It is popular mainly amongst people who do not understand it very well — which is to say, science popularizers or partisans — not philosophers, historians, or philosophically-minded scientists.) --Mr.98 (talk) 17:35, 16 August 2012 (UTC)

I agree with most of your comment but I wouldn't dismiss Popper so easily. I took an undergraduate unit in philosphy of science when I was doing my BSc and a large chunk of the curriculum was based on his work. 203.27.72.5 (talk) 23:17, 16 August 2012 (UTC)

He's an important figure to know, and was very influential, but once you get beyond the introduction to the philosophy of science, most of what remains is about how completely incorrect he was in articulating how science works in practice (no scientist acts like a Popperian actor, and most of them do exactly the opposite of what he says they should be doing) or even could work (even something as seemingly obvious as falsifiability becomes maddeningly difficult to reconcile with how actual practice would go down). There are probably a few rogue Popperians around but they are far more rare than the people who recognize that his stuff has big problems and doesn't really do what he thought it did. But this is a separate issue. --Mr.98 (talk) 00:46, 17 August 2012 (UTC)

In an ideal world, perhaps. In the real world, there are many people who would fake Nessie, just for a bit of publicity and/or business, but few who would fake the purple fruit fly in the Amazon, as it's existence is hardly going to boost the tourism industry there. If you require the same standard for both, then you will either end up accepting many hoaxes involving Nessie, Sasquatch, etc., as proof of their existence, and/or rejecting perfectly plausible evidence of lesser species.

This reminds me of the similar problem in math (we have an article on it, but I forget the name). "If somebody hands you what he claims to be a fair coin, and you then toss heads 200 times in a row, what are the chances of it happening again, if you toss it another 200 times ?" Well, mathematically, the chances of the first 200 times being heads were 2²⁰⁰, or some 1.6×10⁶⁰, and the odds of the second 200 tosses being heads would be the same. However, it's perfectly absurd, in the real world, to believe that it's a fair coin, after getting 200 heads in 200 tosses. Thus, once we reject this assertion, the probability of tossing another 200 heads in a row is far higher than the theoretical math would indicate. StuRat (talk) 07:55, 16 August 2012 (UTC)

Popper's views about how science works are kind of outdated. You might be interested in the work of Thomas Kuhn. Consensus plays an important role in the functioning of science. If all hypotheses were given equal weight until disproved, nothing would ever get done. There are too many possible hypotheses, and not enough time to refute them all. Requiring stronger evidence to support large changes in current understanding is one of several tools for getting around this problem.--Srleffler (talk) 06:15, 18 August 2012 (UTC)

The conflict between Popper's principles and the practical principles that permit Wikipedia to function (see WP:EXCEPTIONAL) is kind of fascinating. (One major difference is that Wikipedia isn't interested in verisimilitude, only notability and reliable published sources, and will often present multiple conflicting conjectures if they are all notable and published.) I expect there's some re-phasing of the maxim that could allow compatibility with Popper. How about this: a claim which, if true, would cause a radical and wide-ranging shift in our ideas, will prompt a great deal of criticism. Though, of course, cutting to the chase and beginning the actual criticism seems better than saying the rather vacuous maxim. The maxim may have some use in the form "don't brush aside obvious criticisms".  Card Zero  (talk) 10:29, 16 August 2012 (UTC)

Occam's acusector: Why say versiml... verlers... verismirl... vrslrmrtd when you can just say truthiness! -- OBSIDIAN†SOUL 07:36, 18 August 2012 (UTC)

"Spirits in a Material World"? Dismas|^(talk) 05:02, 16 August 2012 (UTC)

Not quite: [11]. StuRat (talk) 05:14, 16 August 2012 (UTC)

Not enough surface ripples for a beast of that suppossed displacement. SkyMachine ⁽⁺⁺⁾ 04:49, 16 August 2012 (UTC)

Maybe it was shagged out after having a long yodel (These beasties yodel, did you know that?)

"George Edwards takes his boat, “Nessie Hunter,” out onto Loch Ness nearly every day, often with tourists" conflict of interest, anybody? 203.27.72.5 (talk) 05:22, 16 August 2012 (UTC)

I've had a close look at that photo, and in all humility, I am something of an expert in this field. My opinion is that that object would have caused the person who produced it considerable pain in the anal region. Myles325a (talk) 05:34, 16 August 2012 (UTC)

You're an expert in the field of butthurt? Someguy1221 (talk) 06:16, 16 August 2012 (UTC)

The size and movement (or lack thereof) in the ripples in the water suggest to me that this is a rather small object that's basically floating - as with the famous 1930s photo of Nessie that proved to be a toy submarine with a fake neck and head attached. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:53, 16 August 2012 (UTC)

As another self-considered quasi-expert (well, a member of the CFZ, anyway), I disagree that the photo has "proved" to be a toy submarine. It may be true, but is based on an alleged deathbed confession of a supposed conspirator reported many years after said death: either the deathbed confession itself or the very belated report of it may themselves have been jokes/hoaxes, as there is (to my knowledge) no corroborative evidence for either. Personally, I've always thought that the photo in question looks suspiciously like a slightly motion-blurred Diver (aka loon). {The poster formerly known as 87.81.230.195} — Preceding unsigned comment added by 84.21.143.150 (talk) 13:11, 16 August 2012 (UTC)

In the full photo, not the cropped version, it's clear that the "monster" is very small. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:51, 16 August 2012 (UTC)

A dead fish. AndyTheGrump (talk) 14:02, 16 August 2012 (UTC)

That was what it looked like to me at first too. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:51, 16 August 2012 (UTC)

And, in any case, Weekly World News used to publish much better photos of the Loch Ness monster.--pma 18:36, 16 August 2012 (UTC)

It's a Skarasen whoviensis. μηδείς (talk) 21:26, 17 August 2012 (UTC)

Does Neanderthal DNA show nature of sexual unions?

Like many others I was fascinated to learn that research had shown that Sapiens and Neanderthals had reproduced, and so there is some Neanderthal DNA in our chromosomes. It is the usual case that a dominant culture takes the females of the weaker culture for breeding purposes. I wonder if there are signs on our X chromosome and in the mitochondria that might show the non-symmetric nature of such sexual unions. (Dominant cultures might also take male slaves from those they defeated or colonised, but I am assuming that such practices came much later). Myles325a (talk) 05:30, 16 August 2012 (UTC)

Research related to the Neanderthal genome project has not revealed any evidence of Neanderthal mitochondrial DNA in humans. Comparison of human and Neanderthal genomes shows the mixture of genes is similar across all chromosomes. This doesn't rule out that there was a particular mating pair (male human versus female human) that dominated the sexual interaction between the two species, but it does suggest that such interactions were rare relative to human-human matings. Unfortunately, the three Neanderthals used in this project were all female, so the researchers did not have any Neanderthal Y chromosomes to use as a reference. If we had such chromosomes, answering your question might be possible. The presence of Neanderthal Y in modern humans would show that Neanderthal-male to human-female matings occured, and its suspicious absence would suggest that the interspecies matings were the reverse. Someguy1221 (talk) 06:12, 16 August 2012 (UTC)

The latest research seems to suggest that such matings may not have taken place, and that the presence of DNA similarities may rather have arisen from shared ancestry. Ghmyrtle (talk) 08:04, 16 August 2012 (UTC)

I think it is fair to say that this is an unresolved question with some strongly held opinions and a lack of sufficient data. Rmhermen (talk) 14:46, 16 August 2012 (UTC)

what was there before the BIGBANG ?

KINDLY GET ME THE ANSWER FOR,WHAT WAS THERE BEFORE THE BIGBANG. — Preceding unsigned comment added by 117.213.57.60 (talk) 05:37, 16 August 2012 (UTC)

That was the "Age of the Stuck Caps Lock". The BIGBANG, as you put it, began when supersymmetry broke the fusion between Caps and Lower Case, and set both of those free to interact with each other, creating title case, and so on. Read all about it here: Big bang— Preceding unsigned comment added by Myles325a (talk • contribs)

As far as I know, time began with the Big Bang, so it makes no sense to ask what happened "before" the Big Bang. It would be like incorrectly assuming the world is flat and asking what is over the edge of the world. Plasmic Physics (talk) 05:55, 16 August 2012 (UTC)

Snarkiness aside, no one knows. As you will read in the linked article, theories range from "another universe" to "nothing" and "something else". There is no solid evidence for any pre-big-bang theory. Someguy1221 (talk) 05:56, 16 August 2012 (UTC)

Possibly that is where the God of the gaps resides. SkyMachine ⁽⁺⁺⁾ 06:33, 16 August 2012 (UTC)

The BIGFOREPLAY? Clarityfiend (talk) 10:17, 16 August 2012 (UTC)

No one knows, and you should be skeptical of anyone who claims to know. In religious terms, this question is equivalent to 'what made god.' However, your question would be much more useful if you instead ask "What could have existed before the big bang?" Some possibilities include Absolutely Nothing (See the lecture on youtube, "A Universe from Nothing" by Lawrence Krauss here), and a previous universe that collapsed (went though a Big Crunch). Or, of course, "Anything else." The problem with any sort of scientific evaluation of this question is that almost by definition, there would be no physical evidence or remaining clues or pieces of whatever there was, so there is no evidence to make a judgement in any direction. For all we could tell, "A pink fluffy easter bunny" could be what there was before the big bang, and there's not a shred of evidence in this universe that could disprove it. Ehryk (talk) 10:37, 17 August 2012 (UTC)

The Big Bang itself is a scientific theory based on observed evidence, i.e. it's not a "fact" as such, but rather it's our best educated-guess for how the universe began. As you indicate, there is no known evidence for what might have occurred, if anything, before the Big Bang. So we can only hypothesize, at best. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:19, 17 August 2012 (UTC)

blueshift and redshift.

If something is blueshifted does it appear visually blue or is it just that the spectral lines sre shifted to the blue end of the spectrum?

If it doesn't appear visually blue is there a point where if blueshifted enough that it would appear visually blue? — Preceding unsigned comment added by 92.23.113.145 (talk) 11:02, 16 August 2012 (UTC)

It depends on the amount of the blueshift, and on the original colour, but yes, receding approaching objects appear (marginally) bluer than they really are. This is noticeable in distant stars that often appear blue. For a moderate blueshift, red might appear yellow, yellow might appear green etc. (See next comment -- my brain must have slipped out of gear! ) This is most unlikely to ever be observed. Dbfirs 11:28, 16 August 2012 (UTC)

Stars within our Galaxy recede by no more than, say, 300 km/s. This induces a redshift $\Delta \lambda /\lambda \approx v/c$ of about 0.1 per cent. That is by far not enough to be noticeable visually; you need a spectrograph to measure the shift of absorption or (rarely in stars) emission lines. You may be thinking of galaxies, and yes, there are highly red(!)shifted galaxies that appear blue. That colour has nothing to do with the redshift, it is due to the fact that these galaxies contain lots of young stars which have a spectral energy distribution that increases towards the ultraviolet. The visual appearance depends on the spectral energy distribution of an object's light, the red- or blueshift is a secondary effect to the visual appearance, which is not uniquely "red" or "blue" (it is defined as a shift of the spectrum towards longer ("redder") or shorter ("bluer") wavelengths). --Wrongfilter (talk) 11:59, 16 August 2012 (UTC)

Thanks for the gentle correction to the rubbish I wrote. I've partially corrected it. Dbfirs 22:00, 16 August 2012 (UTC)

See blueshift, red shift and Doppler effect. What the answerers above have danced around but not explicity mentioned is that it is not restricted to visible light. The words blueshift and redshift derive from the appearance of the effect when it is in the visible spectrum, but they generally refer to any apparent shortening or lengthening of electromagnetic waves due to relative motion between the source and observer. This may be X-ray to gamma, or microwave to radio, or red light to blue light, or an infinite number of other possibilities. 203.27.72.5 (talk) 23:35, 16 August 2012 (UTC)

The affect on the visible colour is going to depend on the initial colour, including what is happening outside the visible spectrum. Depending on how large the blueshift is, the visible light you see may have started out as infrared or even microwaves (although that would be a lot of blueshift - you would probably need a black hole to be involved or something to get that). The object will only actually appear bluer if the amount of the blueshift is such that its previous peak moves into the blue part of the spectrum. --Tango (talk) 12:04, 17 August 2012 (UTC)

war planes

how come libya was so inaccurate dropping bombs during the Libyan civil war. I remember several instances of video footage of a Libyan bomber plane coming in dropping bombs on rebels and they wouldn't even make it within 100 yards of the target. However, during the current Syrian conflict The government who is using many of the same fighter planes has been deadly accurate with their bombs.--Wrk678 (talk) 13:33, 16 August 2012 (UTC)

Training? Better munitions? Good military intelligence? More willingness by the pilots to bomb their countrymen? Less crosswind? There are any number of reasons why outcomes are not identical when you vary the starting conditions. — Lomn 13:42, 16 August 2012 (UTC)

my first though would be training but there are actually some "training films" of old MIG jets and they seem fairly easy to bomb with and quite accurate. The strange thing is the Libyan army was known for being very accurate with their mortars and artillery which they demonstrated well during the uprising. --Wrk678 (talk) 14:32, 16 August 2012 (UTC)

Training films (presumably assembled by the very best pilots under ideal non-combat conditions) and artillery (which has nothing whatsoever to do with flying planes or training pilots to fly planes) are not compelling counterexamples. — Lomn 15:39, 16 August 2012 (UTC)

Precision munitions leave little work up to pilot skill. In the jet era, the aerial advantage has shifted from the country with the best pilots to the countryparticipant-combatant with the best economy, research-and-development infrastructure, and (in the case of "other-than-superpower" air forces), the ability to acquire quality imported equipment and munitions. So, this become an issue of international politics and arms trade; logistics and supply-chain management. For in-depth, public-disclosed discussion of the Syrian air force and its capabilities in 2012, you may find this August 1 testimony to Congress by RAND expert James Dobbins enlightening.

And, while perusing the RAND website, you may also find their 2012 Air Force Materiel Command Reorganization Report informative, if you want to establish a background level of knowledge about modern air force supply-chain management. Nimur (talk) 17:58, 16 August 2012 (UTC)

Maybe the pilots were tuned into the revolution and it was a foregone conclusion that it was time for a change, so they missed on purpose.165.212.189.187 (talk) 18:04, 16 August 2012 (UTC)
I don't think they were as bad as you might think overall. According to this article, they managed to push back a rebel advance along the north coast with airstrikes. Apparently, these attacks were more accurate then previously seen. According to the wikipedia article on the Libyan Air Force, they even managed a successful bombing mission under the no fly zone, though it cited a blog as its source. 203.27.72.5 (talk) 02:22, 17 August 2012 (UTC)

asenapine

hai, pl anybody give me information regarding teratogenic effect of asenapine. — Preceding unsigned comment added by 203.6.211.98 (talk) 13:51, 16 August 2012 (UTC)

Product information about Sycrest, which is one branded form of asenapine, is here. It says "There are no adequate data from the use of Sycrest in pregnant women. Asenapine was not teratogenic in animal studies. Maternal and embryo toxic effects were found in animal studies" and gives further details of the animal effects. This site says that in the US, the Food and Drug Administration classifies asenapine as a "C" in terms of its teratogenic effect, which means "Animal studies indicate a risk but there is no safety data in humans". Aside from publicly available documents such as these, we can only refer you to a qualified medical advisor for further information, and this is also the advice on the various websites that discuss asenapine use during pregnancy. - Karenjc 15:58, 16 August 2012 (UTC)

How long does it take to go from patent to commercialization?

I am working on a research project and I need some data on how long it takes from the time a patent is filed to the time of first sale or the time of commercialization. I have been looking for a while and haven't really been able to find much except for this paper: http://onlinelibrary.wiley.com/doi/10.1002/smj.643/abstract.

Does anyone know of any other studies or datasets? Thanks. Eiad77 (talk) 14:08, 16 August 2012 (UTC)

Are you asking for an overall average? I suspect it will somewhat depend on what the patent covers. While many patents cover things which have some time to market, the likely steps needed on average will tend to vary. Drugs for example have a number of specific regulatory steps that they need to go through so any patent covering them may have a resonable time between patent and first sale whereas many other patents (software patents for example) may not generally cover things requiring such steps. Nil Einne (talk) 16:34, 16 August 2012 (UTC)

Any data would be better than nothing, but I'd be most interested in engineering patents. Eiad77 (talk) 16:38, 16 August 2012 (UTC)

If the inventor or his company isn't worried about someone else inventing the same thing before the application being filed, sometimes the application isn't sent in until just before commercialization, so the commercialization comes before the patent. Jc3s5h (talk) 17:05, 16 August 2012 (UTC)

Even if they are worried, there is patent pending. --Mr.98 (talk) 17:26, 16 August 2012 (UTC)

"I see his name on so many inventions, that Pat Pending must be a genius !" StuRat (talk) 13:46, 17 August 2012 (UTC)

There is no requirement that one have a patent before marketing a product, and marketing a product does not prejudice a patent application. Perhaps you would need a patent to sell or license the patent rights, but even then, negotiations could proceed before a patent has been granted. Are you just looking for statistics? μηδείς (talk) 17:13, 16 August 2012 (UTC)

They are looking for "data". --Mr.98 (talk) 17:28, 16 August 2012 (UTC)

μηδείς is only right when referring exclusively to the US. Marketing a product is considered a form of disclosure under most jurisdictions, and it is a hindrance to granting a patent. If you are serious about what you are doing get professional legal advise from a patent lawyer. Qpl87 (talk) 16:42, 17 August 2012 (UTC)

I've found it surprisingly difficult to dig up statistics on this, though I am sure it has been studied exhaustively, like most things patent-related. This paper offers a bunch of cherry-picked examples but shows a good way that such a study would be arranged (comparing earliest patent date with date of first sale/release of product), and may prove fruitful for more literature searches. The examples they pick show it is about 3 to 5 years, but I've no idea if that holds when looking at more data. --Mr.98 (talk) 17:26, 16 August 2012 (UTC)

Thanks, a lot! That's pretty useful even if it's not very comprehensive. I have found it surprisingly tricky to find data too. If anyone finds anything similar, let me know! Eiad77 (talk) 17:44, 16 August 2012 (UTC)

I think the reason it's so hard to find data linking the two is because they're not really linked. The company I work for is currently commercializing a new technology that the patents aren't issued for yet. In general, no one else can patent your discoveries, so as long as there's no risk that another company will start using it before you make an application, then you can take your time. Also note that even if your application is successful and the patent is issued, it has happened that a court has declared the patent overly broad and invalidated it. 203.27.72.5 (talk) 23:50, 16 August 2012 (UTC)

It doesn't matter if they're linked — it would still be interesting to know (especially across industries), and there are lots of context in which that information would be useful (e.g. evaluating the effect of a new patent granting on a future earnings potential of a given company). I think you're quite wrong about the time factor not mattering — it really depends on the industry. In big pharma for example the patent clock is not as long in practice as you'd think because of all the testing, and the minute it runs out there will be tons of generics out there. For those guys, the length of time before getting the drug on the market really translates into a lot of money. Anyway, I find it hard to believe this hasn't been studied. Business schools have dredged up data on practically every other patent statistic out there. It is a major field of research. --Mr.98 (talk) 00:37, 17 August 2012 (UTC)

Yes, you're right about it depending on the industry. I was thinking of engineering applications where the patent is only needed to secure your exclusive rights, not as a prerequisite for fulfilling regulatory testing requirements. 203.27.72.5 (talk)

I may be stating the blindingly obvious here, but if you are trying to determine an average for the time it takes "to go from patent to commercialization", the answer is either infinity, or at least not a meaningful number at all. The majority of patents are never "commercialized". Sadly, far too many people seem to think that a patent is a guaranteed route to profitability. I think you need to look at it backwards - if a patent proves successful, how much earlier on average was it taken out? AndyTheGrump (talk) 02:20, 17 August 2012 (UTC)

This is true. I realize that a very small percentage of patents are ever commercialized. I guess if I were to be really precise, the question I am asking is: "For patents which are commercialized, what is the average time period between when the patent is filed and commercialization?" Eiad77 (talk) 13:10, 17 August 2012 (UTC)

current

laser transmit the current? it's possible? — Preceding unsigned comment added by K.jayen (talk • contribs) 16:22, 16 August 2012 (UTC)

Yes, see electrolaser.  Card Zero  (talk) 17:09, 16 August 2012 (UTC)

Lasers emit light - electromagnetic waves - and an electromagnetic wave does not carry or move charge. In cases where the wave travels through a region with freely-moving charged particles, the wave and the charge can interact; a current could flow, depending on the situation. But there is a significant difference between a propagating electromagnetic field, and a propagation of electric charge - even if the two phenomena coincide and interact. In some unusual configurations, a laser may cause charge to flow - especially high power lasers that ionize the medium they're in, or are powerful enough to create a plasma by heating the air through which the beam is passes. These are exceptions, not the norm. Nimur (talk) 17:37, 16 August 2012 (UTC)

Perhaps relatedly: Beam-powered_propulsion#Electric_propulsion; Elevator:2010#Beam_Power_Challenge. --Mr.98 (talk) 17:43, 16 August 2012 (UTC)

magnet

iron or something material go to very cooling temperature it's act magnet? — Preceding unsigned comment added by K.jayen (talk • contribs) 16:29, 16 August 2012 (UTC)

You may be thinking of superconducting magnets, in which certain superconductive materials can become magnetic; or the related Meissner effect, where the material "repels" a magnetic field. The classroom example for this effect is usually a ceramic that has been cooled by liquid nitrogen, not iron; though modern investigations have found weak superconductivity effects in all sorts of materials. Nimur (talk) 17:42, 16 August 2012 (UTC)

Orange lights, other colors of LED lights

Because standard 3 lights, yellow lights, red lights, green lights, and white lights and blue lights, where is a common place you find orange LED lights. I heard about purple lights, but where will you likely to see purple LED lights. Is there such thing as brown LED lights or pink lights. I know the blue lights and the white lights well, I just want to know where will you see orange LED lights, is there even such thing as pink LED lights or brown LED lights? I heard they use purple LED lights at concerts, Olympics, where will I see purple LED lights. What other colored LED lights are there?--69.226.44.207 (talk) 20:35, 16 August 2012 (UTC)

The Wikipedia article Light-emitting diode#Colors and materials gives a list of colours and how they are produced. Some colours are more expensive to manufacture. I have some orange LEDs in Christmas lights. I don't know where you might see purple, violet or pink. Violet can be produced naturally, but purple, pink (and presumably brown, though I don't know why anyone would bother) have to be produced artificially by combining colours or adding phosphors, pigments or dyes. Dbfirs 21:39, 16 August 2012 (UTC)

Is amber lights (traffic lights) always yellow lights or is it orange lights. I have somebody told me some traffic lights are orange lights. I just see some traffic lights/ yellow lights look a little golden, I hardly think yellow lights/traffic lights actually look orange.--69.226.44.207 (talk) 23:14, 16 August 2012 (UTC)

Yes, most traffic lights are yellow, but I have seen a few that look rather orange. However, those aren't LEDs. (Does anybody make LED traffic lights ? I'm not sure they would be bright enough.) StuRat (talk) 03:40, 17 August 2012 (UTC)

Yes, in fact they are widespread. See Traffic light. 203.27.72.5 (talk) 04:48, 17 August 2012 (UTC)

I see. However, they don't get hot enough to melt off snow, which might explain why I don't see them here. StuRat (talk) 05:09, 17 August 2012 (UTC)

What a great lead question, I love it! Its like a poem on crack!165.212.189.187 (talk) 14:33, 17 August 2012 (UTC)

I'm not sure where you are Stu, but here in the Canadian Prairies all of the new traffic lights that go up are LED technology, and we nearly spend long enough covered in snow every year to forget what grass looks like. Sometimes a fresh snowfall can accumulate in a pile on the traffic lights on a calm day, but the actual lens is never obscured. BigNate37_(T) 08:03, 18 August 2012 (UTC)

Detroit. We often have road signs which become unreadable when compacted with snow, so I'm surprised this doesn't happen with the LED lights, if they can't melt it. Perhaps your version has a device specifically to heat it on cold days ? StuRat (talk) 09:15, 18 August 2012 (UTC)

Well our traffic lights have visors over each lens, and really that's more to shade the sun so they are somewhat visible even when in direct sunlight. Frankly I'm having trouble understanding how snow would accumulate on the lens in the first place, as they're a vertical (albeit slightly concave) surface. Perhaps it bears mention that our snow is almost always light, fluffy, and dry—when it remains well below freezing for weeks at a time, our snow doesn't stick together anyways (except where it is driven or trod on). We certainly don't have any kind of snow heating going on with our traffic lights or any other city property; that sounds dangerous, it would cause icicles to form above the street. BigNate37_(T) 09:58, 18 August 2012 (UTC)

The conditions that cause vertical signs to be compacted with snow are as follows:

1) It's been quite cold, typically overnight, so the signs are well below freezing.

2) A warm front moves in, bringing snow and raising the air temp to right around freezing. This gives us big juicy flakes that clump together and blow at an angle.

3) When those big flakes hit the face of the sign, they freeze to it, and accumulate, until the sign becomes unreadable. I'd expect the same thing to happen to cold traffic lights, although the visor might help a bit. Also, if slightly warmer, we get freezing rain rather than clumping snow, which can be even worse. StuRat (talk) 10:10, 18 August 2012 (UTC)

I see what you mean, something like [12]. Our metal street signs sometimes see this phenomenon, particularly on the larger ones like stop signs. I've literally never seen it afflict traffic lights, though. Perhaps glass lenses don't have the heat capacity to exhibit such phenomena. BigNate37_(T) 16:03, 18 August 2012 (UTC)

That might explain it. Or maybe they are heated. Note that the heat from traditional traffic lights didn't make them form significant icicles. Presumably the amount of snow that is melted is just insufficient to make much of an icicle. (You normally need a roof's worth.) Here's a pic of an LED light with small icicles, supporting the idea that they are heated: [13]. StuRat (talk) 18:47, 18 August 2012 (UTC)

As for a practical use, orange LEDs could serve as a warning indicator between yellow (don't worry about it) and red (evacuate to outside the blast radius immediately). StuRat (talk) 14:37, 17 August 2012 (UTC)

There is no such thing as a brown light. Brown is an artifact of the way the human visual system interprets color in a scene. You can't make a brown spotlight.--Srleffler (talk) 06:21, 18 August 2012 (UTC)

Yes, brown is more of a reflective colour. Pigments and dyes can look brown in reflected light, but it is difficult to get light to look brown when shone through them since almost all of the light will be absorbed. It would be possible to have an LED indicator that looked brown, but not a spotlight that made everything it shone onto look brown. Dbfirs 07:28, 18 August 2012 (UTC)

What are all of you talking about? Brown is simply a negative "luminosity" of orange (where -1 is black, and +1 is white), or dark orange. A brown LED is simply a low power orange LED. Plasmic Physics (talk) 07:54, 18 August 2012 (UTC)

I call that "dark orange" rather than "brown" but perhaps it is just a matter of perception. We all see colour differently. Dbfirs 08:09, 18 August 2012 (UTC)

Yes, PP has a nonstandard def of brown. Here's a page which lists the RGB values for orange as 255,165,0 (no blue) and brown as 165,42,42 (as much blue as green): [14]. StuRat (talk) 09:22, 18 August 2012 (UTC)

Of course, that RGB coordinate represents perfect brown, brown covers the domain of [Hue, Sat, Lum] = [0 < x < 40, 0 < y ≤ 240, 0 < z <120]. Plasmic Physics (talk) 10:58, 18 August 2012 (UTC)

A good example of brown could be [Hue, Sat, Lum] = [20, 240, 60] ≡ [R, G, B] = [128, 64, 0]. Plasmic Physics (talk) 11:02, 18 August 2012 (UTC)

Cultural impact of extraterrestrial contact

Cultural impact of extraterrestrial contact

In reading this Wiki article, please explain to me in layman's terms the following:

"Moreover, humans may be an unsuitable food source for extraterrestrials because of marked differences in biochemistry.[3] For example, the "handedness" of molecules used by terrestrial biota may differ from those used by extraterrestrial beings.[39]"

I'm confused by the phrase "Handedness of molecules" Reticuli88 (talk) 20:52, 16 August 2012 (UTC)

It's referring to chirality. Molecules that have the same atoms, but in mirror image arrangements (labeled "right-" and "left-handed"), can behave differently in chemical reactions. Clarityfiend (talk) 20:56, 16 August 2012 (UTC)

How will that affect the extraterrestrial, in layman's terms please?Reticuli88 (talk) 20:59, 16 August 2012 (UTC)

It depends. Some molecules may simply be indigestible, making us good diet food. Others could be poisonous in various ways. See Thalidomide. μηδείς (talk) 21:02, 16 August 2012 (UTC)

It's a plot device that crops up now and again in science fiction stories. Beings stranded on otherwise habitable planets starve to death because the chirality (chemistry) is wrong. (Damon Knight and Rod Serling obviously thought otherwise with "To Serve Man" and "To Serve Man" (The Twilight Zone).) Clarityfiend (talk) 21:10, 16 August 2012 (UTC)

The best story of that ilk is Clarke's 1950 "Technical Error", where it makes a sort of sense, but that doesn't involve aliens. Wnt (talk) 09:23, 17 August 2012 (UTC)

also, please explain the bolded sentence:

::"According to Luca Codignola of the University of Genoa, contact with a powerful extraterrestrial civilization is comparable to occasions where one powerful civilization destroyed another, such as the arrival of Christopher Columbus and Hernán Cortés into the Americas and the subsequent destruction of the indigenous civilizations and their ways of life.[2] However, the applicability of such a model to contact with extraterrestrial civilizations, and that specific interpretation of the arrival of the European colonists to the Americas, have been disputed.[78] Even so, any large difference between the power of an extraterrestrial civilization and our own could be demoralizing and potentially cause or accelerate the collapse of human society.[39] Being discovered by a "superior" extraterrestrial civilization, and continued contact with it, might have psychological effects that could destroy a civilization, as is claimed to have happened in the past on Earth.[21]" Reticuli88 (talk) 21:31, 16 August 2012 (UTC)

I've skimmed the cited article; the author mentions no claims of actual extraterrestrial contact. The author discusses contact between human civilizations and their often disastrous consequences. The sentence is just poorly worded. Clarityfiend (talk) 22:01, 16 August 2012 (UTC)

See also Cargo cult and European colonization of the Americas, which I have added to the article. μηδείς (talk) 22:29, 16 August 2012 (UTC)

I think a much better example for the article would be if the extraterrestrial's biochemistry was based on a solvent other than water. Imagine biting into an apple that was 90% ammonia. 203.27.72.5 (talk) 00:12, 17 August 2012 (UTC)

See Flast the Cryon in Attack of the Cybermen. μηδείς (talk) 00:57, 17 August 2012 (UTC)

The Way to Eden... Wnt (talk) 09:30, 17 August 2012 (UTC)

Advanced civilizations may well consist of self-replicating robots, and they could eat the entire Earth. Count Iblis (talk) 02:53, 17 August 2012 (UTC)

For that, see Greg Bear's The Forge of God and its sequel, Anvil of Stars. μηδείς (talk) 03:01, 17 August 2012 (UTC)

I don't know if pointing out where a theme was referenced in science fiction everytime someone brings one up is what we mean by "science reference desk" :P 203.27.72.5 (talk) 03:22, 17 August 2012 (UTC)

The earlier Berserker (Saberhagen) series was better, IMHO. Wnt (talk) 09:36, 17 August 2012 (UTC)

The idea of aliens using people for food or slaves seems rather absurd to me. Any technology that can move the extraterrestrials from one solar system to another in a reasonable time frame could also produce food in abundance and do all their work for them. The way alien contact could be negative, IMHO, is if they want the Earth, to colonize, and we get in their way, or if they see us as a potential future threat, so decide to exterminate us. StuRat (talk) 03:47, 17 August 2012 (UTC)

Surely, you don't mean that any interstellar travel technology is also necessarily a food sythnesis technique? 203.27.72.5 (talk) 04:45, 17 August 2012 (UTC)

No, I mean that any civilization with near-light-speed-travel can probably handle hydroponics, at the very least. Oh, and don't call me Shirley. :-) StuRat (talk) 05:12, 17 August 2012 (UTC)

I think that when we look at attempts to model 'pushy' aliens, like Childhood's End or The Day The Earth Stood Still, it is obvious that aliens capable of understanding Earth culture enough to take sides would absolutely be resented and their power would be seen as an enslavement. Of course, what is very difficult indeed for such novels to impart is the depth of knowledge in support of their positions, and the wisdom of the positions, that real aliens of a superior civilization might actually have. Nonetheless, it is quite plausible that aliens seeking to elevate human culture rather than oppress it would elect a tactic of inspiring certain individuals along the line of Jesus or Laozi to provide seminal ideas which, they would plan, would eventually bring about the desired ideological development with less disruption. Of course, then again, not making contact quickly also involves disruption, perhaps even lethal disruption for the planet (itself a common sci-fi motif...) Wnt (talk) 09:44, 17 August 2012 (UTC)

I've always been puzzled by 2001: A Space Odyssey, where the "helpful alien obelisk" apparent inspires chimps to murder each other, rather than, say, to work together for the common good. StuRat (talk) 15:58, 17 August 2012 (UTC)

Actually, given the history of colonialism and decolonization, I suppose it's not unrealistic. :( Wnt (talk) 23:43, 17 August 2012 (UTC)

SPOILER WARNING!!! It was intentional. The monoliths were neutral machines and thus didn't exactly influence the apes to kill each other. It was simply human/ape nature. This was underscored by the match cut of the jawbone thrown to the sky transforming into an orbitting satellite. The novel explains this in the finale, but the lack of narrative and the removal of the star child final scenes in the film makes it unclear. Those satellites are actually orbiting weapons platforms with nukes. A bigger stick. Explained even further in the later books of the series where when the monolith's controllers upon receiving the "evaluation" sent back by the Earth monoliths (unfortunately during World War II), decided to destroy humanity even though human society had outgrown that violent period by the time (~3000 AD) that response was received by the Solar System monoliths and the HAL-Bowman star child. -- OBSIDIAN†SOUL 00:42, 18 August 2012 (UTC)

August 17

what's the squiggly side group symbol stand for?

See the structural diagram for Methamphetamine. What does the squiggly side group stand for? μηδείς (talk) 00:47, 17 August 2012 (UTC)

See skeletal formula to learn what a bond being a wavy line means. DMacks (talk) 00:52, 17 August 2012 (UTC)

Thanks, that gives a general answer of unknown or stereoisomer. In this case its obviously a stereoisomer of some chiral sidegroup. Can anyone specify it? μηδείς (talk) 01:02, 17 August 2012 (UTC)

The active form is dextrorotary, which in this case is "out of the screen". Bizarrely, Levomethamphetamine is also drug, but functions only as a decongestant. Someguy1221 (talk) 01:05, 17 August 2012 (UTC)When I wrote this comment, I thought you were asking which isomer it was, not which sidegroup it was. Someguy1221 (talk) 01:17, 17 August 2012 (UTC)

So, the squiggly side group is a methyl group. Is that what you're asking? 203.27.72.5 (talk) 01:10, 17 August 2012 (UTC)

That it is a methyl group is clear from this image. 203.27.72.5 (talk) 01:14, 17 August 2012 (UTC)

Otherwise unannotated squiggly lines are always methyl groups, just as otherwise unannotated straight lines are always methyl groups. Someguy1221 (talk) 01:16, 17 August 2012 (UTC)

Okay, so it's a methyl group and a hydrogen then, since a methyl alone would require a missing double bond. Makes sense. I don't remember the squiggly side group. When did that convention come into style? I remember a wedge perhaps next to a line, or an R. μηδείς (talk) 01:19, 17 August 2012 (UTC)

The wedges represent specific isomers. The squiggle represents a racemic mixture. And if it is a methyl group there must be a hydrogen. If there were a double bond it would not be a methyl group. See methyl group. 203.27.72.5 (talk) 01:23, 17 August 2012 (UTC)

It occurred to me that you might mean a double bond like this; R-CH=C(CH2)R, rather then like this; R-CH2-CH(=CH2)R as I first assumed. If that's the case then the methyl group would still be indicated by a line even though there's no hydrogen there. So the line doesn't represent the hydrogen as well, just the CH₃. The hydrogens are ommited by convention. 203.27.72.5 (talk) 01:45, 17 August 2012 (UTC)

Yes, I did mean what you first assumed, 203. And at this point I fully get what is symbolized for this specific molecule. And I agree that there would have to be a hydrogen for the remaining side group if none other were signified. My point is, I do not remember the squiggly mark from Organic Chem when I tested in or took it. For the Bio part of my undergrad double-major I tested out of OC lecture in the early nineties. (Before that I got A's in Chem I & II and Biochem in high school and a V on the AP test.) And I aced organic chem lab when I finally took it in the mid nineties. I simply do not remember the squiggly convention. Should it be interpreted as any stereoisomeric sidegroup? (Any old racemic mixture?) And when did the squiggly convention begin? I am concerned that I had an Ivy League education with a sub-par Org Chem class. μηδείς (talk) 02:45, 17 August 2012 (UTC)

To quote the page I pointed you to earlier, "wavy lines represent either unknown stereochemistry or a mixture of the two possible stereoisomers at that point". I know I've seen it in literature from at least back to the mid-1980s, but I don't know the history of IUPAC or others officially blessing it. DMacks (talk) 03:14, 17 August 2012 (UTC)

Here it is being used in 1989, so it at least predates your college days as far as I can see. To be fair though, I don't think it was ever explicity pointed out by my lecturers when I was at uni, and I majored in chem. It was just something I picked up on from seeing examples where that was the only possible meaning. 203.27.72.5 (talk) 03:17, 17 August 2012 (UTC)

I found these [15] [16] [17] earlier examples but they all seem a bit odd to me. I'm not 100% sure that they're using the squiggly line in the same way that we do these days. 203.27.72.5 (talk) 04:42, 17 August 2012 (UTC)

I made the change to methamphetamine and someone quickly pointed out that the squiggle actually just means undefined, not racemic in any particular ratio. I should have thought of that, but I'll point it out now. Wnt (talk) 16:27, 17 August 2012 (UTC)

I very highly doubt the textbook edition I used in '90 that had been published in 1987 or 1989 was using a convention that we cannot find much prior to that date--textbooks tend to be conservative. I will accept this question as resolved. μηδείς (talk) 07:02, 18 August 2012 (UTC)

Resolved

ET contact book

The question above about extraterrestrials reminded me of a book I read about on Wikipedia, and that I'm hoping someone could identify. The plot is that an enormous alien spacecraft has entered the solar system on a fast hyperbolic trajectory. Due to celestial mechanics, the only human spacecraft capable of docking with it is piloted by a young girl on her first solo flight (an average Joe in some ways), but her ship wouldn't have enough fuel to return to the solar system. The rest of the book describes her exploration of the mysterious artificial ecosystem inside the alien craft, which apparently had water, but many other features were extremely bizarre and non-Earth-like. At the end, there was no cheesy cop-out, and the girl did starve (or die some other way) on board, but the book was really more about the alien craft than about the explorer.

Before anyone mentions it, this is not Rendezvous with Rama (which is a great book, by the way; I highly recommend it). It seems to share a similar plot, but then again there are millions of books about aliens out there. --68.179.115.177 (talk) 06:43, 17 August 2012 (UTC)

Yeah Rendezvous with Rama was my first thought. I'd love to know too, sounds like a great read.-- OBSIDIAN†SOUL 07:29, 17 August 2012 (UTC)

I found something like it. Pushing Ice by Alastair Reynolds. Though in this case, it was an entire crew of a mining ship, but the captain is still female.-- OBSIDIAN†SOUL 09:32, 17 August 2012 (UTC)

The description reminds me somewhat of a short story by James Tiptree, Jr. It may have been the lead title (and certainly inspired the pbk cover illustration) of one of her short story collections, but I'm afraid I can't remember which and, being at work, can't consult my library. Hopefully this might give someone a helpful lead. {The poster formerly known as 87.81.230.195} 84.21.143.150 (talk) 12:57, 17 August 2012 (UTC)

[Later] False lead, mea culpa. I was misremembering "The Only Neat Thing to Do", whose plot is not close enough to that sought to be a candidate. {The poster formerly known as 87.81.230.195} 90.197.66.109 (talk) 21:15, 17 August 2012 (UTC)

Which jobs require sharp vision?

I am endowed with exceptionally sharp vision, which enables me among else to read signs from a long distance. My motor skills are normal, and not as developed as those of an air pilot or a sniper. Which civilian jobs require sharp vision, besides relevant academic education? Thanks, 93.172.151.222 (talk) 10:36, 17 August 2012 (UTC)

Something in forensics, maybe? I don't think there are really many jobs where better than normal vision is particularly useful. --Tango (talk) 12:10, 17 August 2012 (UTC)

Off the top of my head: On the floor of the stock exchange; Any captain of a passenger vehicle (cruise ship, airliner, bus, etc.); Operator of heavy machinery (crane, bulldozer, etc.); Janitor; Quality control.165.212.189.187 (talk) 15:55, 17 August 2012 (UTC)

Private eye ? There one particular vision skill is needed, at which I seem rather deficient: facial recognition. (I can only recognize people in context. If I met my mother someplace unexpected, and she didn't talk, I wouldn't recognize her.) StuRat (talk) 15:54, 17 August 2012 (UTC)

That sounds like as a disability. Qpl87 (talk) 16:07, 17 August 2012 (UTC)

In general (not commenting on any one case) I suspect that prosopagnosia, or more properly prosopamnesia, is uncommonly common on Wikipedia...^[18] Wnt (talk) 16:49, 17 August 2012 (UTC)

Cool, so now I can get a handicapped sticker and park up front. :-) StuRat (talk) 16:51, 17 August 2012 (UTC)

Olympic archery champion. --TammyMoet (talk) 16:55, 17 August 2012 (UTC)

I'd say referee, but maybe sharp vision there would be a handicap. :) Also the security freaks who watch people at casinos and such? Wnt (talk) 17:10, 17 August 2012 (UTC)

Airline pilot? Sniper? Sniper spotter? 203.27.72.5 (talk) 21:15, 17 August 2012 (UTC)

Congratulations on your excellent vision, (this is from a resentful myopic) but I can't help noticing that all the occupations suggested need a good many other skills apart from good vision. Your exceptional visual acuity needs to be combined with sound judgement, knowledge, morality and experience, gather those 4 friends around you and you are on your way. Richard Avery (talk) 06:39, 18 August 2012 (UTC)

physics/5th Dimension

I don't understand what is defined as 5th Dimension ? I know the space and time is considered as Third and Forth dimension, but not sure about Fifth one? What the picture shows actually ?How can we observe/feel the 5th dimension?

--Kesavan (talk) 13:09, 17 August 2012 (UTC)

First off lets pretend we are 2D (length and width) beings on the surface of a balloon (here time is the 3rd dimension). A spot on the other side of the balloon is a distance away, as we have to stick to the surface of the balloon. However, as we have 3 spacial dimensions (and a time dimension) to work with, we can take a "short cut" though the centre of the balloon, shortening the distance between the 2 points. So this is one way a 4th spacial dimension would revel itself, particles arriving at places sooner than expected. A second time dimension I'm not sure on how that would appear Dja1979 (talk) 14:38, 17 August 2012 (UTC).

This diagram, by itself, does not contain any useful information. It is part of a longer paper letter-to-the-editor-of-a-physics-journal, On the dimensionality of spacetime, available from its author's website: Max Tegmark, professor of Physics at MIT. Have you read his paper? It explains the author's views about space and time. In my opinion, these views are not particularly rigorous, nor are the explanations of the assumptions particularly sound; but, nobody other than the author is responsible for his reasoning. Nimur (talk) 17:18, 17 August 2012 (UTC)

"we are here " seems to me to be a bit short sighted because it only refers to our physical selves. When I look at the three dimensions of time and one of space I think of past, present and future, then I think what can travel in these dimensions? A: thoughts.... my thoughts can travel back in time and recall real events and that "information" since it is obviously not lost is still "somewhere" in my head. So is that information traveling ahead into the future to meet my consciousness in the present? Or do I have some intrinsic ability to travel at least in one dimension of thought to the past?GeeBIGS (talk) 02:39, 18 August 2012 (UTC)

when I think of one dimension of both space and time I think of light, two dimensions of space and one of time I think of the plane between positive and negative charge in a magnet, one dimension of time by itself or space without the other is like a singularityGeeBIGS (talk) 02:48, 18 August 2012 (UTC)

Approximately how much mass does the Milky Way lose each day?

Due to stars radiating energy into extragalactic space. Assume no mass is being gained from external sources. Goodbye Galaxy (talk) 14:22, 17 August 2012 (UTC)

and I just realized how appropriate my username is for this question

Since you ask only about radiated light, this is an easy calculation. Orders of magnitude (power) claims that the Milky Way radiates 5×10³⁶ W (though it doesn't cite a source). Divided by c², that's 5×10²⁴ kg/day. -- BenRG (talk) 18:02, 17 August 2012 (UTC)

Which is remarkably close to the mass of Earth. That seems very small to me... just goes to show how big the speed of light is, I guess. --Tango (talk) 19:35, 17 August 2012 (UTC)

Ok, but how much does it recieve each day from intergalactic space? SkyMachine ⁽⁺⁺⁾ 03:39, 18 August 2012 (UTC)

Since the Galaxy is mostly empty space, I imagine that most mass "received" simply passes right through and keeps going. Someguy1221 (talk) 03:47, 18 August 2012 (UTC)

The net balance is ~zero, but can anyone estimate the daily incoming energy transaction? SkyMachine ⁽⁺⁺⁾ 03:53, 18 August 2012 (UTC)

Is an apple alive or dead when you eat it?

Three questions in one:

1. At the instant before you take the first bite of an apple is it considered alive or dead?

2. At any moment during consumption of an apple is it considered alive or dead?

3. After you've finished eating an apple, is the remaining apple core considered alive or dead?

Thank you for your time. — Preceding unsigned comment added by Wallywalrus (talk • contribs) 15:43, 17 August 2012 (UTC)

It's difficult to define alive or dead in plants. I will use the definition "it is alive if it can grow a new apple tree". In that case, the apple, or more specifically the seeds, are still alive after all three steps (assuming the seeds were viable to begin with). In fact, even if you ate the seeds, they might still be viable after you poop them out. StuRat (talk) 15:49, 17 August 2012 (UTC)

(ec) Technically one could say the apple is alive, in the sense that it can produce an apple tree. However, the only 'living' part are the seeds, the rest of the apple is actually food meant to be eaten, because when animals eat the apple, they unintentionally spread the seeds around, to the advantage of the apple tree that produced the apple. Certainly by eating an apple you do not 'kill' it, afterwards it has not lost its ability to grow (and eventually reproduce). - Lindert (talk) 15:51, 17 August 2012 (UTC)

What are alive in any organism are its cells. A fruit (excluding its seeds) is not an organism, but a part of one. The skin of an apple consists of live photosynthesizing cells which allow it to grow and produce various oils and pigments as the fruit matures. They remain living for some time after the fruit matures. There is not very much I can find at wikipedia, but see pome and exocarp. μηδείς (talk) 17:52, 17 August 2012 (UTC)

In multi-cellular animals, the organism can be dead even when most of its cells are still alive. This would be the case, for example, right after somebody was beheaded. Some of the cells with low metabolic rates (like those which grow hair), can stay alive for quite some time. However, with plants, there really isn't this distinction between the life of the cells and the organism. The plant is basically "just the sum of its cells". StuRat (talk) 18:02, 17 August 2012 (UTC)

Snopes and other debunkers deny old stories of fingernails and hair continuing to grow after death. When you die, your hair and fingernail production stops, but the flesh may dehydrate, exposing more of the hair or nails. Edison (talk) 03:03, 18 August 2012 (UTC)

Yes, but those cells don't die the very second your heart stops. StuRat (talk) 03:06, 18 August 2012 (UTC)

If they did, organ transplants wouldn't be possible. Organs such as hearts, livers, and kidneys can "survive" for several hours outside the body, if treated properly.Sjö (talk) 06:51, 18 August 2012 (UTC)

And a fruit is not an organism, so there is no sense in asking if it, as opposed to some of its parts, is alive. The apple is not alive as such, but many of its cells are, for quite a long time. So long as the skin is both open to air and not brown or frozen you should view its cells as alive. μηδείς (talk) 06:56, 18 August 2012 (UTC)

But, as previously explained, the concept of an organism being alive or dead, as opposed to the cells, only applies to multi-cellular animals. So, asking if an apple tree is alive is about the same as asking if an apple is alive. With plants, perhaps asking "Is it still viable ?" would be the better question. StuRat (talk) 07:02, 18 August 2012 (UTC)

You could use that terminology, in which case apple skin itself is not viable, even though it can be cultured in a lab and produce a thallus. Otherwise the seeds, which are usually considered distinct, and not consumed, would be the only part normally considered viable. Given that the seeds are not eaten, but the skin is, and it is alive, I would stick with yes as the answer. μηδείς (talk) 07:13, 18 August 2012 (UTC)

Different magnets

Is there an article in here about non-metallic magnetic materials? Is it possible to make a magnet which would repel the Earth? Is is possible to have a "laser" magnet? — Preceding unsigned comment added by Qpl87 (talk • contribs) 16:01, 17 August 2012 (UTC)

Plastic magnet is about non-metallic magnets. To repel the Earth an enormous and very heavy magnet would be required, but theoretically it is possible. I'm not sure what you mean by a 'laser magnet'. - Lindert (talk) 16:10, 17 August 2012 (UTC)

By "laser" magnet, I meant a magnet that instead of having a round field, would have a narrow field, concentrating its force on one point. Qpl87 (talk) 16:27, 17 August 2012 (UTC)

No, unless a magnetic monopole is discovered, magnetic fields are necessarily round, because according to Gauss's law for magnetism, total magnetic flux into any volume is zero. - Lindert (talk) 16:46, 17 August 2012 (UTC)

And why is a magnet that repels the Earth necessarily enormous and very heavy? According to your link polymers can be magnetic, so theoretically, should it be possible to construct a light-weight plastic magnet that would float around? Qpl87 (talk) 16:49, 17 August 2012 (UTC)

Yes, but to mainly repel the Earth instead of being repelled by it, it would need a lot of mass. If you are not concerned about getting the Earth moving, but moving away from the Earth, I guess you might use a lighter magnet. Anyway, I highly doubt any permanent magnet can be created in practice that is more repelled by the Earth's magnetic field than it is attracted by the Earth's gravity. - Lindert (talk) 17:09, 17 August 2012 (UTC)

Well any magnet can repel the Earth, it just can't repel it very much. :) Wnt (talk) 17:12, 17 August 2012 (UTC)

Technically, they repel each other by an equal amount, but, of course, the more massive object moves far less. StuRat (talk) 18:11, 17 August 2012 (UTC)

Magnetic fields are not "necessarily round", Gauss's law only states that the total flux through a closed surface is zero. See: Halbach array, Maxwell coil.—eric 18:19, 17 August 2012 (UTC)

Not round in the sense of prefectly circular, but magnetic field lines always form a loop (like in the Halbach array). - Lindert (talk) 18:26, 17 August 2012 (UTC)

So, back to the OP's question, yes, it is possible to have a narrow magnetic field, but I wouldn't describe such a field as a "laser magnet". 203.27.72.5 (talk) 20:49, 17 August 2012 (UTC)

This is all a bit dubious. The north poles of two magnets repel and likewise the south poles do the same. But if a magnet was sufficiently powerful that it could levitate by it's north pole repeling the earth's south pole, the magnet's south pole would be so attracted that it would change it's orientation towards the earth. You would need some mechanism to constantly keep the magnet in a particular orientation. If you want to achieve leviation, you'd be better off exploiting the Meissner effect with a superconductor, though I don't understand enough about this to know if it would ever work. 203.27.72.5 (talk) 20:44, 17 August 2012 (UTC)

Theoretically, if two magnets are perfectly aligned, neither should flip. However, placing a shaft between the two magnets will ensure that they don't (or just through the magnet you want to levitate above the Earth, stuck into the ground). StuRat (talk) 20:49, 17 August 2012 (UTC)

That's incorrect. See Earnshaw's theorem. 203.27.72.5 (talk) 03:19, 18 August 2012 (UTC)

There's no reason the alignment shaft shouldn't work. See Pseudo-levitation#Mechanical_constraint_.28pseudo-levitation.29. As for getting it to work without a mechanical constraint, that can be done with diamagnetism. StuRat (talk) 05:53, 18 August 2012 (UTC)

Yes, that part is alright, but "Theoretically, if two magnets are perfectly aligned, neither should flip." is wrong. And as for diamagnetism, that' exactly what I was suggesting with superconductors. 203.27.72.5 (talk) 07:46, 18 August 2012 (UTC)

That part is also fine, so long as one is a diamagnetic, so I'm not sure what you're disagreeing with. StuRat (talk) 10:18, 18 August 2012 (UTC)

I suppose you could do it with a gyroscope, or a very small motor with fast-reacting computer control, but by what margin would we need to improve on existing magnets to get one that levitates in this way? Wnt (talk) 23:40, 17 August 2012 (UTC)

You could make a blimp that's just slightly heavier than air, including an electromagnet, then use the electromagnet to lift off the ground. I don't see this being a very practical means of transportation, though. StuRat (talk) 02:06, 18 August 2012 (UTC)

Apparently, even that wouldn't work. See [19]. I tried to calculate the field strength of a magnet that would be required to cancel out the force of gravity, but I ran into...er...complications. 203.27.72.5 (talk) 03:59, 18 August 2012 (UTC)

And would it work if you weren't near one of the poles? 203.27.72.5 (talk) 02:01, 18 August 2012 (UTC)

Not as well, no. StuRat (talk) 02:06, 18 August 2012 (UTC)

Invisibility

Is there any scientific theory that could potentially cloak objects or is that something that will be confined to sci go & Harry Potter. For example, could destructive interference of visible light be used? — Preceding unsigned comment added by Clover345 (talk • contribs) 16:13, 17 August 2012 (UTC)

Even if you destroy the light that is reflected by an object, you still would be able to see it, unless you reconstruct the light rays that would be going through the place this object is occupying, if it were not there. Qpl87 (talk) 16:35, 17 August 2012 (UTC)

Yes, invisibility is theoretically possible. They've even done it in a very limited sense. You can either bend light around an object to hide it, or you can have cameras on one side of the object record the image on that side, and a screen on the other side display that (this only makes it invisible from one POV, however). Or, of course, an object can be made of transparent materials, if that counts. StuRat (talk) 16:39, 17 August 2012 (UTC)

The articles about the state of the art in invisibility: Transparency and translucency, and camouflage. Qpl87 (talk) 16:47, 17 August 2012 (UTC)

There was an even better article, but I can't seem to find it for some reason... StuRat (talk) 04:56, 18 August 2012 (UTC)

See Metamaterial cloaking, Adaptiv, Cloak_of_invisibility#Cloaks_of_invisibility_in_science and Active_camouflage#In_research. 203.27.72.5 (talk) 05:38, 18 August 2012 (UTC)

Invisiblity is quite possible, current research have achieved near perfect invisibility using metamaterials to refract and reflect ambient light around an object. However, it has its limitations - currently, it only works in the microwave range, and on the microscale. IMHO, these are more technological limitations than scientific limitations. Plasmic Physics (talk) 05:47, 18 August 2012 (UTC)

Meaning "...more technological limitations than theoretical scientific limitations." StuRat (talk) 18:35, 18 August 2012 (UTC)

Tinned pineapple poisoning?

Please note, this isn't a request for medical advice - I've already 'advised myself' to take it easy, and see a doctor if it doesn't resolve itself soon, though I'm already recovering rapidly. In any case, this is only a hypothesis, and "don't eat it if it tastes off" is hardly medical advice - doh!

Could tinned pineapple in a leaky can ferment sufficiently to cause 'food poisoning like' effects without making the contents look inedible? Having consumed a tin of the stuff on wednesday evening that at the time I thought tasted a little odd, I found myself a few hours later feeling distinctly queasy, and by the following morning I was projectile vomiting spectacularly. Initially I thought that perhaps I was coming down with gastric flu, but given that I'm now almost recovered, this seems unlikely. So, purely hypothetically, could such effects result from a leaky pineapple tin? Could the contents ferment, and would it produce the quantities of alcohol(s) sufficient to bring about the results described? It doesn't strike me as an obvious breeding ground for food-poisoning type bacteria etc. I've found a little on the subject via Google, but it is all rather anecdotal. AndyTheGrump (talk) 16:21, 17 August 2012 (UTC)

It could certainly cause food poisoning, but not from alcohol. The bacteria consumed and/or their toxins would be the cause. If it tastes or smells "off", don't eat it (it may not look rotten until later). If the can has lost it's seal, don't eat it (the lack of the suction sound of the vacuum breaking when you open it clues you in to this). StuRat (talk) 16:46, 17 August 2012 (UTC)

I'm not sure whether botulism couldn't grow in tinned pineapple. The USDA says that it is limited to low-acid vegetables [20], but I see an anecdotal forum report claiming otherwise [21] ... I don't know what I believe. There's no law of nature that says a bacterium can't learn how to resist acid, and doesn't have any strains that can. Obviously other bacteria are possible. But so are food allergies, or an unrelated cold. Wnt (talk) 17:07, 17 August 2012 (UTC)

I've seen plenty of moldy citrus, so it certainly is possible. I've noticed that it looks quite different on the outside of the moldy fruit, where you get furry bits of white, versus inside, where it tends to just get dark and mushy. Was the pineapple dark and mushy ? StuRat (talk) 17:33, 17 August 2012 (UTC)

No - it looked fine. AndyTheGrump (talk) 18:00, 17 August 2012 (UTC)

I once found a jar of apple sauce, looked fine, was unopened, tasted alright, and was free, so I ate it. Later that night I was not feeling well at all - the apple sauce expired 6 years previous... can't always trust your nose/tongue. 65.95.22.16 (talk) 19:44, 17 August 2012 (UTC)

Spider identification

Spider for identification

What type of spider is this? I haven't been able to find any good information on how you're supposed to measure spiders, but I did include a best-effort photograph of a ruler in this composite picture. I'd say its length sans-legs is roughly 15–20mm. It was found in southern Saskatchewan, if that helps narrow it down.

As a follow-up question, I'm wondering whether my amateur pictures are worth uploading to commons in a less compressed form; although that's probably a help desk question, if anyone has an opinion feel free to voice it. The three shots on the top of my composite picture here are the best ones I got, and I have hi-res un-cropped versions of them, but I have my doubts as to the value of the photographs. BigNate37_(T) 18:04, 17 August 2012 (UTC)

It's an orb-web spider, but that's not narrowing it down that much - perhaps an Araneus of some kind, such as the barn spider. Mikenorton (talk) 18:07, 17 August 2012 (UTC)

Wow, I actually saw the barn spider article soon after you mentioned orb-web spiders, but I didn't pay it much thought until you mentioned it explicitly. Upon closer examination, it may well be a barn spider, though several of the images at commons:Category:Araneus cavaticus look quite a bit different. Those listed at http://www.iowavoice.com/2009/09/13/barn-spider/ bear a lot more similarity. Thanks for taking a look, Mike. BigNate37_(T) 18:38, 17 August 2012 (UTC)

The markings are unclear but it may also be the female bridge spider (or gray cross spider, see commons:Category:Larinioides sclopetarius), another orb-weaver and notable for being synanthropic (living in human habitations). Also the difference you see in the commons pictures for A. cavaticus is merely sexual dimorphism. Your spider is very likely female, since they're usually the ones which build webs.-- OBSIDIAN†SOUL 00:02, 18 August 2012 (UTC)

I see. The body proportions and general posture of the limbs of my spider seem to match up better with the barn spider, but the habits fit the bridge spider better: she would hide behind a piece of the sheet metal on the spare tire frame during the daytime, and sat in the centre of her web after dark. BigNate37_(T) 00:18, 18 August 2012 (UTC)

Note though that the size of the abdomen varies depending on if the spider has recently fed or not. The pattern would be a better way to tell. For Larinioides sclopetarius see [22]. For Araneus cavaticus, see [23]. It also looks very similar to the *other* barn spider, Neoscona crucifera, see [24]. The cross orbweaver (Araneus diadematus) is also another possibility, see [25].

One way to distinguish the four is that A. cavaticus has small "knobs" or "shoulders" on the front part of their abdomens, kinda resembling the cat-faced spiders (Araneus gemmoides). It also has curved shallow C-shaped or comma-like white patterns on the underside of their abdomens. L. sclopetarius also has elongated comma-shaped to quarter note-like white patterns on the underside but lack the "shoulders". N. crucifera has a broken L white patterns on the underside and also lack the "shoulders". A. diadematus are usually more colorful, have somewhat "squared-off shoulders", and have C-shaped white patterns on the underside as well as distinctive white cross patterns on the upper side of their abdomens.-- OBSIDIAN†SOUL 06:01, 18 August 2012 (UTC)

It not having been pointed out explicitly, Araneus cavaticus is the Barn Spider, the best known example of which is Charlotte, form Charlotte's Web. μηδείς (talk) 06:30, 18 August 2012 (UTC)

Archery Accuracy

I was once told that elite target archery can be more accurate than target pistol shooting - presumably only at standard competitive archery distances (70m in the Olympics), and presumably when neither sport uses optical aids. Is this true? ([[26]] mentions "...the excellent accuracy of modern [archery] equipment..." but I cannot find anything that compares the two sports' accuracy. Tom Haythornthwaite 19:34, 17 August 2012 (UTC) — Preceding unsigned comment added by Hayttom (talk • contribs)

Of course some archer can deliver his arrows more accurately than some pistol shooter. But I would imagine that for someone with no prior experience with either, accurately shooting the pistol would be easier than shooting a bow and arrow. I shoot mainly rifles myself, but I do shoot pistol too. I've used a bow and arrow maybe twice ever, and I remember it being very difficult. Within the handgun dispilines there's also a wide array of different classes that are not all as easy to shoot accurately as each other, and they don't all have the same intrinsic accuracy. A black powder pistol that fires a lead ball is intrinsically less accurate than a revolver firing a bullet due to the aerodynamic aspects. A double action revolver is harder to shoot accurately than a semi automatic pistol because as the trigger is pulled in the revolver it cocks the hammer which causes the gun to want to move due to the hammer's inertia. You don't have that problem in the semi-auto because the firing pin was already cocked by the recoil from the previous round, or for the first round you would have cocked it manually. 203.27.72.5 (talk) 20:30, 17 August 2012 (UTC)

It's good to get the perspective of an actual gun shooter. I suppose I really want to know about the relative accuracy of top competitive archers and shooters; if they were aiming at the same target under the same conditions (within competitive archery range) who would win? Tom Haythornthwaite 20:37, 17 August 2012 (UTC) — Preceding unsigned comment added by Hayttom (talk • contribs)

Well, I thought I would just compare the world record in archery against the world record in pistol shooting, but unfortunately the Olympic pistol event is over 50m and the Olympic archery event is over 70m, so it's hard to compare them. 203.27.72.5 (talk) 21:45, 17 August 2012 (UTC)

I teach some basic archery to kids and have been on courses where they talk about competition shooting. The standard competition archery "face" (archers have their own jargon) for FITA events at 50m is 80cm (32 in?)[27] with the "gold" (which scores 9 or 10) being 155mm (6 in) across. However the 50m pistol target is 50cm (20in) with the centre being only 50mm (1.9in) in size.[28]. Good archers do get pretty tight groups at 50 or 70m, but can't get too tight as the first arrows tend to obstruct the path of the later arrivals (although you can move sideways along the shooting line to try to minimize this problem). So based on the size of the target, I would say that the expectation is that pistols are going to be more accurate than bows. Alansplodge (talk) 00:02, 18 August 2012 (UTC)

Resolved

Thank you, Alansplodge. Tom Haythornthwaite 05:27, 18 August 2012 (UTC)

Adrenaline rush

How do adrenaline rushes counter stress. For example, many people claim activities such as roller coasters or parachuting help relieve stress? Aren't prolonged adrenaline rushes dangerous as it leads to elevated heart rates which means blood is pumped less efficienty around the body or is that only in people with existing heart conditions? Note this is not medical advice and I'm not asking for an answer which contains advice. Clover345 (talk) 20:52, 17 August 2012 (UTC)

Short term it can be good, just like in exercise, as it gets your heart pumping, etc. Also, faced with a real or simulated life-and-death situation makes things we normally stress about seem insignificant, at least for a while. StuRat (talk) 20:55, 17 August 2012 (UTC)

thanks but what is the actual reason these activities relieve stress without being harmful? Clover345 (talk) 21:38, 17 August 2012 (UTC)

I don't think that adrenaline rushes per se counter stress. For example, suppose you are locked in a room with a hungry bear. Each time the bear looks at you, you will get an adrenaline rush. They don't counter your stress, though, they accumulate to increase it. What counters stress in the examples you mentioned is more likely the pleasure associated with the experiences, manifesting itself as a dopamine rush. Looie496 (talk) 01:09, 18 August 2012 (UTC)

is there a source for where this notion that they relieve stress is coming from? I have sought and not found. μηδείς (talk) 04:44, 18 August 2012 (UTC)

Time Dilation Questions

I have been directed here by DVdm with regards to a comment that I made on the article Time Dilation. This is located at:

http://en.wikipedia.org/wiki/Time_dilation

The section of the article entitled “Simple inference of time dilation due to relative velocity” concludes by stating that Δt’ = γΔt where γ is the Lorentz factor.

I wrongly assumed that this equation was in error because I did not take the setup properly into account. (Out of context it reads that moving clocks run fast).

However, when I analyzed the proof in that section, I stated that the bottom drawing could not be Euclidean because there was relative motion between the rest observer O and the moving observer whom I will designate as O’.

DVdm stated that the analysis “…in this case is used in the context of a spatial vector triangle in the Euclidean geometry of a 2-dim strictly spatial schematic drawing”.

I do not understand his comment.

In my mind the following are problems with that statement:

1) If the problem is strictly spatial then Δt and or Δt’ are 0 and the conclusion that Δt’ = γΔt is trivial.

2) If one looks at the problem from the point of view of observer O (and ignores the fact that O’ is moving), then the conclusion that Δt’ = γΔt will not be valid because as DVdm has stated the conclusion is valid from the point of view of O’.

3) If one looks at this from the point of view of O’ then the mirrors are moving and I can not envision a way to see this as a Euclidean space. This in turn means that the Pythagorean Theorem is not valid. But the Pythagorean Theorem is critical to the proof.

I would appreciate any guidance you can give me on this matter.

Thanks. Emagnus3 (talk) 21:33, 17 August 2012 (UTC)

3) The validity of the Pythagorean theorem in this context is an assumption of the argument. To say that "the speed of light is constant" is to say that ${\sqrt {(\Delta x)^{2}+(\Delta y)^{2}+(\Delta z)^{2}}}/\Delta t$ is a constant (namely c) for straight-line motion, where x, y, z, t are coordinates defined by some inertial reference frame (a network of metersticks and Einstein-synchronized clocks).

2) Δt’ = γΔt is valid independent of reference frame, because all relevant reference frames are mentioned in the definitions of the variables. Δt and Δt' are elapsed coordinate times of frames O and O' respectively, and γ depends on the relative velocity of O and O'.

The argument is valid. It's fine to dislike it, though. I dislike it. It's superficially convincing because it exploits Euclidean/Newtonian intuitions, but special relativity shows that you shouldn't trust those intuitions. It's usually a bad idea to separate x, y, z from t in special relativity and pretend that you live in a quasi-Newtonian world with weird non-Newtonian "effects". -- BenRG (talk) 01:04, 18 August 2012 (UTC)

For what it's worth, an argument I like better starts from the assumption of "relativity of redshifts"—roughly that if two people are moving inertially away from each other in outer space, and they point identical radar speed guns at each other, both guns will report the same speed. See k-calculus. -- BenRG (talk) 01:27, 18 August 2012 (UTC)

Spacetime is still flat (ie it's a Minkowski space) in special relativity, so the Pythagorean theorem is valid. It's only when you start fiddling with the metric tensor in general relativity that you need to worry about how to take the norm. --99.227.95.108 (talk) 04:42, 18 August 2012 (UTC)

Microwave plastic ring

My new microwave, like all others that I have seen so far, has a plastic ring below the glass plate. This is a combination microwave oven and grill and I don't know if its secure to use the grill (400 F) with the ring inside. The manual neither says it's possible, nor that it's not. Is it safe to use it? Qpl87 (talk) 22:20, 17 August 2012 (UTC)

First, knowing the model of microwave might help. Second, keep in mind that accepting a wrong answer on this might result in your microwave bursting into flame. You may still want to contact the manufacturer, especially if no one can give you a referenced answer. Someguy1221 (talk) 22:40, 17 August 2012 (UTC)

It's difficult to say as it depends greatly on exactly what the composition of the ring is. Perhaps it's actually glass-ceramic like white casserole dishes? BigNate37_(T) 23:02, 17 August 2012 (UTC)

I'd play it safe and take the ring out. Does it even try to rotate while in grill mode ? StuRat (talk) 02:01, 18 August 2012 (UTC)

I have seen combination-Microwave ovens that rotate a grill in convection mode that sits atop the glass plate, and whose instructions specifically state to allow the grill to rotate. The design of the grill may make it obvious what was intended by the manufacturer. Someguy1221 (talk) 02:57, 18 August 2012 (UTC)

I don't have a source, but I do have a microwave, and the plastic ring is of heat-resistant plastic, and it only touches the glass plate at three very small rolling points that will not conduct enough heat to melt the plastic even if I run the oven 20 minutes, which I never do. μηδείς (talk) 06:26, 18 August 2012 (UTC)

Right, and that's why they don't melt in a normal microwave, but a 400° F microwave/grill is a different story. Presumably the plastic will eventually heat to 400 degrees to match the air temperature. The question is whether it can take that heat. StuRat (talk) 06:31, 18 August 2012 (UTC)

Well, contact the m'f'er is still the only valid response. μηδείς (talk) 06:36, 18 August 2012 (UTC)

August 18

Who is this beetle?

What is this lovely beetle? I found it on my front porch today, in Kernville, California. It's about an inch and a half long. --jpgordon^{::==( o )} 01:13, 18 August 2012 (UTC)

Looks like a potato beetle with inverted colors. Some variation, perhaps ? StuRat (talk) 01:58, 18 August 2012 (UTC)

It looks like a female ten-lined June beetle. Although its difficult to see how large its antennae are in the photos, it does not appear to have the large distinctive antennae of the males of this species. -Modocc (talk) 03:09, 18 August 2012 (UTC)

Yeah female. But it could be any of three easily confused and sympatric species of Polyphylla though - Polyphylla decemlineata, Polyphylla nigra, or Polyphylla crinita. There's a [highly technical] species key here, but different sources offer different contradictory diagnostics. -- OBSIDIAN†SOUL 06:59, 18 August 2012 (UTC)

Thanks! And indeed, I forgot to mention that this lovely beetle was "hissing" as described in the article. June beetle indeedle! --jpgordon^{::==( o )} 15:43, 18 August 2012 (UTC)

+9 oxidation state

Can any element take a +9 oxidation state? I heard somewhere on-wiki (now forgotten) that IrO₄⁺ would afford the best chance for +9. I also read that meitnerium may be capable of it.--Jasper Deng (talk) 02:49, 18 August 2012 (UTC)

Apparently spectra of Ir(IX) have been observed. 203.27.72.5 (talk) 04:13, 18 August 2012 (UTC)

The wikipedia article that you read it in was most likely Iridium#Compounds where it says, "it was reported in 2009 that iridium(VIII) oxide (IrO4) was prepared under matrix isolation conditions (6 K in Ar) by UV irradiation of an iridium-peroxo complex.". 203.27.72.5 (talk) 04:16, 18 August 2012 (UTC) Sorry, that's not the cation you're talking about. 203.27.72.5 (talk) 04:19, 18 August 2012 (UTC)

(edit conflict)But that is in an excited state, and therefore technically doesn't count here.--Jasper Deng (talk) 04:33, 18 August 2012 (UTC)

This might be where you read both of those things [29]. 203.27.72.5 (talk) 04:32, 18 August 2012 (UTC)

I read that one on-wiki.--Jasper Deng (talk) 04:33, 18 August 2012 (UTC)

Well that could have been meitnerium, which cites the article I did when it says, "The oxidation state +9 might also be possible for meitnerium in [MtO₄]⁺". 203.27.72.5 (talk) 05:00, 18 August 2012 (UTC)

I specifically recall the iridium-based cation.--Jasper Deng (talk) 05:04, 18 August 2012 (UTC)

The paper W203 cites was also mentioned in two previous ref-desk discussions on this topic. DMacks (talk) 17:46, 18 August 2012 (UTC)

Specialization related to identification of animal sounds

Is there any specilization dealing with identification of sounds by animals (in the context of animal husbandry). Who are the well known figures in this speciality area Would appreciate any help183.83.244.183 (talk) 07:57, 18 August 2012 (UTC)vsmurthy

There's bioacoustics (and the related ecoacoustics). Identification by sound is a large part of the work of bioacousticians (especially among ornithologists). I don't know of any subfields of those specializing in domesticated animals though, as the usual subjects are birds, marine mammals, fish, anurans, and insects. There's also zoosemiotics, the study of animal communication in general.-- OBSIDIAN†SOUL 10:18, 18 August 2012 (UTC)

Hi, I need help with this endocrionological equation

There is a link for a picture of it.

I have understood the more basic equations to it, but i have lost that one, and i have tried some times... it appears in chapter 1 of Greenspan's endocrinology textbook. please explain it to me, i must understand it. many thanks. 79.181.146.146 (talk) 09:44, 18 August 2012 (UTC)

What is John Money's intention?

In the definition of the evolutionary term "Phylism" (page 85) ? — Preceding unsigned comment added by 109.65.177.63 (talk) 10:24, 18 August 2012 (UTC)

Black hole = Center of mass?

I am just throwing out this intuitive idea , how about this:

Black holes are formed at the point where the center of mass would be for massive objects such as galaxy's and globular clusters.

The mass of the object causes the distortion of space/time at the point where the center of mass would be and hence a black hole (or perhaps only super massive black holes).

92.23.128.134 (talk) 11:14, 18 August 2012 (UTC)a-uk

The centre of mass may be a future black hole, but a black hole event horizon will not appear around the space that is empty. He potential energy will be lower at one of your masses. Graeme Bartlett (talk) 12:25, 18 August 2012 (UTC)

"He potential energy" = the energy only released by a male couch potato when his team scores a goal on the TV. StuRat (talk) 18:31, 18 August 2012 (UTC)

You may find the shell theorem interesting. As it shows, there isn't necessarily any gravitational field at the centre of an object. Black holes form because of a concentration of matter at a point, not because of matter distant from that point but centred on it. --Tango (talk) 13:54, 18 August 2012 (UTC)

Plant identification

Hi! Can anyone identify the plant in these photos? In the space of a couple months, it's taken over almost our entire garden. Wide Mid Close - Thanks very much! 77.97.198.48 (talk) 19:13, 18 August 2012 (UTC)