Wikipedia:Reference desk/Archives/Science/2012 January 10
Science desk | ||
---|---|---|
< January 9 | << Dec | January | Feb >> | January 11 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
January 10
[edit]Water-fueled car - Where are they?
[edit]We are getting starved of oil, with the Strait of Hormuz soon to be choked off.
Snopes claims that oil companies do not buy up patents to vehicles that save or even go off of oil-based fuels entirely. (Perhaps Snopes succumbed to a conspiracy of being paid to lie.)
The vid says "...in the very near future." 3 1/2 years would be stretching it.
Why don't we see them out on the streets everywhere today? If it's in the best interest for many governments worldwide to wean off of oil, why wouldn't they pump funding into this car's development?
Japanese Company Invents Water Fueled Car
--70.179.174.101 (talk) 00:24, 10 January 2012 (UTC)
- Water powered cars, according to the article you linked to, is a sort of a scam, with no real chances of working ever. Besides that, not all governments want to leave the oil economy behind. Just think about Kuwait, Saudi Arabia and such. — Preceding unsigned comment added by 88.9.214.197 (talk) 00:30, 10 January 2012 (UTC)
- I said many governments. Many ≠ all. --70.179.174.101 (talk) 01:25, 10 January 2012 (UTC)
- See water-fuelled car. You'd be hard put to find any sort of bullshit that we don't have an article about. Looie496 (talk) 00:32, 10 January 2012 (UTC)
- Where are they? They're nowhere. They're impossible. — Preceding unsigned comment added by [[User:{{{1}}}|{{{1}}}]] ([[User talk:{{{1}}}|talk]] • [[Special:Contributions/{{{1}}}|contribs]])
- What did you think you saw on the video? --70.179.174.101 (talk) 01:25, 10 January 2012 (UTC)
- The process of invention involves finding the materials you need. In this case, inventors of the car knew they needed a fuel source with a lot of potential chemical energy, and they tried some substances like that until they found one that worked well. (They tried things like Coal, wood, gunpowder, etc.)
- You can't work that process backwards. You can't say "We've got a lot of water. Let's use that!"
- Imagine you ran a pizza parlor and the price of pepperoni was getting too high. You could start looking for other toppings that were equally delicious, but you couldn't just say "Hey, rocks are basically free. I'm going to figure out how to bake a delicious rock pizza." APL (talk) 01:05, 10 January 2012 (UTC)
- (editing convlict) Did you watch the video? Here it is again! --70.179.174.101 (talk) 01:25, 10 January 2012 (UTC)
- I watched the video. It's a con. It's a fake. It doesn't work. My guess would be that the video would have been followed soon after by an opportunity for people to pay money as an investment. Sorry. Scam. HiLo48 (talk) 01:57, 10 January 2012 (UTC)
- (editing convlict) Did you watch the video? Here it is again! --70.179.174.101 (talk) 01:25, 10 January 2012 (UTC)
- Yes I watched it. Very amusing. The TV news loves these things. They crop up about every six months. They're always either cons, or sadly self-delusional "inventors", but they're great fun.
- It's like in the olden days when everyone would get excited because some crackpot and/or swindling alchemist said he could turn lead into gold. It was never true, it couldn't possibly have been true. But every time a few suckers would go for it and everyone else would have a good laugh.
- That particular one is Genepax. They mysteriously ran out of money and closed in 2009. They never actually proved that their car worked the way they claimed. Probably they had built a primitive metal-hydride cell. Or maybe they just had batteries hidden under the seats. Who knows?
- I strongly suspect that they got a bunch of Venture Capitalists to fork over some cash before they suddenly shut down, but I can't find any evidence of that.
- They never proved that their car was running on water, apparently expecting us to take their word for it. Many people suspected that it was running on a home-made metal hydride battery, (which do have water in them, but it's not the water that gets "used up".) APL (talk) 06:09, 10 January 2012 (UTC)
- This looks like yet another conspiracy: Maybe Big Oil bought up their property and/or assets or paid off the owners to sell out their company. Perhaps the company ran out of money because the new owners made it that way, while the old owners enjoyed the windfall of new wealth. --70.179.174.101 (talk) 07:00, 10 January 2012 (UTC)
- Yea, I'm sure that's exactly it. These people claimed they could do something completely impossible. When it turns out they can't it must be because they're being oppressed, not because it was impossible all along.
- Seriously, free-energy con artists are a dime a dozen. (Many of them even get on TV, because the TV news stations love this junk even more than they love crackpot scientists who say something harmless is actually super dangerous, or vice-versa. TV News is mostly just entertainment. Don't take any of it too seriously.)
- P.S., Please don't edit my post. That's not how the ref-desk works. APL (talk) 09:37, 10 January 2012 (UTC)
- This looks like yet another conspiracy: Maybe Big Oil bought up their property and/or assets or paid off the owners to sell out their company. Perhaps the company ran out of money because the new owners made it that way, while the old owners enjoyed the windfall of new wealth. --70.179.174.101 (talk) 07:00, 10 January 2012 (UTC)
- Of course you CAN make a pizza out of rock, it's called transmutation. However it costs a lot of energy ;-) So I guess this points out an obvious hard issue, you need to get a positive energy gain from your fuel. And it has to be economically viable. And of course oil companies will continue as long as the money flow, even if that means death to everyone else. Electron9 (talk) 01:21, 10 January 2012 (UTC)
- Hey, why bother with a water-fueled car? I found a metric ton of YouTube videos about dilithium fusion, which is apparently much more efficient. --Mr.98 (talk) 03:06, 10 January 2012 (UTC)
- Patents are listed in the public domain. They cannot be made to disappear. Even if an oil company did buy the patent to this wondrous process, the identity of the patent and its purpose would still be available to the public. Why have we never been told the identity of the patent(s) purchased by the oil company? Dolphin (t) 06:31, 10 January 2012 (UTC)
- Presumably the evil oil conspirators (Since they're apparently uninterested in making a king's ransom selling unlimited zero-cost energy, and driving their competitors out of business.) would keep the water-engine as a trade secret. That's pretty ridiculous as well, though. Apple can't even keep their latest phones a secret, you're telling me nobody would leak plans or theoretical background to the water-engine? Not one Big Oil employee would publish the secret plans under their own name and win a Nobel prize? All those Genepax employees are all bought off so well that a billion dollar invention doesn't tempt them? The Pentagon couldn't keep a secret that big!
- All nonsense. We all know how corporate America works. Big Oil Corp would buy the patents, and sell the free energy devices for an unimaginable fortune. All their CEOs, and top executives would give themselves gigantic bonuses. If that cut into long-term profits they wouldn't give a crap! They'd write themselves a giant bonus check, cash out their shares, and give their investors the shaft! That's how corporations work nowadays. APL (talk) 09:51, 10 January 2012 (UTC)
- Patents are listed in the public domain. They cannot be made to disappear. Even if an oil company did buy the patent to this wondrous process, the identity of the patent and its purpose would still be available to the public. Why have we never been told the identity of the patent(s) purchased by the oil company? Dolphin (t) 06:31, 10 January 2012 (UTC)
- To summarize the water-fueled car article, a water-fueled car that turns water into hydrogen and oxygen (which is what the video claims) can't work because water has a lower potential energy than the corresponding quantity of free hydrogen + free oxygen. Burning hydrogen in an oxygen atmosphere releases energy, so it makes sense that to convert water to hydrogen and oxygen, energy must be added.
- It is possible, however, to make a car that runs on hydrogen by converting hydrogen and oxygen into water. However, producing hydrogen also takes energy, so in the end it might not be worth the necessary investment. This might change if extraction of hydrogen from Jupiter or another gas giant becomes feasible, but so far that's a long way off. --140.180.15.97 (talk) 21:04, 10 January 2012 (UTC)
- Personally I find "water fueled cars" disappointing, even for a conspiracy theory. I mean come on people, let's have a little creativity! Why not a car that is powered by neutrinos colliding with a certain nuclear isomer, or which uses "very high frequency sound" to wring energy out of vacuum fluctuation or vibrations in the P-brane. If we must consider a P-braned idea, might as well be a good one. ;) Wnt (talk) 19:08, 12 January 2012 (UTC)
Krakatoa explosion – must it happen again?
[edit]When Krakatoa exploded in 1883, it killed 40,000 people. From a recent TV doco, I learnt that the island is growing again very quickly (in geological terms) and will soon have the same volcanic form that caused the prior explosion. Next time, it will destroy probably 10 times the number of people that it did in 1883. This is confirmed in the WP article. There seems to be a: "It is as Allah wills" sort of fatalism here. Why do we have to wait for an "inevitable" catastrophe? Drop the big one, I say! Nuke the mother, and KEEP ON nuking it every time it raises its ugly head from beneath the waves! Why do we have all these nukes? Let's do something useful with them. That's my three pence worth anyway. What say you? Myles325a (talk) 01:43, 10 January 2012 (UTC)
- Two points. Firstly, I doubt that we know enough about volcanoes to know how to usefully bomb it, even it's possible. Secondly, Nuking has side effects. See Chernobyl. HiLo48 (talk) 02:02, 10 January 2012 (UTC)
- Two other points: Both a future eruption and Chernobyl would have far worse effects than nuking Krakatoa. Whoop whoop pull up Bitching Betty | Averted crashes 02:13, 10 January 2012 (UTC)
Op Myles325a back. How is it that Chernobyl "would have far worse effects than nuking Krakatoa. Chernobyl did not kill 40 000 people. Or is that because they are natives and thus not worth Russian lives.
- The Krakatoa eruption that destroyed the island involved an energy equivalent to about 200 megatons of TNT. That's four times larger than the largest nuclear bomb ever detonated, and about 170 times the energy of the largest nuclear bomb actively maintained in the current US arsenal. Even if we wanted to blow up the island up with nuclear bombs, it could take a lot of them. At the same time, if you do it poorly, there is a significant risk of triggering a large eruption. We don't really know how to blow up a volcano safely. Beyond that, people tend to take a very dim view of polluting the environment with radioactive fallout, which is likely if you used nuclear weapons to destroy a volcano. Maybe there is a way to vent the volcano before a catastrophic eruption, but I doubt anyone would seriously use nuclear weapons for this purpose. Dragons flight (talk) 02:15, 10 January 2012 (UTC)
OP myles325 back live. I ADVISE that very thing. If the use of them cannot be rationalised for this task, then it cannot be rationalised for ANY tasks, including military ones.
- We have to destroy the
villagevolcano in order to save it. Clarityfiend (talk) 03:01, 10 January 2012 (UTC)
- Prediction is very difficult for geologists. Extrapolation from the recent past (and within the last 10,000 years is considered "very recent" in deep time) doesn't tell you what will happen in the near future. The error bars are huge, and the understanding of the science itself is dynamic and changing. (Remember that plate tectonics, on which all current seismological theories are based, only became scientific consensus in the 1970s. This isn't to denigrate the current understanding, just to point out that the most recent paradigm shift is pretty recent indeed.) "Very quickly" in geological terms could be tens of thousands of years, so it's not clear that this is something that really needs much more than fatalism, unless you're deciding whether to live there, and even then, your chances of dying from some other cause greatly outstrip the chances of dying from Krakatoa. I'm not sure if anyone's done any really rigorous studies as to what would happen if a large nuclear explosion was detonated in a volcano, but I see no reason to assume a priori that it would be a positive thing. --Mr.98 (talk) 03:02, 10 January 2012 (UTC)
- Some references. Fehér Klára, A földrengések szigete (novel, 1968, Móra, Budapest) has something like this as the main plot point: the heros are digging a hole in a volcano to avoid eruption. This is played in an optimistic future, when volcanos are the last natural force to be ruled, in particular, weather is already controlled by humans. Jules Verne, The Mysterious Island has as a plot point a volcano eruption predicted successfully, though there's no consideration of averting the eruption. Antoine de Saint-Exupérym The Little Prince says that the volcanos on the Prince's asteroid burn with a steady flame and never erupt because the Prince sweeps them every day, but notes that this technique could not work on Earth because our volcanos are two large. What? This is not the Humanties desk you say? – b_jonas 05:59, 10 January 2012 (UTC)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/The_patient%27s_skin_is_burned_in_a_pattern_corresponding_to_the_dark_portions_of_a_kimono_-_NARA_-_519686.jpg/220px-The_patient%27s_skin_is_burned_in_a_pattern_corresponding_to_the_dark_portions_of_a_kimono_-_NARA_-_519686.jpg)
I have personally experienced volcanic ashfall on three separate occaisions.It's not fun. Neither is the distinct possibility of a volcano-generated tsunami, a pyroclastic flow burning your house down or a lahar burying the whole town in mud. When a nearby (as in, within like 150 miles since they can kill you from that far away) volcano is active, it tends to fill your thoughts at every idle moment. But it sure beats the hell out of being covered in keloids or feeling your teeth melt while they are still in your mouth, or watching your neighbor turn into a pillar of fire, or even having every single device that is dependent on any type of computer technology fail simultaneously. But sure, nuke the volcano, two disasters for the price of one! Beeblebrox (talk) 07:23, 10 January 2012 (UTC)
- This would be the Lex Luthor scheme from Superman: The Movie, and we know how well that turned out. ←Baseball Bugs What's up, Doc? carrots→ 11:21, 10 January 2012 (UTC)
I'm puzzled by the OP's "will soon have the same volcanic form that caused the prior explosion". Does this actually mean anything geologically? --ColinFine (talk) 13:02, 10 January 2012 (UTC)
- A reasonable guess is that he means the volcano will gradually build up to the kind of geologically volatile structure that resulted in the earlier eruption. ←Baseball Bugs What's up, Doc? carrots→ 13:59, 10 January 2012 (UTC)
- Krakatoa was 813 m high when it blew; Anak Krakatau is currently about 324 m and growing at 2 to 7 meters a year. So we have about a hundred years left. Rmhermen (talk) 15:25, 10 January 2012 (UTC)
- But is the shape or size of the surface feature actually of any great consequence? Surely it is what is going on deep below the surface that will govern when an eruption occurs? --ColinFine (talk) 00:38, 11 January 2012 (UTC)
- Krakatoa was 813 m high when it blew; Anak Krakatau is currently about 324 m and growing at 2 to 7 meters a year. So we have about a hundred years left. Rmhermen (talk) 15:25, 10 January 2012 (UTC)
- It sounds like your goal is use small nukes to periodically blow the plug off the volcano, so it can have many small eruptions, like in Hawaii, instead of occasional huge explosions. There's the issue of us not knowing what we're doing, and the pressure has likely already grown to where we could trigger a dangerous eruption. The radiation danger was mentioned, too. Perhaps by the time it does erupt on it's own, our prediction methods will be better and we can fully evacuate. Combining all these factors makes it better to wait. StuRat (talk) 21:07, 10 January 2012 (UTC)
- The problem is that we call what happens in Hawaii a "volcano" just as we call what happened at Krakatoa a "volcano", but the mechanism and type of event is so vastly different that it doesn't serve us well to think of them as all that similar. Hawaii is a shield volcano and Krakatoa is a stratovolcano. Catagorizing them together is like categorizing a Hurricane and a Tornado as the same thing because they both called storms and they both spin. --Jayron32 01:04, 11 January 2012 (UTC)
Asteroid impacts can also be used. By changing the orbit of an asteroid, it can be made to impact at any point on Earth. By aiming for Yellowstone National Park, the next eruption of the supervolcano can be triggered. An asteroid of about 1 km diameter is needed to penetrate the magma chamber. Count Iblis (talk) 22:44, 10 January 2012 (UTC)
Op myles325a back live. You'd want to be pretty accurate. You'd be really in deep do-do if you got it wrong by a fraction. Myles325a (talk) 03:46, 12 January 2012 (UTC)
Some points to answer concerns raised.
1. N Bombs create radioactivity.
Too right they do. HUNDREDS were exploded in open air in the '50s / 60s and NO ONE was affected. And some the highly diluted radioactive matter ended up in polar ice, where it provides excellent calibration when ice strata are examined. (Of course this backs up the evil-utionists but that's by the by).
Also, we would be aiming to put one of these muffies straight down its evil little cake hole, so far down it would have to put a toothbrush up its arse if it wanted to give it a brush. And that doesn't create a milliwatt of radiation. So let's go for it! NOW!!! Not manana....
2. We don't know much about bombing volcanoes.
Oh yeah, says who? We would know a lot more if we had some practice. How about starting on some smaller ones, using conventional explosives. Won't get nowhere sitting on our butts and having a siesta.
3.Krakatoa eruption = energy [of] 200 megatons of TNT = 4 times larger than largest nuclear bomb.
Hey, get your maths book out. The N Bomb used would not have to be equal to the power of the volcanic explosion; why would it? And even if it did, hey, 4 N bombs? Yanks gotta have that many. They don't? Well hey, they is begging the Ruskies for seats to "fly me to the moon", why not cadge some from them?
4.Nuking has side effects. See Chernobyl. HiLo48 (talk)
Gee whizz, you might be a macrame expert but not a nuclear one, LiLo48 (there are 48 of you?) Chernobyl was a "meltdown" not an explosion, and it was an accident, not a deliberate act. French tested God knows how many big bombs UNDERGROUND, and there was not a nanoserv of radiation, tho you would have thought the pinko demonstrators were dying from radiation burns they way they screamed their tits off about it.
5. Lex Luthor scheme from Superman" movie did not turn out well ←[[User:Baseball Bugs|Baseball Bugs]
Yeah, I think we should have flying cars coz they worked in Chitty Chitty Bang Bang, and we should avoid putting crustaceans near our faces coz of what happened in Alien. Grow up. This is Wikipedia, not Holy Gut Buster COMIX.
All in all, the objections raised above are typical lilly livered surrender monkey guff. America was the CAN DO! land, now it is full of manana...ites who can only dream up reasons they should do nothing at all cept sit on their butts, chewin' on a straw and smoking a roach. We shoulda done bombed the bastard way back straight after World War 2. Longer we wait, more nukes needed, and more danger. Nuke every couple of decades would be like keeping the lawn nice and neat and not letting it grow into a Goddam jungle. Of course some people don't give a damn about Pacific Islanders. If your sister was on one of those fatal shores, you'd be singing a different tune, by Gum. All those people God's children too, their lives just as valuable as those of the Yanks.
God done give everything to Man for a good reason. Reason for dinosaurs was coz they could breathe fire, being dragons, and thus dry out the environment and light camp fires when the whole world was saturated after the Flood. Reason we got the N Bomb was so we can blow up volcanoes and make canals like Panama in a day, not in 50 years! And what we do? Keep them in silos! Silos is for wheat brother, keep the N Bomb right down the gullets of the volcanoes, which is, in fact, the Devil's door to Earth. Myles325a (talk) 03:46, 12 January 2012 (UTC)
- You seem to have no idea how volcanoes work. You seem to imagine that all one has to do is stick a few nukes down its throat and you would be done. The pointy mountain is just the surface expression created by rising magma. The real deal is the magma chamber deep underground (9 km deep for Krakatoa) where molten rock pools and accumulates. Nuclear bombs at the surface can do nothing to cool the magma chamber. The best one can hope for is that by opening a vent to the surface you will trigger an eruption that is less severe than what would happen naturally if left alone. However, opening a large vent and releasing all of the stored energy at once is pretty much a recipe for a major eruption. Taking nuclear bombs and merely blowing up the mountain (which as noted would take many of the typical nukes) will do very little to stop or even delay a major eruption unless the magma chamber also discharges. And we haven't the faintest idea of how to do that safely. The best we might hope for is to trigger an eruption at a time of our choosing after moving people to safety. However, given that modern volcano warnings systems often give weeks or months to evacuate, I'm not sure accelerating an eruption with nukes will necessarily save lives. Also, detonating a bomb underground does nothing to mitigate radioactive fallout if the volcano then proceeds to force all of the radiative ash back up and out into the air. Volcanoes can create huge ash falls that blanket large regions. It isn't going to help anyone, if the falling ash is also radioactive. Dragons flight (talk) 05:26, 12 January 2012 (UTC)
Op myles deleted this, by accident I think, and his response follows a previous comment, so I'll stick this back here...
- I think we need to call in Xenu for technical assistance with those H-bombs. ;) The mechanics of volcanic eruption perplex me - I don't understand how releasing pressure increases pressure (if it does). Still, I am intrigued by the notion that someone could drill a fairly small hole into a volcano, surrounded by a heated casing (some kind of liquid metal circulated through the magma chamber to keep it warm?) and slowly draw off the magma in a controlled way, at the same rate that it enters the chamber, to avoid instability. I'd think the amount of electric power and steam for heating generated by such a plant would be enormous, and if it delays or stops the eruption, so much the better... Wnt (talk) 22:50, 10 January 2012 (UTC)
- Geothermal energy extraction is already operating at various places around the world, including the notably non-volcanic region (thankfully, as I live close by) of Southampton, England as well as other UK locations. Installing it on an active volcano would be difficult, because the engineering installations required would not easily cope with the relatively large and rapid shifts in the ground manifested in such places. Without actually crunching the numbers, my feeling is that the amounts of energy extractable by mankind's puny efforts would make negligable difference to the timing or magnitude of a pending eruption. {The poster formerly known as 87.81.230.195} 90.197.66.53 (talk) 02:00, 12 January 2012 (UTC)
OP myles325a back live. As [this WP account has it], the most probable reason for the extreme violence of the eruption is that it was an EXPLOSION, not JUST an eruption. If a vent had opened, then thousands of tons of cold sea water would have poured onto the hot magma, causing immediate and catastrophic pressure build-up. And steam was observed coming from the site for weeks before. And the other factor is that, of course, it was the sea-borne tsunamis which did most of the damage. If you negate the possibility of an enormous build-up of magma close by to sea water then you would have the more common and relatively harmless volcanic eruption. No massive explosion, and no tsunami. The catastrophe was NOT due to an earthquake. We have had volcanic eruptions galore. In modern times, they have caused minimal loss of life. You need an EXPLOSION, and one at SEA, the two necessary and sufficient conditions for a disaster. And what can you do to minimize the possibility of such a disaster? Nuke the muffy! Even if some radiation escaped, it would do little harm - think of all those above-ground tests in the 1950 – 60s. The idea is to make as many ventilation vents on the sea bed to allow the magma lots of places it can get out. Then it will not accumulate to vast reservoirs under enormous and dangerously high pressures. Simple as that. Myles325a (talk) 08:07, 12 January 2012 (UTC)
- Nuclear testing is believed to have caused tens of thousands of additional cancers in the US [1][2][3], and perhaps hundreds of thousands of deaths in China [4][5] where safety precautions were much lower. Dragons flight (talk) 09:55, 12 January 2012 (UTC)
- The other question to ask is whether a nuclear explosion really can do that much to a volcano. According to the formula underground nuclear testing a 64-megaton H-bomb should generate a cavity 2200 feet in radius, which is actually much more impressive than I'd thought, but is it enough to get magma to the surface from a chamber which could be miles down? Now admittedly if you can get the bomb into the magma chamber somehow you should surely be able to vaporize a lot more rock than if you set it off in solid ground, creating a tremendous amount of pressure, but getting it there is no easy feat, and if you could dig that tunnel, maybe you could just draw off the magma? By comparison, a coal-fired power plant takes in trains of 10,000 tons of coal (which contains more energy than TNT) at least daily, so it is indeed conceivable that over a year or more you can do more work to the ground by conventional means than with a nuke, and of course you can do that work in a way that seems carefully engineered rather than in a haphazard roughly spherical cavity. Wnt (talk) 19:01, 12 January 2012 (UTC)
ATP--used by all/most organisms?
[edit]Long time user, first time questioner on the ref desk. Today, I was checking out Adenosine triphosphate as a reader rather than as an editor...and I cannot for the life of me figure out if ATP is used by all biological organisms, most, or just a limited number. It may well be that the info is in the article somewhere, but I'm just not seeing it. I'm not looking for any sort of exact breakdown, more a general feel: is ATP universal, or is it one of a number of options? I imagine that once upon a time, many years ago, I learned this in college bio...but I'm getting too old to recall such things without electronic aid. Appreciate the help in advance. Qwyrxian (talk) 02:57, 10 January 2012 (UTC)
- Yes, ATP is used by all (known) living organisms. From Microbiology: An Introduction (Tortora et al., 1995, p. 129):
- "In aerobic respiration and anaerobic respiration, a series of electron carriers called an electron transport chain releases energy that is used . . . to synthesize ATP. Regardless of their energy sources, all organisms use similar oxidation-reduction reactions to transfer electrons and similar mechanisms to use the energy released to produce ATP." [6]
- Though ATP is used by all living organisms, it's not the only energy currency. GTP is another nucleoside triphosphate that fills the same type of role as ATP does in a number of biochemical pathways. (That's not to say that they are interchangeable—some reactions employ ATP, some GTP. TenOfAllTrades(talk) 03:26, 10 January 2012 (UTC)
- Thanks, that is exactly the info I was looking for. Qwyrxian (talk) 03:33, 10 January 2012 (UTC)
- So far as I know, all known life uses related proteins, specifically RNA polymerases, to create the mRNA transcripts which are used to direct the production of those polymerases and other proteins. And all those polymerases work by the same principle, of using NTPs, including ATP and GTP, to provide the energy for this polymerization reaction. Thus, without exception, ATP and GTP are used as energy storage methods by every organism with a genetic code, even viruses (though in that case they co-opt this energy from another organism). However, ribozymes can mediate the same reaction (at a slow rate) without the need for a protein, and, I think, in theory a different ribozyme could indeed mediate such a reaction without using an NTP for its energy source but some other nucleotide derivative instead. Such ribozymes are of interest to researchers as an analog for early living organisms; thus it is possible that some uncharacterized living organism is out there with this, or some other biochemistry. But this is about as close to a rule without exception as can be found in biology. Wnt (talk) 23:05, 10 January 2012 (UTC)
- Thanks, that is exactly the info I was looking for. Qwyrxian (talk) 03:33, 10 January 2012 (UTC)
amaloydosis
[edit]My Mom passed away in 1988 from Amaloydosis. Do I have a chance of getting this disease? I am a female of 56 years. E-mail [redacted email] — Preceding unsigned comment added by 198.228.199.175 (talk) 18:59, 10 January 2012 (UTC)
- There are many types of amyloidosis. Your risk of developing it will depend on what type your mother had, in addition to many other factors. This is something best asked of your doctor. 148.177.1.210 (talk) 19:03, 10 January 2012 (UTC)
- This is exactly the kind of medical advice Wikipedia can't give. If you want to ask which kinds of amyloidosis have a genetic basis, or how strong that is, we should try to answer, but we certainly can't give accurate information about her kind, whatever that might be, or your case in particular. Wnt (talk) 23:10, 10 January 2012 (UTC)
- The article says it's possible to inherit it or to acquire it. The simple (and largely useless) answer to the question, "Do I have a chance of getting this disease?", is YES. Just like you have a chance of getting most any disease (with the possible exception of prostate). And as noted above, "Talk to a doctor." ←Baseball Bugs What's up, Doc? carrots→ 23:39, 10 January 2012 (UTC)
To what extent are atoms understandable?
[edit]often when they teach us quantum mechanics, we are told not to try to visualize atoms, because they are unimaginable.Well, to what extent?When we study chemistry, for example, which discusses interactions that occur in a scale not much bigger than the atomic scale, or biochemistry, for example how DNA codes proteins, we see explanations that are... well very imaginable and sort of mechanical.And also, new methods of microscopy seem to give us images that at least show how atoms are arranged in space.So I wanna know, how unimaginable are atoms, and when some models fit very well experiments, is it safe to visualize atoms according to that models?--Irrational number (talk) 19:12, 10 January 2012 (UTC)
- Atoms are not unimaginable. But they are different than what students usually imagine them to be and that's why teachers often tell them to stop wasting time trying to imagine them. It's part of the "shut up and calculate" philosophy of teaching physics. Dauto (talk) 20:33, 10 January 2012 (UTC)
- I think that approach is a mistake. Most people think visually, so giving them a way to visualize things helps a lot. Just like a globe is a useful, but not entirely accurate, model of the Earth, so are atomic models. We just need to keep in mind where the model is off, like the Earth not having a metal rod thru the center. StuRat (talk) 20:47, 10 January 2012 (UTC)
- A globe is a much better representation of the Earth than any possible imagery is for an atom. A better example would be trying to imagine distances on the Earth if you're only allowed to view a Mercator projection map. There's a precise mathematical relationship between distances on the map and distances on the Earth, but it's hard to make that relationship intuitive if you've never seen a sphere in your life.
- The explanations in chemistry and biochemistry seem mechanical partly because they're highly simplified and wishy-washy. No analytical quantum mechanical solution is possible for anything more complex than hydrogen, so these simplifications are needed to get anything done. Also, biochemical molecules, especially proteins and DNA, are enormous by the standards of quantum mechanics. Many proteins are tens of kilodaltons, almost macroscopic compared to the one dalton hydrogen atom that quantum mechanics can describe. --140.180.15.97 (talk) 21:16, 10 January 2012 (UTC)
- well, my point is that they work, and they work pretty well in a lot of occasions, so why not think as if they really represent the "image" of atoms?--Irrational number (talk) 21:47, 10 January 2012 (UTC)
- The problem is that the models have a tendency to reinforce misconceptions that the teacher is trying to dispel, so naturally the teacher tells the students to stop thinking about those visual models. Dauto (talk) 22:55, 10 January 2012 (UTC)
- I agree with Irrational. All models, visual or otherwise, are an imperfect representation of the thing they model. They're still better than nothing. All models can lead to misconceptions, even precise mathematical models. Overemphasis of the canonical formalism in undergraduate QM seems to have left a lot of people with the impression that quantum mechanics is all about collapsing wave functions, for example.
- I think teachers emphasize the mathematics not for the benefit of the students, but because it's the only part they themselves understand. Most of them, anyway. I think Feynman would agree with the statement that atoms are little fuzzy balls. -- BenRG (talk) 03:37, 11 January 2012 (UTC)
- I want to mention instrumentalism, although I'm not sure whether to accuse you of veering towards it by saying "they work", or applaud you for resisting it by trying to imagine something. Card Zero (talk) 14:47, 11 January 2012 (UTC)
- by "they work" I mean that they explain natural world very well.--Irrational number (talk) 16:13, 11 January 2012 (UTC)
- I want to mention instrumentalism, although I'm not sure whether to accuse you of veering towards it by saying "they work", or applaud you for resisting it by trying to imagine something. Card Zero (talk) 14:47, 11 January 2012 (UTC)
Enrichment percent of Pu-239 ?
[edit]Regarding the latest international crisis, How high enrichment does Pu-239 need to have before becomes a weapons usable material?, guess Pu-241 falls into a similar category. Electron9 (talk) 19:25, 10 January 2012 (UTC)
- The article you linked to states that "weapons-grade" plutonium is at least 93% Pu-239 and has no more than 7% Pu-240. Whoop whoop pull up Bitching Betty | Averted crashes 19:47, 10 January 2012 (UTC)
- Is that separated from atoms with different proton number or from differen isotopes of Plutonium? Electron9 (talk) 19:51, 10 January 2012 (UTC)
- Those are isotopes. (Pu-239 tends to capture neutrons in a reactor and become isotope Pu-240 which is unsuitable for weapons.) RJFJR (talk) 20:53, 10 January 2012 (UTC)
- Is that separated from atoms with different proton number or from differen isotopes of Plutonium? Electron9 (talk) 19:51, 10 January 2012 (UTC)
- There are degrees of unsuitability. It's true that a government weapons program wants <7% Pu240, but more than that doesn't mean the bomb would be a dud. As the Pu article says, over exposure in a reactor makes too much Pu240, so military reactors (used to make weapons-grade Pu) fish their fuel out relatively early, while civilian power reactors keep it in and so cook up more Pu240. In John McPhee's The Curve of Binding Energy, Ted Taylor talks about how someone might steal civilian post-reactor fuel elements, do some challenging but not impossible chemical and metallurgical steps to separate the Plutonium from the bulk of the uranium-oxide and make either a plutonium oxide or plutonium metal pit from that. As he's not talking about isotopic separation of the Pu, that would have a relatively high proportion of Pu240 (too high to be called "weapons grade", but not, Taylor argues, for it to make a weapon unviable). As Pu240 has too high a spontaneous fission, any bomb someone might make would dismantle itself as it was being explosively assembled, and so would be very inefficient and dirty - but it would, Taylor claims, explode never the less. Taylor's thesis is that if someone can steal some post-reactor fuel, they can probably (perhaps over a period of time) steal quite a lot, thus making up somewhat for the inefficiency of their device. It's an old book (and perseverates on the security of civilian nuclear installations one hopes have long been improved) but it's scary nonetheless. -- Finlay McWalterჷTalk 21:26, 10 January 2012 (UTC)
- I don't think Taylor talks about stealing heavily irradiated spent fuel in that book; spent fuel is going to be too radioactive for your average terrorist or amateur. My recollection is he's talking about converting liquid plutonium oxide (I think), which is not suitable for a bomb,into a metallic form that would be useful for a weapon. This was in reference to the fact that many people at the time (early 1970s) thought that plutonium oxide was not a huge terrorist problem on account of it being difficult to work with, and were shipping it around rather cavalierly. (I think you're confusing the two things.) He was especially worried about the amount of plutonium you'd create through nuclear reprocessing. Reprocessing itself (removal of plutonium from spent fuel) is not something you can do in your basement; it requires pretty specialized facilities (hot cells) to do so without killing yourself immediately. --Mr.98 (talk) 21:42, 10 January 2012 (UTC)
- There are degrees of unsuitability. It's true that a government weapons program wants <7% Pu240, but more than that doesn't mean the bomb would be a dud. As the Pu article says, over exposure in a reactor makes too much Pu240, so military reactors (used to make weapons-grade Pu) fish their fuel out relatively early, while civilian power reactors keep it in and so cook up more Pu240. In John McPhee's The Curve of Binding Energy, Ted Taylor talks about how someone might steal civilian post-reactor fuel elements, do some challenging but not impossible chemical and metallurgical steps to separate the Plutonium from the bulk of the uranium-oxide and make either a plutonium oxide or plutonium metal pit from that. As he's not talking about isotopic separation of the Pu, that would have a relatively high proportion of Pu240 (too high to be called "weapons grade", but not, Taylor argues, for it to make a weapon unviable). As Pu240 has too high a spontaneous fission, any bomb someone might make would dismantle itself as it was being explosively assembled, and so would be very inefficient and dirty - but it would, Taylor claims, explode never the less. Taylor's thesis is that if someone can steal some post-reactor fuel, they can probably (perhaps over a period of time) steal quite a lot, thus making up somewhat for the inefficiency of their device. It's an old book (and perseverates on the security of civilian nuclear installations one hopes have long been improved) but it's scary nonetheless. -- Finlay McWalterჷTalk 21:26, 10 January 2012 (UTC)
- It's worth noting you don't enrich plutonium the way you do uranium. You just use different reactor cycles to make sure that the plutonium you make isn't too contaminated — you run a weapons reactor differently than a power reactor. (You could, in theory, enrich plutonium the same way you do uranium, but it would be very difficult, in part because of plutonium's increased radioactivity and toxicity, and it would be a stupid and wasteful way to do things. If you can enrich uranium, you should enrich uranium.) But as Finlay says, it's worth noting that there is evidence that reactor grade plutonium — relatively high levels of Pu240 — can be used in a bomb. In 1962, the Atomic Energy Commission did test a bomb fueled with "reactor-grade plutonium" and "it successfully produced a nuclear yield."[7] It's not an ideal material and it won't get your maximum bang for your buck, but if you're worried about terrorists (or even just large numbers of deaths from inefficient weapons!), it's still worth being concerned about. (Remember that even a fizzle of half a kiloton is still many, many times the size of the Oklahoma City bombing or 9/11 in its effects.) It is considered more proliferation-resistant than weapons-grade plutonium, and given the option, no nuclear weapons state would use it in their weapons if they could use weapons-grade Pu or HEU, but it's still weaponizable. --Mr.98 (talk) 21:42, 10 January 2012 (UTC)
- I was under the impression that a fizzle bomb is no more explosive than the high explosives used to implode the device? the only exception would be some fusion boosting, but then you got to get that reaction started too. Electron9 (talk) 00:16, 11 January 2012 (UTC)
- Fizzle (nuclear test): "... a nuclear bomb fails to meet its expected yield. ... For practical purposes, a fizzle can still have considerable explosive yield when compared to conventional weapons." -- ToE 04:17, 11 January 2012 (UTC)
- Fizzle can also mean that only a fraction of the potential energy is released. --Mr.98 (talk) 12:42, 11 January 2012 (UTC)
- Indeed it's worth remembering the 2006 North Korean nuclear test is generally considered a fizzle, with some low estimates of about 0.55 kT TNT equivalent. While there have been quite a few intentional and accidental explosions significantly larger then this (List of the largest artificial non-nuclear explosions#Conventional explosions for nuclear testing and the next section), the Father of All Bombs, which is probably currently the most powerful conventional weapon has a yield of at most 44 tons TNT equivalent. In other words the most powerful conventional weapon is a whole order of magnitude less powerful then the low estimate of the North Korea probable fizzle. Meanwhile the 2009 North Korean nuclear test may not have been a complete success either but appears to have been at least 3 kT TNT equivalent meaning it was probably larger then the Halifax Explosion and all but a few of the human made conventional explosions that have occured. Nil Einne (talk) 10:58, 12 January 2012 (UTC)
- The problem with Pu-240 is that it causes the bomb to go off too soon, before the plutonium has been fully compressed, which reduces the amount of nuclear fission that takes place and lowers the yield. --Carnildo (talk) 02:32, 13 January 2012 (UTC)
- Right, but even a low nuclear yield is still a big boom. We tend to lose sight of that fact when we're accustomed to talking about the big weapons of the Cold War or WWII, but when it comes to deterrence or terrorism, a boom is probably a boom, if you're only targeting cities (and not, say, hardened military installations). --Mr.98 (talk) 13:46, 13 January 2012 (UTC)