Wikipedia:Reference desk/Archives/Science/2019 July 20

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July 20[edit]

How fast are we moving through space?[edit]

Is it possible to accurately measure how fast we are moving at any one time?

the earth spins the earth orbits the sun is the sun moving? the galaxy spins and moves? and on and on.

do we require reference points to calculate movement? — Preceding unsigned comment added by (talk) 13:29, 20 July 2019 (UTC)

It is possible to compare velocity using the Cosmic microwave background#CMBR dipole anisotropy. 368 km/s. Graeme Bartlett (talk) 13:42, 20 July 2019 (UTC)
In any one (duration-less) instant of time, Zeno's arrow is neither moving to where it is, nor to where it is not. Since everything is motionless at every instant, and time is entirely composed of instants, motion is impossible. DroneB (talk) 15:17, 20 July 2019 (UTC)
If you wonder what DroneB means, see Chronon. I think the OP was intending to ask the question in a Newtonian model of reality. Dbfirs 17:30, 20 July 2019 (UTC)
We DO require reference points (or, rather, reference frame) to calculate movement. Once a reference frame is chosen you can calculate movement pretty accurately Gem fr (talk) 15:52, 20 July 2019 (UTC)
On the grand scale of things, the earth's motion around the center of the galaxy is going to be pretty much in sync with the sun's orbit around the center of the galaxy. Just a smidgen of retrograde motion by the earth and the other planets relative to the sun, if you were at the center of the galaxy and could see the solar system. ←Baseball Bugs What's up, Doc? carrots→ 16:23, 20 July 2019 (UTC)
An interesting Q is, if there are multiple big bangs, could we tell if our "universe" is moving with respect to the others ? Since the cosmic background radiation is left over from our big bang, it won't do. Is there any more universal frame of reference ? SinisterLefty (talk) 17:38, 20 July 2019 (UTC)
The very definition of a Universe means that, if there is something greater than our "our universe", then the universe is the greater thing, not the part you currently call "our universe". Comics' definition of "multiverse" with people moving between is just nonsense. Gem fr (talk) 19:19, 20 July 2019 (UTC)
Technically true, but I don't think that's a particularly useful argument. "Universe" and "Galaxy" were once thought to be synonymous, until it was discovered that there were other galaxies. And we didn't redefine "atom" when we discovered that they weren't actually undividable. If it was discovered that there were multiple big bangs resulting in multiples of what we currently think constitutes the universe, then we will have to either continue defining "universe" by its etymology and come up with a new word for "what is formed in a big bang", or redefine "universe" to mean "the type of thing formed in a big bang" and come up with another word to refer to all the universes and the "space" they reside within. Iapetus (talk) 08:22, 22 July 2019 (UTC)
Hence the term "science fiction". ←Baseball Bugs What's up, Doc? carrots→ 20:22, 20 July 2019 (UTC)
But a multiverse consisting of many, or perhaps infinite, universes is a valid scientific theory. SinisterLefty (talk) 21:05, 20 July 2019 (UTC)
It's a hypothesis, lacking any evidence. ←Baseball Bugs What's up, Doc? carrots→ 21:52, 20 July 2019 (UTC)
Yes, and so much so that it stops being scientific: there is no experimental findings that would prove or disprove such hypothesis Gem fr (talk) 06:28, 21 July 2019 (UTC)
That's true of many theories in physics, such as string theory. There were also many earlier such theories, like the existence of the Higgs boson and black holes, that took many years to verify (48 years and perhaps centuries, respectively). SinisterLefty (talk) 06:41, 21 July 2019 (UTC)
What test would you recommend for detection of a parallel universe? ←Baseball Bugs What's up, Doc? carrots→ 16:09, 21 July 2019 (UTC)
If another universe expands into ours, then we will eventually find out about it, but it could be billions of years, or trillions, etc. Other than that, I have no idea. Also, the simplest solution is an infinite number of universes with all possible physical laws. This explains why the physical laws in ours support the evolution of life (those with incompatible laws never have anyone there to wonder about it). If there is only one universe, then you would need to explain why the physical laws just happen to be right for life to evolve, as the probability of that happening at random is extremely low.
What test would you suggest for string theory ? If you have none, does that make string theory science fiction ? SinisterLefty (talk) 16:32, 21 July 2019 (UTC)
It might be, but at least it's trying to explain observed facts. What facts have ever been observed to suggest a parallel universe? ←Baseball Bugs What's up, Doc? carrots→ 21:08, 21 July 2019 (UTC)
I already said that the observed physical laws are oddly "just right" to permit life. For example, if there was an even amount of matter and anti-matter, they would annihilate each other and destroy everything. So we end up in a universe with a difficult to explain lack of anti-matter. SinisterLefty (talk) 00:12, 22 July 2019 (UTC)
"Oddly just right"? Who says? ←Baseball Bugs What's up, Doc? carrots→ 02:30, 22 July 2019 (UTC)
Max Tegmark, for one: "Going from our universe to the Level I multiverse eliminates the need to specify initial conditions, upgrading to Level II eliminates the need to specify physical constants, and the Level IV multiverse eliminates the need to specify anything at all... A common feature of all four multiverse levels is that the simplest and arguably most elegant theory involves parallel universes by default. To deny the existence of those universes, one needs to complicate the theory by adding experimentally unsupported processes and ad hoc postulates: finite space, wave function collapse and ontological asymmetry." SinisterLefty (talk) 07:01, 22 July 2019 (UTC)
That premise sounds suspiciously like creationism. ←Baseball Bugs What's up, Doc? carrots→ 07:48, 22 July 2019 (UTC)
Indeed, this is just sophisticated metaphysics. Metaphysics is OK, but should never be mistaken for physics. Gem fr (talk) 07:59, 22 July 2019 (UTC)
He's a physicist at MIT, not a wack job. And there are many others who agree with him. And the lack of anti-matter in the universe is one of the unexplained problems in physics, as under the Big Bang theory they should have formed as equal and opposite pairs initially: [1]. SinisterLefty (talk) 14:17, 22 July 2019 (UTC)
(The one does not preclude the other!) If inventing parallel universes is needed to explain the assumptions, then the assumptions might be wrong. As my old math teacher said, "If you start with incorrect assumptions, you're liable to get 'interesting' results." ←Baseball Bugs What's up, Doc? carrots→ 15:04, 22 July 2019 (UTC)
You appear to assume that if the math leads to parallel universe, then the math must be wrong, because that's too weird. You seem to object to parallel universes because it's non-intuitive, but physics has led us to know that intuition is totally wrong outside our normal experience. Quantum mechanics and wave particle duality are two of many examples. And double-slit experiments show that something really bizarre is going on, in that electrons or other particles, fired one at a time towards the double slits, nonetheless form an interference pattern, despite having no other particles to interfere with. Another physicist, David Deutsch, has suggested the many-worlds interpretation where each particle in our universe is interfering with a version of itself, in a parallel universe, but which goes through the other slit. If the competing theories can be disproven, then this would strengthen the parallel universes interpretation. SinisterLefty (talk) 01:12, 24 July 2019 (UTC)
Your example of matter/anti-matter is very bad. Reality is no good at perfectly balancing things, so, what would strange is that they be in perfectly equal quantity for ever. You don't need an explanation for inequality, you would need one for their being perfectly balanced. Gem fr (talk) 07:59, 22 July 2019 (UTC)
String theory is not science. It may qualify as math (which is OK) or science-fiction (which is NOT OK) depending on whether you claim things could be so, or you claim they are really are so. Very different from the theories predicting Higgs boson or black holes, which took time to be confronted to observational facts, but could be. Gem fr (talk) 07:42, 22 July 2019 (UTC)
Forbes has a pretty great answer - at least to a nonscientist; I got a bit lost at the end there. 1700 km/hr rotation at the equator. 30 km/s around the Sun. 200–220 km/s around the galactic centre. Add galactic movement and the article came up with 627 ± 22 km/s relative to the comic microwave background. Great pics too. (talk) 17:49, 20 July 2019 (UTC)
Reference. Gråbergs Gråa Sång (talk) 17:56, 20 July 2019 (UTC)
The numbers cited in the Forbes article are the same as those in the article which Graeme Bartlett linked to above. As I understand it, the relevant number (i.e. of Earth relative to the CMB) is 368 ± 2 km/s; 627 ± 22 km/s is for the local group as a whole, but being anthropic we don't care about that, do we? HenryFlower 21:06, 20 July 2019 (UTC)
I think we do. But we may differ, it doesn't matter much. Gem fr (talk) 21:54, 20 July 2019 (UTC)

FWIW - Excellent Question - Answer: "Nearly Two Million Miles Per Hour" => I've tried to answer (or, respond to) this question several times over the years - some of my efforts were published (FaceBook and The New York Times) - and are copied below if interested - hope this helps in some way - in any case - Enjoy! :) Drbogdan (talk) 22:09, 20 July 2019 (UTC)

The velocities should, of course, be added as vectors, not as scalars, though there may be times when they are all in approximately the same direction? Dbfirs 17:47, 21 July 2019 (UTC)
@Dbfirs: yes - agreed - adding velocities as vectors may be better - in which case, "nearly 2 M mph" may be an upper limit, I would think - also - the overall trajectory may at first seem to be linear over time to some - but may actually be a bit non-linear - due to the different directions of motion (including a combination of linear and/or circular/orbital directions) - perhaps in some helical (corkscrew?) fashion - in any case - Enjoy! :) Drbogdan (talk) 19:28, 21 July 2019 (UTC)
Well, the actual answer (as given in Graeme's link at the beginning of the discussion) is 368 km/s, which if I'm right is 822,960 mph. So, yes, within your upper limit. :) HenryFlower 11:40, 22 July 2019 (UTC)
@Henry Flower: Thank you for your comments - and calculation - yes, seems the velocity of the Earth speeding through the Universe (toward Andromeda Galaxy?) may be nearly 1 M mph (and perhaps no more than 2 M mph) - current estimated velocity range may be between 0.8–1.9 million miles per hour (1.3–3.1 million kilometres per hour) I would think - quite a ride (while sitting still?) on spaceship planet Earth no matter what velocity is chosen within the estimated range - in any regards - Thanks again for your comments and calculation - and - Enjoy! :) Drbogdan (talk) 13:34, 22 July 2019 (UTC)

How Fast Are We Moving Through Space? => "Nearly Two Million Miles Per Hour" [NOTE: Perhaps "Nearly One Million Miles Per Hour" may be better - see comments above]
(ie, 1.892 x 106 mph = 0.066 x 106/orbit sun + 0.043 x 106/sun + 0.483 x 106/orbit galaxy + 1.300 x 106/galaxy )
July 20, 2019

ASP: How Fast Are You Moving When You Are Sitting Still? = NASA = NASA (BEST?)
The Astronomical Society of the Pacific is an international nonprofit scientific and educational organization founded in 1889 ...
No. 71 - Spring 2007
How Fast Are You Moving When You Are Sitting Still?
By Andrew Fraknoi
Foothill College & the Astronomical Society of the Pacific
Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112.


My Related Published FaceBook Comments are copied below if interested --

Dr. Dennis Bogdan
November 6, 2009

MIND-BOGGLING? We've *All* Come A Long, Long Way From Where We Were When We Were First Born! - In Fact, Each Year, "Spaceship" Planet Earth Travels Nearly 20 Billion Miles Through The Universe! - Actually, We're All Hurtling Towards Andromeda Galaxy At Nearly Two Million Miles An Hour ( )! Kind Of Mind-Boggling - At Least To Some Perhaps! :)



My Related Published NYT Comments are copied below if interested --

Dr. Dennis and Joanne Bogdan
Pittsburgh, PA
November 12, 2014

Thank you for an Excellent article - Yes - a spacecraft landing on an astronomical object, Comet 67P, going 84,000 miles an hour ( ), is quite an accomplishment - however - for perspective - seems that airplanes routinely land on an astronomical object, spaceship planet Earth, going much, much faster - nearly 2 million miles an hour according to astronomers => - in any case - Thanks again for the Excellent article - and - Enjoy! :)

Dr. Dennis Bogdan

1 Recommend

C.Blacksmith commented Spain November 13, 2014

Speed is not an absolute measure. Planet Earth has a relative speed of 0 for airplanes (referring to its original position, the runway).
84,000 miles an hour is the relative speed of Comet_67P refering to Rosetta's original position.
Three big diferences:
- the acceleration process (which lasts 10 years)
- the distance (rendezvousing with the comet required travelling a cumulative distance of over 6.4 billion kilometres.)
- The automation (It will take the radio signals from the transmitter on Rosetta 28 minutes and 20 seconds to reach Earth, and the same to return to rosetta)

2 Recommend

Dr. Dennis and Joanne Bogdan commented Pittsburgh, PA November 14, 2014
Yes - I *Entirely* Agree - Thank You *Very Much* For Clarifying - Landing On The Comet Is A Truly Great Technical Accomplishment Of Course - Enjoy! :)


Hello. I came across this term while modifiying Morphosis (disambiguation), and found that the article's lead sentence is unintelligible due to false syntax. However, I couldn't figure out how to appropriately fix it – without having the cited sources at hand. Can anybody perhaps help out? Regards--Hildeoc (talk) 19:56, 20 July 2019 (UTC)

It might be simpler to start from scratch with a (cited) definition from someplace like here: heteromorphosis. (n.d.) Farlex Partner Medical Dictionary. (2012). Retrieved July 20 2019 from (talk) 21:38, 20 July 2019 (UTC)
I edited according to my understanding. Is that better? If not, feel free to edit yourself. Gem fr (talk) 21:50, 20 July 2019 (UTC)
@Gem fr: Thank you once again for fixing that! Best wishes--Hildeoc (talk) 08:15, 23 July 2019 (UTC)