Timeline for John, in his spaceship traveling at relativistic speed, is crossing the Milky Way in 500 years. How many supernovae explosions would he experience?
Current License: CC BY-SA 4.0
23 events
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| Jun 24 at 21:48 | comment | added | foolishmuse | @EricSmith I'm laughing at the first set of experiments - on the speed of light. All you have to do is put a mirror on Mercury and bounce a laser off it and back to earth. Lets say it takes 10 minutes. Now drill a tunnel though Venus, and bounce the laser through the tunnel, off of Mercury and back again. It suddenly takes 10 minutes +1 second. Time dilation from the gravitational field around Venus (i.e. general relativity) has changed the speed of light. So every single argument about the speed of light being constant obviously does not take GR into account. The same is true for SR. | |
| Jun 24 at 21:32 | comment | added | Eric Smith | en.m.wikipedia.org/wiki/Modern_searches_for_Lorentz_violation is a good place for you to look for experiments. So far all experiments show the Lorentz transform is the correct way to convert between reference frames. The principle of relativity itself is based on over 400 years of experiment dating back to Galileo. The onus is on those who believe in absolute speed to provide evidence. | |
| Jun 24 at 18:11 | comment | added | foolishmuse | @EricSmith as I have asked several times in these forums, show me a single example of this being true. A single example where the fast moving twin sees the stationary twin as younger. Or don't even show me an actual experiment, but simply design an experiment where this is true. People have some idea that time dilation is magic. But it's not. it's a physical reaction to movement in SpaceTime. | |
| Jun 24 at 18:06 | comment | added | Eric Smith | @foolishmuse take a closer look at Einstein's paper. The "gravitational field" he uses to explain the twin paradox arises only in one reference frame and lasts only while that twin is accelerating. Einstein very much accepted the principle of relativity and agreed that (except while accelerating) each twin would regard the other as aging slower. | |
| Jun 23 at 22:29 | comment | added | WillO | For the record, the upvote on the above comment is from me and was purely accidental. | |
| Jun 20 at 13:16 | comment | added | foolishmuse | @WillO your point would be correct if every criminal had to pass through a zoo in order to commit the crime. Every object must move through the gravitational field to move it all. That is why the gravitational field is important, as Einstein himself recognized. | |
| Jun 20 at 1:40 | comment | added | WillO | Let's just take a moment to digest what @foolishmuse is arguing: The gravitational field is everywhere, and therefore you can't explain the twin paradox without it. Just as, for example, there are zoos in every major city, so it would be impossible to explain urban crime without mentioning zoos. | |
| Jun 19 at 21:01 | comment | added | Arthur | @foolishmuse "Just the empty field in itself is sufficient" also known as SR. | |
| Jun 19 at 20:30 | comment | added | foolishmuse | @Arthur fortunately Einstein wasn't wrong on this point and his paper resolves the twin paradox completely without the need to do mathematical backflips. Yes, I do tend to work in our universe. But the same answer would hold in any other universe. It does not require a strong gravitational pull, just the empty field in itself is sufficient. I'll leave you with that. Have a good day. | |
| Jun 19 at 20:03 | comment | added | Arthur | @foolishmuse That's if you want to do the twin paradox in our universe. But the twin paradox doesn't make any reference to other stars, galaxies, or planets. It's just the two twins. And the paradoxical observations must be possible to resolve in a universe where those two twins are the only thing that exists. And don't come here and tell me that we have to take the gravitational field of the twins into account also. We do not. Besides, Einstein was human too, he was wrong on occation. And ultimately it doesn't matter. Yes, there is gravity everywhere, but its effects can still be negligible. | |
| Jun 19 at 19:55 | comment | added | foolishmuse | @Arthur Take a look at the paper I referenced. Einstein said that the gravitational field is everywhere. "All the stars in the universe can be thought of as taking part in the generation of a gravitational field". It can't simply be ignored. | |
| Jun 19 at 19:52 | comment | added | Arthur | @foolishmuse What gravitational field? Two twins, out in open space, one drives away in their rocket, then turns around and comes back, while the other stays inertial. There is no need whatsoever for there to be an Earth where the trip starts. | |
| Jun 19 at 19:36 | comment | added | foolishmuse | @Arthur As per the article I referenced, Einstein himself recognized that the gravitational field must be taken into account with these problems. | |
| Jun 19 at 19:32 | comment | added | Arthur | The only thing that separates GR from SR is the existence of gravity and spacetime curvature. SR itself is entirely capable of handling accelrations (although if you artificially and unneccessarily limit yourself to inertial frames of reference and Lorenz transformations, this isn't as clear). The standard twin paradox setup is completely absent any gravitionally relevant bodies, thus it is an SR phenomenon, and can be completely explained using only SR. | |
| Jun 19 at 13:11 | comment | added | foolishmuse | @in the twin paradox problem, there is always one twin who is moving fast, and one twin who is moving slow. In general it is accepted that the fast twin ages less than the slow twin. But of course the problem with the twin paradox is that from his frame of reference he can say that he is stationary and thus it is the slow twin who should be aging less. This is the whole paradox. I am looking for a single example where that has happened. Where the fast twin determines that the slow twin has aged less. Is that intell enough for you? | |
| Jun 19 at 6:46 | comment | added | WillO | If I thought there were any chance of getting an intelligible answer, I would ask what "fast twin" and "slow twin" mean. | |
| Jun 18 at 22:05 | review | Low quality answers | |||
| Jun 19 at 18:57 | |||||
| Jun 18 at 18:54 | comment | added | foolishmuse | @naturallyInconsistent please point me to that experimental proof where the fast twin sees the slow twin as younger. I'd like to see it. | |
| Jun 18 at 18:19 | comment | added | naturallyInconsistent | The paper you are referencing is so early on that Einstein did not yet know that his GR is actually in direct contradiction, i.e. disagreement, with Mach's principle, that he was trying to invoke. You are just wrong, albeit misled by Einstein. In any case, we have experimental proof that, taking into account GR and all, the experimental twin paradox agrees with predictions. You could have just learnt about them. | |
| Jun 18 at 18:01 | comment | added | foolishmuse | @naturallyInconsistent if you read the referenced paper, Einstein was referring specifically to relative velocity and the twin paradox. So no, there is not a purely SR answer to the paradox issue. And until someone shows me a test in which the fast twin discovers that the slow twin is younger, I'll take Einstein at his word on this. There is simply too much evidence that he was right. | |
| Jun 18 at 17:58 | comment | added | naturallyInconsistent | I totally agree with you that, we sometimes do have to keep in mind that SR is only a limit of GR, and if the GR corrections are important, we cannot just assume that SR alone is sufficient. However, this question is asked purely for constant relative velocity, and so there must be a valid answer purely in terms of SR that GR will also agree upon. That is why you are getting my downvote. | |
| Jun 18 at 17:41 | history | edited | foolishmuse | CC BY-SA 4.0 |
added 93 characters in body
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| Jun 18 at 17:36 | history | answered | foolishmuse | CC BY-SA 4.0 |