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I eventually found this article:-
http://www.smithsonianmag.com/smart-news/speed-light-can-vary-180953949/
What a rubbish article.
I eventually found this article:-
http://www.smithsonianmag.com/smart-news/speed-light-can-vary-180953949/
This does not change the fundamental value of the speed of light constant (c). The slowing is the delay caused by absorption and reemission of particles in the medium.
I neither said nor implied that it did. I simply pointed out to Mike that light DOES slow down based on medium.
if you'll look at the post directly above mine, you'll note he asked if a denser medium actually changes the speed of light.
Your questions all seem to ignore the fact that everything you measure is relative to your own frame of reference, or to some other frame of reference that you can observe conveniently.
If we take two cars that leave each other at 50 mph then 1 hour later they are 100 miles apart. However, if one car remains stationery and the other car departs at 100 mph then again the cars a 100 miles apart after 1 hour but it will be the car that accelerated to 100 mph that experiences the time change and increase in mass. At least I think that is how it works
If you have a passenger in a third car (Car T) moving at 50 MPH w.r.t. to car M, this person sees both Car M and Car S moving at 50 MPH away from him and sees corresponding changes in time and mass. (Miniscule for 50 MPH, but still there.)
Ain't relativity grand?
But it is Car M (its driver) that sees the greatest change in mass and time?
No. A Doc said, it is all about relative motion.
None of the drivers see any change in the mass of their own car.
When he arrives back at earth 24 hours of his time will have passed and the message sent from the planet at Alpha Centauri will have arrived 24 hours before he arrived.
Assuming instantaneous acceleration to speed c, yes. And your problem is?
I think that where you run into SERIOUS problems with this thought experiment is that by moving at an impossible speed you get an impossible result.
I don't see anything in the thought experiment inconsistent with Relativity.
Mike is actually struggling with the concept that it is the difference between the travellers' frame and the observers' frame that is the whole story with Relativity.
Asked in 1919 whether it was true that only three people in the world understood the theory of general relativity, [Arthur Stanley Eddington] allegedly replied: 'Who's the third?