Tag Info

New answers tagged

0

Cosmological redshift can be interpreted as the accumulated Doppler redshifts between infinitely many frames of reference, each locally at rest and moving away from us at a certain velocity. So you cannot distinguish the two because they are basically different cases of the same thing. However, as it says in @Rob Jeffries' answer above: when looking at ...


1

I think there are duplicates of this, but couldn't immediately locate them. The answer is you cannot tell observationally whether a single redshift measurement is caused by the expansion of the universe or by something moving away rapidly. However, if one wished to interpret the ensemble of redshifts that we see in a non-expanding universe, then you must ...


0

There are no the transverse Doppler effect in your two cases. Because there is always a classical Doppler shift when the distance between the source and the observer changes with time. See: Investigations on the Theory of the Transverse Doppler effect blog.sciencenet.cn/blog-267101-748804.html 2013-12-11.


2

If the source is moving faster than the speed of sound then ahead of the source it produces a shock wave instead of a sound wave. This is the infamous sonic boom associated with faster than sound flight. Your equation is giving you a silly result because no propagating sound wave exists, so there is no frequency to be calculated. If you're interested in ...


0

It is an evidence for the expansion, as seen in supernova studies. Read this paper http://adsabs.harvard.edu/abs/2008ApJ...682..724B We present multiepoch spectra of 13 high-redshift Type Ia supernovae (SNe Ia) drawn from the literature, the ESSENCE and SNLS projects, and our own separate dedicated program on the ESO Very Large Telescope. We use ...


1

You would experience no redshift, ignoring gravity and the expansion of space.



Top 50 recent answers are included