Comment Most insightful comment ever (Score 1) 848
Subject says it all! Thanks Hairyfeet :-)
You can observe things like the color of distant stars, the rotations of galaxies, even the cosmic background radiation. We can see, for example, that hot hydrogen on a distant star has exactly the same kind of spectroscopic signature that hydrogen here on earth does.
But we don't, we see a redshifted version. We have explained that this is because the galaxy is moving away but maybe it's something else.
P.S. I am a physicist, an experimental type.
"No matter where you go, there you are..." -- Buckaroo Banzai