Photon's travel through space who's metric is growing. Those paradoxes are resolved by understanding what I wrote above - each galaxy is more or less "at rest" in its neighborhood, and so no superluminal motions are ever involved. At high redshifts, that interpretation leads to apparent paradoxes, or contradictions with special relativity. The cosmological redshift can be _interpreted_ as a relative speed, provided you're in the low-redshift limit. I found the Wikipedia article on "Hubble's Law" to be a good, quantitative explanation of the issues. Rather, it is a "cosmological redshift", which is induced in the light during transit, by the global stretching of space (specifically, by the scale factor a(t) of the cosmological metric). The redshift we observe from far distant galaxies is NOT a "Doppler shift" - it is NOT due to some intrinsic motion of the source relative to us. The galaxy is not moving _in the rest frame of it's local neighborhood_: that is, whatever motion the galaxy might have, relative to "local observers" is small (of order a few hundred km/s). SR doesn't set any limits on how much that stretching might be.īy Michael Kelsey (not verified) on Sorry, it sounds like I was too telegraphic in what I wrote. When we look out and see a highly redshifted galaxy, that doesn't mean the galaxy is actually _moving_ rather, the light from that galaxy has gotten stretched along with the space between us, while the light was in transit. The cosmological expansion involves space itself "stretching," and the various galaxies are just going along for the ride. Not very fast, and certainly not fast enough for SR to complain :-) For example, seen from Andromeda or the Magellanic Clouds, the Milky way is moving at something like 100 km/s or so. In any event, each one of those galaxies is (nearly) at rest with respect to nearby observers. With the expansion of space, widely separated galaxy may or may not be causally connected. Special relativity applies to objects which are in motion with respect to a nearby (causally connected) observer. Sinisa's two links (see #18) are the right place to go to address your confusions. I know, I know there’s still the issue of that pesky cosmic microwave background radiation … but hey! No theory is perfect.īy Lou Jones (not verified) on Don, Rhonda et al. Personally I hope the Steady State Theory makes a comeback. To give the conclusions serious consideration. When you meld physics and the film industry you have I don’t believe we can blithely ignore a proposition that is built around scientific rigor and the circular plot of a movie. So I give Bondi, Hoyle, and Gold a nod, they developed an attractive theory, a comfortable theory. Infinity allows for a Deity with a role to play, some design work new stars, new planets, intelligent life omnipotent creations that harmonize the celestial order. It takes the big cosmic pyrotechnics out of the picture, my fevered brain relaxes, it’s receptive to clearer concepts. A universe that has existed forever is something I can deal with. But Steady State is a different hypothesis. I don’t believe we mortals were blessed with the mental apparatus to grasp such a thing. The thought that a universe could be packed into a levitating subatomic mote. It violates some scientific principle, I think. Anyway, I could never whipsaw my mind around the notion of a Big Bang, the making of something from nothing. Whenever we look to the heavens we will see the same thing. It givesĪssurance that the universe will maintain a consistent look, Worked out between matter, gravity, and recession. No Big Bang, just an ongoing series of littleīangs, necessary to populate the space between galaxiesĪs they pull away from one another. Is pretty much discredited now, too bad because I like
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