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I had that same question once and also posted to usenet, and here's what I remember: * special relativity constrains local speeds: you can never see any massive body whizzing by faster than the speed of light, c. * this does not contradict the fact that some distant galaxies are moving away from us faster than c, something that is predicted by some cosmological models in general relativity. The space in between expands. * light's speed is equal to c locally, which means if a photon whizzes by, everybody will measure its speed to be c. * this does not contradict the fact that a photon emitted by a galaxy which moves away from us faster than c can eventually reach us. Locally it will always travel with speed c, the space between the galaxy and us expands, so the photon is exactly in the situation of the "ant-on-a-stretched-rubber-band" that I described above. Now, it depends on the particular cosmological model; in some models, some photons shot in our direction will never reach us. In the cosmological models that are currently en vogue, for every galaxy, there is a time when we will see it, we just have to wait long enough. The observable universe constantly enlarges and captures more and more galaxies as we speak. Note that this does not mean that there will be a time when we can see all galaxies at once. Here are the Google links: http://groups.google.com/groups?hl=en&threadm=xzqoh1dtok9.fsf%40uni-paderborn.de&rnum=19 and http://groups.google.com/groups?hl=en&threadm=AXEL.98Jan20204156%40euler.uni-paderborn.de&rnum=17 --AxelBoldt |
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