|MadSci Network: Astronomy|
Dear Shourya, This is a great question, but as far as we know, the universe is not expanding faster than the speed of light. According to Einstein’s Theory of Relativity, anything with mass has to travel at a speed less than that of light, and the only thing that can travel at the speed of light is radiation, like light or gravitational waves, or massless particles. This means that we can get light from early stars, although it will take a long time for the light to get to us if the stars are very far away. With that said, let me mention one situation when it is thought that the universe did seem to expand faster than light, but not in the way we usually think. The uniformity of the universe seems to indicate that in the early stages of expansion, the universe underwent a very rapid, very brief increase in size called “inflation.” This theory was put forward by the physicist Alan Guth. His idea is that the pressure of the vacuum actually caused the space between the matter to increase. This means that the matter did not travel faster than light, but by increasing the space in between the matter, the universe appeared to expand faster than light. Cosmic inflation is not occurring now, so the rest of the universe is moving at speeds less than light. Therefore, if we wait long enough, we should be able to get light from any other part of the universe. For some more information you might try looking at http://web.mit.edu/physics/facultyandstaff/faculty/alan_guth.html and http://en.wikipedia.org/wiki/Cosmic_inflation . Well, Shourya, I hope that answers your question. Please let us know if you would like any more information. Thank you for your interest. Sincerely, Jim Guinn Georgia Perimeter College
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