MadSci Network: Astronomy

Re: how can we expect to see the first light?

Date: Fri Feb 2 08:11:01 2007
Posted By: Jim Guinn, Staff, Science, Georgia Perimeter College
Area of science: Astronomy
ID: 1168783691.As

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 

and .

Well, Shourya, I hope that answers your question.  Please let us know if 
you would like any more information.

Thank you for your interest.


Jim Guinn
Georgia Perimeter College

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