Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Jim Morris on 15/03/2011 18:03:27
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Jim Morris asked the Naked Scientists:
Hello!!
I've recently become an avid listener (http://www.thenakedscientists.com/HTML/podcasts/) to both The Naked Scientist and The Naked Astronomy podcasts (http://www.thenakedscientists.com/HTML/podcasts/). I find both very interesting and entertaining. Keep up the good work.
Here's my question: Since microwaves travel at the speed of light, how is it possible for the microwave background radiation to be "left over" from the Big Bang?
It seems that the microwaves would have traveled out in front of all of the matter in the universe as it expands. Did it "bounce" off of "something" or am I just missing an obvious point?
Thank you for your time
Jim Morris
Tampa, Florida USA
What do you think?
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Your answer to Jim in Tampa about the Cosmic Background Radiation was a bit incomplete. Something that I still have a hard time wrapping my mind around is that while nothing in the universe can move faster than light, the universe itself can and does expand faster than light. So, since the places from which the CBR that we now see emanated are currently moving away from us faster than the light itself, we can view the light. The other result of this fact is that while the CBR won't "run out" per se, there will come a time that all part of the universe from which CBR might reach us are all moving away from us faster than the light is moving, so we _will_ stop seeing it (contrary to what was said on the show).
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The ''universe'' in nothing more than the set of objects that interact between temselves. If we see the distance of a far away object increasing with time faster than the velocity of light, and as all velocity, save that of light, is relative to the velocities of other objects, what does it mean that the -set- of objects interacting has a velocity in the saparation of these objects?