Shouldn't Light from Early Universe be Gone?

[clancy99]

Apologies if this has been asked already...

It is commonly said that the more powerful our telescopes, the further back in time we can see. My question is: Wouldn't there be a dramatic limitation on how far back we can see as a result of the light having already reached us when the universe was "smaller?" By way of illustration, assume the point in space we are observing is Point A, which is 15 billion light-years away. This, of course, means that we see Point A as it existed 15 billion years ago.

But, here's my conceptual problem. 15 billion years ago, the universe was much smaller. So wouldn't that 15 billion year-old light have been emitted from Point A when Point A was much closer than 15 billion light-years to the area in space the Earth presently occupies? And, if that's the case, wouldn't the light have already passed by the Earth and been absorbed by matter or dissipated or whatever? I understand space is expanding very rapidly, but my understanding is that it isn't THAT rapidly.

I don't know if 15 billion years is the limit...if there is such a limit...I just use that as an example.

[George]

You might want to use, say, 10 billion years ago since the age appears to be 13.7 billion years for the age of our universe. But, your question is still the same.

Light that is just now reaching us after it departed 10 billion years ago from Point A has traveled 10 billion light years distance in order to reach us just now, at least from our point of view. Even though at the time it left Point A it was much, much closer to us, it still had to travel through the space that was expanding between us and it, which would have amounted to 10 billion light years. Of course, Point A is "now" much further away, which we could discover if only we could instantly travel from place to place.

[Spaceman Spiff]

Read this link (http://www.astro.ucla.edu/%7Ewright/photons_outrun.html) carefully...

[stktos]

Spaceman Spiff, that is a very interesting link. thank you.
Never really thought of that before.
A few years ago, in a physics class we were going over radio waves. In the book It told of a large radio scope that was able to detect the background radiation still left from the big bang. Thought it was neet.