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Q & A: looking back

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Most recent answer: 10/22/2007
Q:
I understand that it takes billions of years for light to reach us from the observable "edge" of the universe (just for the sake of example, 15 billion years), but letís say youíre at that edge and looking back toward Earth--would you be looking back in time 15 billion years or into the future 15 billion years, i.e., how can you be looking back in time from both points of view?
- Richard Stuart (age 47)
Post Falls, ID
A:
There really isn't any edge. Anyway, sure you can look back either way. The light had to leave its source in the past to get where it's going later. imagine you were trading letters with a pen-pal, either way, the latest letter gives somewhat old news. Of course, the cosmic case isn't quite so simple, due to effects of general Relativity, but this basic part of the argument still holds.

Mike W.
Lee H


(published on 10/22/2007)

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