Lightyears and age

[AndersHermansson]

If the light reaching us from a distant galaxy is said to has been travelling for 12 billion years, then it is said to be 12 billion light years away. Did someone forget to consider the fact that the galaxy has been moving away from us in the meantime? The distance must be at least the double.

[Mentat]

Originally posted by AndersHermansson
If the light reaching us from a distant galaxy is said to has been travelling for 12 billion years, then it is said to be 12 billion light years away. Did someone forget to consider the fact that the galaxy has been moving away from us in the meantime? The distance must be at least the double.

That's why they always say that we are only seeing things as they were 12 billion years ago.

[neutroncount]

Originally posted by Mentat
That's why they always say that we are only seeing things as they were 12 billion years ago.

What Mentat said. We are seeing what the conditions are like THEN! A lot probably has changed if we were to see things locally.

[kleinma]

if i got you right... you are probably asking the same type of question i did... i got some good explanations.. here is the link

http://www.physicsforums.com/showthread.php?s=&threadid=2622