Have we traveled faster than light?

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Offline thedoc

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Have we traveled faster than light?
« on: 20/07/2012 01:30:01 »
Edwin Jury  asked the Naked Scientists:
Good day, Chris.
Your weekly programme on Cape talk / Radio 702 is my weekly treat, with complex issues reduced to comprehensible explanations. It delights me no end when clear language is used as compared to the expert language which so many people are only able to use - such as my doctor and friend in IT.
This morning I was perplexed by an article on the Guardian UK website, about Japanese scientists having discovered the oldest galaxy, using telescopes on Hawaii.
The gist of the article is that the Big Bang was some 13,7 billion years ago. The Japanese team have discovered a galaxy 12,1 billion light years away. Apparently this is effectively looking back in time.
Here is my problem, as a lay person.  If the Big Bang was 13,7 billion years ago and the light form this distant galaxy took 12,1 billion years to reach us on the edge of the Milky Way, the difference is 1,6 billion light years.  On the face of it, our matter / energy took only 1,6 billion light years to get to this point in space.
What have I got wrong, as this surely cannot be? It implies matter moving at faster than the speed of light.
Yours truly,

Edwin Jury
Porterville, Western Cape.

What do you think?
« Last Edit: 20/07/2012 01:30:01 by _system »


Offline evan_au

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Re: Have we traveled faster than light?
« Reply #1 on: 20/07/2012 13:03:28 »
The concept of the Big Bang is that our galaxy has taken around 13.7 billion years to get where it is now. This journey has taken place at less than the speed of light [apart from a theoretical period of "inflation" immediately after the Big Bang, which lasted much less than a microsecond].

This newly discovered galaxy took 1,6 billion years to get to where it was when our astronomers saw it. The light for that picture took 12,1 billion years to reach the telescope, traveling at the speed of light.

12,1 + 1,6 =13,7  without requiring anything to go faster than light.