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Name: Russel
Status: student
Grade: 9-12
Location: IA
Country: USA
Date: May 2, 2011


Question:
If Earth is now seeing light from early galaxies born 13 billion years ago, and we all came from the same Big Bang, how did Earth beat the speed of light to get to present location so quickly?


Replies:
Russel,

Unfortunately, because we do not, as yet, have the technology to replicate the energies and densities involved in a Big Bang, we can only extrapolate to what conditions must have existed in the very first tiny fraction of a second of the Big Bang. However, much of our math and data suggest that the Big Bang indeed resulted in the expansion of the universe - BUT what was expanding in that first fraction of a second, was not galaxies and planets, but rather subatomic particles and elementary particles. In effect, our theory states, that in that first fraction of a second, the universe grew exponentially and was filled with subatomic particles. Still within a tiny fraction of a second, these subatomic particles combined to form matter. A few minutes after the Big Bang lighter nuclei and years later electrons and nuclei started forming atoms. After a really long period of time, these atoms started forming larger masses (due to gravitational effects). So by the time stars, planets, galaxies formed, the universe is pretty much as large as it is now - the sudden expansion had slowed down really dramatically.

So when we say that we are only now beginning to see light from across the galaxy, it is because that light did indeed not start until the universe was already very much expanded.

Greg (Roberto Gregorius)


Dear Russel,

Good question.

Earth did not beat the speed of light. Galaxies 13 billion years old are easily visible from Earth using powerful telescopes, especially the Hubble. We do not, however, see all the way back to the moment of the Universe's birth, since that was too long ago.

Sincerely
David H. Levy


You have to be very careful when referring to time, distance, expansion of the Universe, the speed of light and related subjects. Things are very counter-intuitive. The "age" of the Universe is based upon Doppler shifts of radiation (light). The larger the shift the older and further apart are the source and "us". The "oldest" and "further apart" are the sources of the radiation -- microwave background. Now here you have to "hang up" your intuition. Unlike our classical intuition, it is not like there is some outside observer "watching" all of this going on. After the "Big Bang" space itself is being created. There is no outside observer looking at all this going on. Space itself is being created -- not like watching a train going by, but like the train itself is being created. Now that is pretty weird!! But that is necessary to understand the experimental data. The Earth is/was not in a race with some other object, because then you have to put down some outside marker to measure the motion of the Earth (actually the whole Milky Way galaxy) compared to some other object(s). But there are not any such outside observers, because then you have to compare the motion of our galaxy against this outside common reference. But there are not any such common references. So the Earth is not/was not in some sort of race with another galaxy/astronomical body.

We do not have any experience with the Earth comparable to actually creating space and time on the scale of the Universe. This all sounds complicated, because it is! The whole concept of actually "creating" space and time is a concept where we have no parallel experience in our experience.

Vince Calder



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