So I was watching the segment "Into the Universe with Stephen Hawking" that came after the two "Curiosity" programs tonight on the Discovery channel. Normally I avoid that station for anything with actual scientific content as it's generally popularized and dumbed-down. Just the fact that they have to, after every commercial break, summarize everything they just spent the last 10 minutes talking about (as if the audience might forget during the commercials!) ruins it for me.
One of the statements they made in the show was regarding the state of the universe right after the big bang. Specifically they stated that about 100 seconds after the Big Bang the universe had expanded to an area roughly the size of our solar system from a single point.
However that stuck me as extremely odd. Our solar system is large enough that light takes many minutes to traverse it. So how did the universe travel faster than light?
For argument's sake say the orbit of Pluto is the edge of the solar system (the actual "edge" could be farther out, but let's use this measurement just to get going). Pluto's orbit is about 5,913,520,000 km from the sun. Now the speed of light is 29979.2458 kilometers per second. That means that light would take 197253.795 seconds to traverse the solar system's radius, a hell of alot longer than the boundaries of the universe actually spent moving that distance.
So I was under the impression that nothing can move faster than the speed of light. But apparently the boundaries of the universe did right after the Big Bang? Sure, I recognize that, at least according to this program, the universe has no "medium" outside it to expand in. So maybe the boundaries of the universe don't follow that law. But within the boundaries of the universe? Looks like space was expanding faster-than-light. Perhaps all of the content of the universe didn't move that fast and it's spent the last 14 billion years moving to catch up and fill the void. But something still doesn't seem right here.
Maybe someone who knows more about this stuff can fill me in?
One of the statements they made in the show was regarding the state of the universe right after the big bang. Specifically they stated that about 100 seconds after the Big Bang the universe had expanded to an area roughly the size of our solar system from a single point.
However that stuck me as extremely odd. Our solar system is large enough that light takes many minutes to traverse it. So how did the universe travel faster than light?
For argument's sake say the orbit of Pluto is the edge of the solar system (the actual "edge" could be farther out, but let's use this measurement just to get going). Pluto's orbit is about 5,913,520,000 km from the sun. Now the speed of light is 29979.2458 kilometers per second. That means that light would take 197253.795 seconds to traverse the solar system's radius, a hell of alot longer than the boundaries of the universe actually spent moving that distance.
So I was under the impression that nothing can move faster than the speed of light. But apparently the boundaries of the universe did right after the Big Bang? Sure, I recognize that, at least according to this program, the universe has no "medium" outside it to expand in. So maybe the boundaries of the universe don't follow that law. But within the boundaries of the universe? Looks like space was expanding faster-than-light. Perhaps all of the content of the universe didn't move that fast and it's spent the last 14 billion years moving to catch up and fill the void. But something still doesn't seem right here.
Maybe someone who knows more about this stuff can fill me in?
Last edited by JdeFalconr (2011-08-07 22:06:14)
