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# Big Bang vs Speed of Light

Asked Dec 9, 2011, 03:25 AM — 6 Answers
I am 65 without any formal knowledge in physics or astrophysics but am fascinated by the subject. There is one thing that puzzles my and I cannot get it out of my head. In The Big Bang the universe went from zero to full size in a fraction of a second yet the laws of physics state that nothing travels faster than light. My logic tells me that the universe could only have expanded to 186,000 miles in the 1st second. Can you tell me if I have got it right?
Kind regards
Chris Ryan

6 Answers
 joypulv Posts: 15,732, Reputation: 11321 Uber Member #2 Dec 9, 2011, 03:58 AM
Supposedly the expansion of the universe is not constrained by the speed limit of light, which is defined by objects moving relative to each other. I don't understand expansion very well either, but since the arguments are ongoing among physicists, that's OK.
 ebaines Posts: 10,589, Reputation: 5794 Expert #3 Dec 9, 2011, 08:08 AM
kingkit: the universe did not go to "full size" in a fraction of a second. In that first second it expanded from zero to about 186,000 miles in radius, as you suggest. Think of a grenade exploding - the shrapnel expands away from the center at essentially a constant speed. So too with the universe. And it's still expanding. The radius of our universe is essentially 186,000 miles per second times the age of the universe (about 13.8 billion years) which works out to mean the furthest objects we could ever see are 13.8 billiion light years away. And every year that distance grows by another light year.
 TUT317 Posts: 657, Reputation: 395 Senior Member #4 Dec 9, 2011, 01:40 PM
Quote:
 Originally Posted by ebaines kingkit: the universe did not go to "full size" in a fraction of a second. In that first second it expanded from zero to about 186,000 miles in radius, as you suggest. Think of a grenade exploding - the shrapnel expands away from the center at essentially a constant speed. So too with the universe. And it's still expanding. The radius of our universe is essentially 186,000 miles per second times the age of the universe (about 13.8 billion years) which works out to mean the furthest objects we could ever see are 13.8 billiion light years away. And every year that distance grows by another light year.

Hi ebaines,

Perhaps kingkit is thinking of the inflationary period of the Big Bang.

Tut
 rupertpupkin123 Posts: 7, Reputation: 10 Junior Member #5 Dec 18, 2011, 05:55 AM
Like someone already said, it did not immediately go to full size. It expanded extremely fast though. In the matter of a few seconds it was already mind blowingly large. I saw a documentary on this once.
 rbawjaws Posts: 6, Reputation: 10 New Member #6 Aug 10, 2013, 06:25 PM
Answer with a question it has been found recently that the universe is not expanding at a uniform rate but is actually accelerating so where does that put your 1860000mles per sec expansion
 Tuttyd Posts: 50, Reputation: 20 Junior Member #7 Aug 11, 2013, 09:42 PM
Quote:
 Originally Posted by rbawjaws answer with a question it has been found recently that the universe is not expanding at a uniform rate but is actually accelerating so where does that put your 1860000mles per sec expansion
Yes, I believe it was an Australian physicist Brian Schmidt who proved that the universe is accelerating and an ever increasing rate. In fact it seems as though it is expanding faster than the speed of light.

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