Big Bang Questions: How Far, How Long, Possible?

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Discussion Overview

The discussion revolves around the duration and distance of the Big Bang event, particularly focusing on the inflationary period and the implications of space expanding faster than the speed of light. Participants explore theoretical aspects and interpretations of cosmological models.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions how long the Big Bang lasted and how far objects could have traveled in that time, suggesting that some things may have traveled many light years in a fraction of a second.
  • Another participant mentions that the early universe expanded significantly, doubling in size about 80 times in a very short time frame, specifically during the inflationary period.
  • A different participant clarifies that the expansion refers to space itself stretching, using the analogy of a rubber sheet, and notes that light still travels at the speed of light during this expansion.
  • One participant elaborates on the inflationary theory, suggesting it involves rapid expansion with estimates of doubling times and the challenges it addresses in standard Big Bang cosmology.
  • Concerns are raised about the possibility of space expanding faster than light, with a participant noting that relativity prohibits objects from moving through space faster than light but does not restrict the expansion of space itself.
  • There is mention of ongoing debates regarding the evidence for inflation, with some participants expressing confidence in its validity while acknowledging that further tests are needed to confirm it.

Areas of Agreement / Disagreement

Participants express varying degrees of certainty regarding the inflationary model, with some supporting it based on existing evidence while others highlight the need for additional tests, indicating that multiple competing views remain.

Contextual Notes

Participants reference specific time scales and theoretical constructs related to the inflationary period, but there are unresolved questions about the exact duration and mechanisms involved in the Big Bang and inflation.

guitarphysics
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How long did the big bang last (initially)? How far did everything travel in that time? I was under the impression that it all happened in a fraction of a second and some things went many light years. If I'm right, how is that possible? (Traveling faster than the speed of light). If I'm wrong, what actually happened? Thanks
 
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Well, the early universe doubled in size about 80 times before settling down in the boring old radiation/matter/expansion version we now observe. And, all that happened in only a few ticks on the Planck clock
 
And when Chronos says "doubled in size about 80 times..." he means that space itself expanded by this amount. Imagine a rubber sheet that starts stretching at the time of the big bang and continues to stretch today -- this is expansion. Light still travels at c during expansion.
 
guitarphysics said:
How long did the big bang last (initially)? How far did everything travel in that time? I was under the impression that it all happened in a fraction of a second and some things went many light years. If I'm right, how is that possible? (Traveling faster than the speed of light). If I'm wrong, what actually happened? Thanks

I think its right to say the "big bang" refers to a theory that the universe expanded from a very hot dense state. That expansion is estimated to have began about 13.7 bio years ago. But of course is still going now, it has never stopped since that period.

I think what is being discussed here is the inflationary period. This is the theory that the unvierse went through a period of very rapid expansion. Nobody knows how long it lasted, but if my memory serves me correctly (feel free to correct me if I have it wrong) but somehting like a doubling every 10^-37 seconds and at leats something like 60 doubling times. This number is estimated from the amount of doubling which are reuiqred to solve some difficult problems found in the standartd (without inflation ) big bang comsology.
Read here:
http://en.wikipedia.org/wiki/Inflation_(cosmology[/URL])

To answer the question how could space have moved faster than light? Reltavity forbids obejcts to pass each other through space faster than light. But it has no restriction on how fast sapce can expand.
Did inflation happen ? there is good evidecen that it did but we are still waitiing for one more key test, read here:
[url]http://www.nature.com/news/2009/090415/full/458820a.html[/url]

I think until that test (read the article) is done there is still room for doubt, but at the moment I think most astronomers would put their money on inflation being right as it has passed many tests so far.
 
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