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Q & A: Expansion rate of the universe

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Most recent answer: 08/30/2013
Someone told me that if the speed of the expansion of the universe had been greater/lesser by one quintillion that the universe would have either dissipated or collapsed back in on itself. Is this true and is there a source I can go to for this information, and what would that speed difference be when calculated, also what effect or roll would dark matter have or play in this. Thank You, David.
- David (age 49)
Rotan Tx United States

Hello David

I think your friend is not right on this point.    In fact the expansion rate is changing  as we speak.  It has been measured and the evidence shows that it is actually increasing.   See:

As for dark matter, it is an important component of the universe.   Even more bizarre is the idea of dark energy. Take a look at


Maybe they meant some other parameter conected to the expansion. Some things do have to be very closely tuned (say the shape of the potential giving the early inflation,  ) in order to get a livable universe out. /mw

(published on 08/30/2013)

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