Hi, I was looking through past exams for one of my courses, and I came across a question I wasn't quite sure how to do, so I was wondering if anyone could give some hints (or possibly the rationale for solution), thanks!(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

Observers in three universes A, B, and C measure identical constants. However, universe A is a critical universe (i.e.p=pc (with c being critical density), Universe B is an accelerating universe, and Universe C is close to being an empty universe (i.e. p<<pc or p~0). Rank the ages of the three universes as measured by these observers from largest to smallest, and explain your reasoning.

2. Relevant equations

None really...

3. The attempt at a solution

I'm not quite sure what you can infer about the age of A if it's a critical universe, because it always stays flat with p = pc. C is probably the oldest universe, since it's emptying out, and I'd guess B is younger than C, since it's accelerating so not yet emptied out.

However, I was also wondering what the relevance of the identical Hubble constants would give in this problem.

Thanks for anyone who can give some help / hints!

edit - maybe this should be in advanced physics forum?

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# Homework Help: Hubble's law and expansion question

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