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**1. Homework Statement**

Observers in three universes A, B, and C measure identical constants. However, universe A is a critical universe (i.e.

*p*=

*p*c (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. Homework 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?