Somebody said this to me

[Phil]

The idea of it collapsing again is absurd, what would cause that?

If it were going to, gravity would cause it to contract but there will not be a big crunch.

At the centre of most galaxies are supermassive black holes which are slowly but surely consuming their parent galaxies.

If one extrapolates forward far enough(to a time when all suns have finally petered out) then it is easy to foresee that eventually the universe will consist of nothing but these blackholes and gravity.

And when they finally(after trillions of years)coalesce into one vast singularity which will contain the entire material universe, what then?

Are you asking what happens when all the black holes merge? If so, if that happens to black holes that haven't evaporated through Hawking Radiation, they will evaporate through Hawking Radiation. By the way, this isn't even on the scale of trillion cubed years.

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Zen,

There isn't much of a question that all matter eventually will find itself in black holes but why would two black holes (using this as an example) that are widely separated by say 1035 light years in a three dimensional space necessarily meet one another before the length of time it takes Hawking Radiation to evaporate them? Look at it this way, you have two atoms of Hydrogen in an otherwise "perfect" vacuum. How easy do you think it is for them to miss one another in a three dimensional container? I'll let you work out the math but the probability of them meeting is somewhere in a container say 10 light years on a side is so phenomenally large for all intents and purposes you can say it will never happen.