Why I am soooooo sorry that we are apparently (meaning according to the latest astronomical data and relativistic cosmologies) no longer in a closed (re-collapsing) universe. According to the latest, the expansion of the universe is decelerating, but at an ever lower deceleration which will cumulatively not be enough to turn the expansion around.
How terribly sad! Suppose that there were to have been enough
mass density in the universe to cause
the universe to stop expanding and then to contract. Then there are
theorems in GR which state that within a finite time everything will
recollapse to a final singularity.
Now, listen closely: We would
then already be INSIDE the event horizon of the final singularity. Yes, you, me, the earth the sun the solar system the galaxy the local cluster the supercluster etc. You
don't notice anything different do you? No "the earth shook" nor
Being inside the event horizon of a sufficiently large,
isolated Black Hole would feel exactly the same.
"But if I was inside the event horizon of a Black Hole wouldn't I be able to see the Black Hole I was falling towards!?"
Nope! A Black Hole, like any final singularity, is like next Monday. You can't see "next Monday" can you?