Universe Expansion or Contraction

The universe is expanding

The universe is expanding today, and it has done so since it was born in the Big Bang 12-15 thousand million years ago. The question is whether the expansion will go on forever, or if it will start to contract once in the far future. The answer depends on the total mass in the universe, a matter that we still don't know.

A dark death?

If the expansion is going on forever, all the stars will finally die, and everything will cool down. Everything left is a dark empty cold universe with no basis for life existing in it!

Or a red hot final?

If the expansion of the universe is reversed before it has been too cold, human can still live in it for a long time. But it will slowly start to become warmer and warmer as the contraction goes on. After a long time, it will become so hot that life again is impossible. In the end the whole universe have contracted totally into itself! What will happen then? Hard to answer!

Anyway, this is not our main concern today

So the question is whether we will freeze or we will burn. But this problem we have to solve later. There are other problems coming before that. First we must handle the possibility that the Earth may be hit by a huge meteoroid. This can mean evacuating from the Earth. Secondly we definitely need to learn how to evacuate the Sun system when the Sun is growing too big. (A few million years staying on March may be a temporary solution until the Sun will be too hot for that planet too.) After that is the time coming to deal with the universe expanding/contraction challenge.