If it [the universe] was expanding fairly slowly, the force of gravity would cause it eventually to stop expanding and then to start contracting. However, if it was expanding at more than a certain critical rate, gravity would never be strong enough to stop it, and the universe would continue to expand forever.
I think the human race doesn't have a future if we don't go into space. We need to expand our horizons beyond planet earth if we are to have a long-term future. We cannot remain looking inward at ourselves on a small and increasingly polluted and overcrowded planet. We need to look outward to the wider universe.
Think of our dna. In the last million years, our dna hasn't changed at all. It's really much the same as it was in the jungle, a million, two millions years ago. But in the last 200 years, our destructive capacities have increased many, many millions of times over. Why don't we see intelligent signals from outer space? Because in all likelihood, once the civilization reaches the point our civilization has reached, it destroys itself.