Very, very slowly, the dwarf remnants of what was once our mighty sun will cool and dim, until it embarks on its final metamorphosis, gradually solidifying into a crystal of extraordinary rigidity. Eventually it will fade out completely, merging quietly into the blackness of space.

Many billions of years will elapse before the smallest, youngest stars complete their nuclear burning and shrink into white dwarfs. But with slow, agonizing finality perpetual night will surely fall.

Although gravity is by far the weakest force of nature, its insidious and cumulative action serves to determine the ultimate fate not only of individual astronomical objects but of the entire cosmos. The same remorseless attraction that crushes a star operates on a much grander scale on the universe as a whole.

The secret of our success on planet Earth is space. Lots of it. Our solar system is a tiny island of activity in an ocean of emptiness.

A universe that came from nothing in the big bang will disappear into nothing at the big crunch. Its glorious few zillion years of existence not even a memory.