Something called phantom energy is as yet unproven to exist but if it does then the universe will eventually accelerate its expansion and even atoms will be pulled apart.

"Until now we thought the Universe would either re-collapse to a big crunch or expand forever to a state of infinite dilution," says Robert Caldwell of Dartmouth College, New Hampshire. "Now we've come up with a third possibility - the 'big rip'."

Its slated for 22 billion years from now so we can relax for now.

The question Caldwell and his colleagues posed is, what would happen if the rate of acceleration increased?

Their answer is that the eventual, phenomenal pace would overwhelm the normal, trusted effects of gravity right down to the local level. Even the nuclear forces that bind things in the subatomic world will cease to be effective.

We have more pressing problems that need to be solved first. For instance, in a mere 1 billion years increased light output from the Sun will make Earth too hot for human life. Therefore, we will need to move Earth. Some may already be living on Mars and will welcome the increased sunlight. But Mars is smaller and will be too crowded to hold everyone.

Of course by then the human race may either be wiped out by nanogoo or by robots.