Ever since the discovery of a mysterious property of the universe called "dark energy" scientists have feared that the fabric of the universe was, in time, going to rip apart, but Lawrence Krauss, a physicist at the University of Arizona, allays our fears in this story.
Dark energy is very weird stuff. For the first 5 to 7 billion years after the Big Bang the universe expanded at ever-decreasing rates as gravity acted as a brake on the exploding sphere of space-time, but then about 7 billion years ago the expansion began to accelerate, as if someone pushed the gas pedal all the way to the floor.
It turns out that the universe acts like a rubber band in reverse. As a rubber band is stretched the elasticity decreases and acts as a drag on further stretching. The "elasticity" of the universe, however, actually increases the more it stretches.
Imagine the universe as an inflating balloon with everything that we can observe resting on the surface of the balloon. The balloon is inflating faster and faster and although it doesn't appear that it will burst as it was originally feared, it does appear that the expansion rate will continue to accelerate until everything on the universe's surface is speeding away from everything else at close to or even more than the speed of light.
This, by the way, is why theories of an oscillating universe are no longer accepted. Once the universe expands to a certain point, it cannot collapse and thus cannot oscillate.
This means that eventually, billions of years from now, earth-bound observers would be able to see no other objects in the sky because they'd all be moving away at speeds so fast that the light from them would never reach us. Since the sun is one of those objects from which we would receive no light then, of course, there'd actually no longer be any earth-bound observers.
At any rate, here's the most fascinating thing about this. Scientists have determined that the amount of dark energy present in the universe cannot vary from the actual value by more than one part in 10(120). That's a one with 120 zeroes after it. If it did deviate from its actual value by more than this amount life would not be able to exist in the universe that would result. That is an unimaginably precise setting. It's the equivalent of the mass of a billionth of a trillionth of a trillionth of the mass of a single electron.
What an amazing thing that this dark energy is calibrated to just the right value to allow life to survive. What an extraordinary amount of blind faith it takes to think that it's just a lucky accident.RLC