Dark Energy to Erase Big Bang's Fading Signal

Irene Klotz, Discovery News

When astronomers in the distant future cast their eyes around the cosmos, they will come to the conclusion that our galaxy is alone in the universe.

Even with the most sensitive detectors, future scientists will not be able to observe the leftover radiation from the Big Bang explosion, study the motion of distant galaxies to conclude that space is expanding or even see distant objects.

In the future, the force astronomers now known as dark energy, will stretch the universe beyond detection, with objects receding faster than the speed of light.

"Nothing can move through space faster than the speed of light, but space can do whatever the hell it wants as far as we know," Arizona State University cosmologist Lawrence Krauss said last week at the American Association for the Advancement of Science meeting in Chicago.

Even without dark energy, there are regions of space moving away from us faster than the speed of light, Krauss added.

"When that happens, they carry objects with them, like a surfer on a wave. The light from those objects cannot reach us. So, eventually the universe will disappear before our eyes," Krauss said.

Scientists have some time to figure it out. Based on the currently understood estimates of inflation, the new dark ages won't occur for another 50 billion years or so. The sun would have long since died, likely taking Earth along with it, but civilizations could be living elsewhere in the galaxy.

"It's perfectly reasonable to expect that there will be civilizations not that different than our own that could arise, but they will live in an empty, dark universe," Krauss said.

Scientists are on a quest for what may be the smoking gun for this inflationary view of the universe -- gravitational waves, which might have been imprinted as polarity in the background radiation left over by the Big Bang explosion.

"I think we'll know in 10 years time whether we can detect gravitational waves," said Massachusetts Institute of Technology's Alan Guth.

In April, the European Space Agency plans to launch its Planck telescope which will study cosmic background radiation. Physicists also may get some clues from experiments conducted in the world's biggest and most powerful particle accelerator, the Large Hadron Collider, which will be used to produce subatomic particles that may represent conditions in the extreme, high-energy environment of space.

"We live at a very interesting time, namely the only time in which we can empirically verify that we live in a very interesting time," Krauss said.