The universe is expanding. We know that much. But we don’t know why, since the gravitational force of all these galaxies should be pulling things together. Albert Einstein used what he considered to be a cheat: the cosmological constant, which was a fancy way of Einstein saying “the universe is in equilibrium, but I don’t quite buy how or why.”
From the Chandra Observatory site. A decent picture of what we *think* the energy distribution of the universe may look like.
Well, time passes and the engine of discovery continues to fire. A nobel prize was recently awarded to a few proud eggheads who think they’ve discovered dark energy.
The concept of dark energy emerged in 1999 as a way to explain the fact that the expansion of the universe, once thought to be slowing ever since the big bang about 13.7 billion years ago, was accelerating. That resurrected the idea of a cosmological constant, introduced by Einstein more than 80 years ago as a “fudge factor” to explain why the universe then appeared to be in equilibrium, rather than being pulled together by gravity.
A few years later, however, astronomer Edwin Hubble discovered that the universe was not in stasis, after all, but was expanding. There was no “constant.” Einstein condemned his own idea as “my greatest blunder.”
But in the 1990s, astronomers found ways to use supernovae as cosmic “standard candles” whose luminosity could be analyzed to track the history of the universe’s expansion as far back as 9.8 billion light-years.
That led to the 1999 discovery that the expansion of the universe was accelerating rather than slowing. There had to be some “repulsive force” overcoming the gravity that should have been causing the universe to come together.
Astronomers called the force dark energy, and “it mimics the cosmological constant,” said Michigan Technological University astronomer Robert J. Nemiroff. Einstein may have been right after all.
(The Washington Post, January 12, 2006)
I can’t do this subject a lick of justice, so watch this video:
Einstein may have been right all along. Pretty cool stuff. It’s just like science to get our hopes up, dash them, get them up again, dash them again, and then get our hopes up again. The process may seem annoying, but I find it to be a hell of a ride.
Now, let’s sit back and wait for the 42,000 revisions of this observation over the next 500 years. Science!
