March 29, 2009


Does Dark Energy Really Exist?: Or does Earth occupy a very unusual place in the universe? (Timothy Clifton and Pedro G. Ferreira, March 23, 2009, Scientific American Magazine)

In science, the grandest revolutions are often triggered by the smallest discrepancies. In the 16th century, based on what struck many of his contemporaries as the esoteric minutiae of celestial motions, Copernicus suggested that Earth was not, in fact, at the center of the universe. In our own era, another revolution began to unfold 11 years ago with the discovery of the accelerating universe. A tiny deviation in the brightness of exploding stars led astronomers to conclude that they had no idea what 70 percent of the cosmos consists of. All they could tell was that space is filled with a substance unlike any other one that pushes along the expansion of the universe rather than holding it back. This substance became known as dark energy.

It is now over a decade later, and the existence of dark energy is still so puzzling that some cosmologists are revisiting the fundamental postulates that led them to deduce its existence in the first place. One of these is the product of that earlier revolution: the Copernican principle, that Earth is not in a central or otherwise special position in the universe. If we discard this basic principle, a surprisingly different picture of what could account for the observations emerges.

Most of us are very familiar with the idea that our planet is nothing more than a tiny speck orbiting a typical star, somewhere near the edge of an otherwise unnoteworthy galaxy. In the midst of a universe populated by billions of galaxies that stretch out to our cosmic horizon, we are led to believe that there is nothing special or unique about our location. But what is the evidence for this cosmic humility? And how would we be able to tell if we were in a special place? Astronomers typically gloss over these questions, assuming our own typicality sufficiently obvious to warrant no further discussion. To entertain the notion that we may, in fact, have a special location in the universe is, for many, unthinkable. Nevertheless, that is exactly what some small groups of physicists around the world have recently been considering.

The poor Rationalists go flitting, hither and yon, wherever the latest bright idea takes them, when all along they could have stayed right in the same place.

If you wonder how thoroughly the Copernicans/darwinists have been routed in the culture wars, we went to the Museum of Science in Boston today and saw an IMax film called greatest places. It ended by saying that Earth has incredible diversity of life, maybe the greatest diversity of any planet, in fact, may itself be the greatest place in the Universe.

Posted by Orrin Judd at March 29, 2009 9:05 PM
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