Friday, September 3, 2010

Mysterious Energy

"......The studies of distant supernovae by the two teams (led by Saul Perlmutter, an astrophysicist at the University of California) had shown that the expansion of the universe, first observed by Edwin Hubble in 1929, was accelerating - not, as many had predicted, slowing down. It was as if some mysterious energy were creating a repulsive force to counter gravity. Unsure of its exact nature, cosmologists call it dark energy. More important, it seems to constitute nearly three-quarters of the total matter and energy in the universe.

Dark energy is the latest and most daunting puzzle to confront cosmologists, adding to another mystery that has haunted them for decades: dark matter. Nearly 90 percent of the mass of galaxies seems to be made of matter that is unknown and unseen. We know it must be there, for without its gravitational pull the galaxies would have disintegrated.

Perlmutter pointed out that cosmologists in particular, and physicists in general, are now faced with the stark reality that roughly 96 percent of the universe cannot be explained with the theories at hand. All our efforts to understand the material world have illuminated only a tiny fraction of the cosmos."

from 'The Edge of Reason, Dispatches from the Frontiers of Cosmology', (Penguin Books, 2010) by Anil Ananthaswamy (he was a software engineer in Silicon Valley before moving to science writing)

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