Friday, March 17, 2006

Sach Kee Baani Nanak Aakhe

Sach Sunae see sach kee Bela,


POLARIZED PICTURE. New measurements of the polarization (white lines) of the radiation left over from the Big Bang,
combined with a map of hot and cold spots in the background.
The new data confirms with unprecedented accuracy the

ingredients of the universe:
4.4 percent ordinary matter, or atoms,
22 percent invisible material ( dark matter )
74 percent a mysterious entity ( dark energy )

The satellite also pegs the age of the universe at 13.7 billion years.
Previous results from the satellite focused on the variations in the temperature of the
microwave-background radiation, which has cooled over billions of years to a frigid 2.72 kelvins. Tiny variations in that temperature, less than a millionth of a kelvin hotter or colder, revealed details of the primordial density fluctuations that gave rise to stars and galaxies (SN: 2/15/03, p. 99:
http://www.sciencenews.org/articles/20030215/fob1.asp). The new results focus on the polarization of the microwave-background radiation, the tendency of the radiation's waves to vibrate in a specific direction.

The polarization signal reveals that the first stars formed 300 to 400 million years after the Big Bang.
That's slightly later than estimates that were based on earlier data from the same satellite, notes cosmologist Michael Turner of the University of Chicago.

Accounting for the polarization was like "removing a fog," says Spergel. It enabled the team to scrutinize more closely than ever before the primordial fluctuations imprinted on the microwave background.

According to the simplest model of inflation, the universe didn't balloon at a constant rate during the early growth spurt.

As a consequence, variations in density of matter in the universe ought to be slightly
larger on the largest scales—10 billion light-years—than on smaller scales—roughly 100 million
light-years. The satellite has now found exactly that pattern, the team reports.
"This is not simply another test of inflation but something that examines the universe during its first trillionth of a trillionth of a second," says Turner. "The entire cosmology community has been waiting for this, excited and worried." The findings "are beginning to shed light on the mechanism [that drove] inflation," he adds.





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