Nobel Laureate’s Work Shows A ‘Baby Picture of the Universe’

UC Berkeley physics professor George Smoot and NASA scientist John Mather were awarded Tuesday the Nobel Prize in physics for "their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation," according to the Nobel committee's citation.

Smoot and Mather discovered evidence that scientists used to study and solidify the big-bang theory.

Smoot studied cosmic microwave background radiation, which refers to a form of radiation that was emitted from the big-bang explosion.

"If you wind the movie of the universe back, the universe becomes very small and very hot," said UC Berkeley assistant physics professor Adrian Lee, who also studies cosmic microwave background radiation. "It's as if you took a balloon and you compressed it and you made it very small, you would get a very small, very hot, a very dense state."

During this period, the hot, dense state was in thermal equilibrium at a temperature of 3000 degrees Kelvin.

However, as the universe expanded, the leftover remnant radiation from that time period began to cool down. Smoot discovered that overall the radiation waves were now a little more than 2 degrees Kelvin.

In addition, the cosmic background radiation had minute variations in temperature.

"It was predicted that there were these very faint fluctuations in that radiation, so that if you could look up in the sky, you could see in the sky some parts were hotter than others, like a leopard skin of hot spots and cold spots," Lee said.

The fluctuations were predicted by many astrophysicists, but never proven until an experiment led by Smoot revealed the data that supported the theory. Smoot relied on measurements taken by the Cosmic Background Explorer satellite, which was launched by NASA in 1989.

The fluctuations are significant because they reflect the beginnings of the universe's structure. Using the data, Smoot was able to create a map of the "young" 300,000-year-old universe, detailing the cosmic microwave background radiation as well as the hot and cold regions.

"Basically the (satellite's) map is a baby picture of the universe, a snapshot of the universe when the universe was a baby," Lee said.

The Nobel Prize committee awarded Mather for his work on the blackbody spectrum, which offers insight into the universe when it was at thermal equilibrium.

"If you have some object, say a potato, and it's all at one temperature, then quantum mechanics predict a very particular spectrum of radiation from that potato," Lee said. "And so the universe was also predicted to have this spectrum called a blackbody spectrum."

The blackbody spectrum along with Smoot's discovery of the radiation's fluctuations have been used to explain the origins of the universe.

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