A Candle in the Dark

A look on science, politics, religion and events

Physics Nobel

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It’s that month of the year when we honour the men and women who represent the pinnacle of human achievement, marvel at their magnificence, applaud their brilliance and … enough with the eloquence. To get to the point, it’s Nobel Prize time!

The Nobel Prize in physics for 2006 was awarded to two Americans, John C. Mather and George F. Smoot “for their discovery of the black body form and anisotropy of the cosmic microwave background radiation.”

What did they do to get the nobel? Their work helped in providing very strong experimental evidence which supports the hot big-bang model of the universe. Mather and Smoot were involved in analysing the data of the COBE satellite, which was placed on orbit on November 18, 1989

The picture to the left shows the cosmic microwave background spectrum, carefully measured by the FIRAS instrument on the COBE satellite. In fact, this is the most accurately measured spectrum in nature. The error bars are so small, they can’t be drawn on the graph! Also, the data points can’t be seen, because they fit the theoretical curve so perfectly!

Now, the Cosmic microwave background (CMB) is a consequence of the big bang theory. In the beginning, the universe was a hot plasma full of high energy protons, baryons and what not. It was so dense, that even photons couldn’t travel through. As the universe expanded and coooled, the protons and electrons combined to form neutral atoms, and the photons (ie, light) was able to travel freely. So, the theory says that the radiation emitted at that point, was that of a perfect black body from a spherical surface. Look at the graph of intensity vs wavenumber again. It shows that the experimental data collected by COBE, matches absolutely perfectly with the black body graph.

The ansiotropic effects (property of being directionally dependent) of the CMB were predicted by the theory due to scattering at the surface. This was also succesfully measured by the COBE satellite.

Per Carlson, the chairman of the Nobel committee for physics, said

It is one of the greatest discoveries of the century. I would call it the greatest. It increases our knowledge of our place in the universe.

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Written by parseval

October 3, 2006 at 5:40 pm

Posted in nobel prize, physics

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