The great cosmic discovery - V

Prof H Nandakumar Sarma *

The discovery of microwave background radiation, neutron star, pulsar; trying to understand the cosmic forces, the discovery of anisotropy of cosmic microwave background radiation, the discovery of Higgs boson ( God’s particle ), the detection of gravitational wave and black hole etc are some of the exciting moments in the understanding of the universe.

In this series, we trace some of the great cosmic discovery made from the beginning of the 20th century to the present day.

Arno Penzias and Robert Wilson while working with the radio telescope at Crawford Hill of Bell Laboratories observed the radiation coming from cosmos consists of two parts. First, there is the radiation emitted by various stellar sources. Besides this, there is background radiation all around us in the universe corresponding to about 3 degree kelvin (-270 C), (this scale of temperature is also known as absolute scale but usually called Kelvin scale, after the nineteenth century British Physicist Lord Kelvin).

This radiation is almost the same in all directions and is not produced by any source we see today in the sky. Arno Allan Penzias was born in Munich on April 26, 1933. In 1934, as Jews, he and his family were deported by the Nazis from their home in Germany to Poland for extermination.

Fortunately, they managed to return to German shortly after the deportation and migrated to U.S.A. In 1954, he graduated from the City College of New York with a bachelor’s degree in physics. After two years in the U.S.A. Army signal corps he entered graduate school at Columbia University. He received his doctorate in physics from Columbia in 1962 and took a job at Bell Labs.

In the following three years he collaborated with Robert Wilson to make observation of the puzzling cosmic fossil background radiation corresponding to about 3 degree Kelvin, which served as the basis for their Nobel Prize award in 1978.

Robert Woodrow Wilson was born in Houston, Texas, on January 10, 1936. As a young man, he would putter in the machines, electronics and automobile shops of oil service company in Houston where his father was employed as a chemist. After graduation, Wilson went to the California Institute of Technology and continued his studies in physics. Wilson received a doctorate in 1962.

He constructed a low noise maser (microwave amplification by stimulated emission of radiation) amplifier suitable for use in a radio telescope. In 1963, Wilson took a job with Bell Labs and worked with Penzias there.

In 1964, Dicke, who was unaware of George Gamow and his collaborators’ work was also led to speculate that the last Big Bang might have left traces of cosmological radiation and asked P.J .Peebles to calculate its temperature.

The refined calculations of Peebles gave about 3 degree kelvin. Thus, the radiation corresponding to 3 degree kelvin discovered by Arno Penzias and Robert Wilson in 1965 was the fossil of radiation of a Big Bang of the origin of universe some 12 -15 billion years ago.

British astronomer, Fred Hoyle proposed a spirited opponent of the Big Bang theory, the Steady State theory. The comer stone of steady state theory is the overall unchanging observable universe with time i.e. no beginning and no end.

Before the discovery of the microwave background radiation steady state theory had wide acceptance. After the discovery of microwave background radiation corresponding to 3K by Wilson and Penzias, the last nail in the coffin of the steady state theory of the origin of the universe was driven.

For the discovery of the microwave background radiation corresponding to about 3 degree Kelvin Wilson and Penzias shared 1978 Nobel Prize in Physics with Peter Kapitza.