Are we alone in the universe? Is there some other being on some distinct planet asking the same question? Is that civilization more advanced than ours? On Oct. 9, 1992, NASA inaugurated a special program, the Search for Extra-terrestrial Intelligence (SETI), designed to find that civilisation.
The plan was that if a civilisation becomes technologically equipped, it will try and make its presence felt to the species of other world. As a civilisation, we have already reached that point. SETI, however, is more interested in the technological broadcast of life’s existence.
In 1901, Guglielmo Marconi did the first transatlantic radio broadcast. These low powered radio waves that were emitted in that broadcast have now travelled for about 118 years towards the stars. Over the years, our broadcasts too have been spread across the electromagnetic spectrum.
As we are broadcasting to other civilisations, then maybe others are too? If so, this mission aims to catch their signals – the first evidence to prove that we are not the only inhabitants of this universe. Different groups of scientists have been searching for this evidence since past many years using ever more advanced tools and techniques.
Initially, our search for alien life were focused at our own solar system. For that purpose, USA celebrated the National Radio Silence Day during a particularly close approach between Earth and Mars in August 1924. The US government ordered the civilians to maintain radio silence for the first five minutes of every hour for a period of 36 hours. During the silence periods, receivers searched and waited for the signals from the Martians. None came.
With the passage of time and advancement of technology, our efforts to detect the signs of extra-terrestrial life also improved. In 1960, under the leadership of famous radio astronomer and astrobiologist Frank Drake, first true modern SETI program began with Project Ozma. This projected aimed to listen to signals from two single nearby sun-like stars – Tau Ceti and Epsilon Eridani Project Ozma, using a large radio telescope. The observations continued for a period of several months. And again we heard nothing.
Search of signals from intelligent aliens have been a high-risk, high-reward program which has continued over the years. The latest addition to the list is the Breakthrough Listen initiative launched by the theoretical physicist Stephen Hawking.
This new search dwarfs all the previous attempts. It will be using the Australian Parkes Radio Telescope, which shall cover ten times the area on the sky, and do that one hundred times faster than its predecessors. The project will not only scan million closet stars but also will search for extra-galactic signals from 100 closet galaxies. All the data taken by Breakthrough Listen will be open and accessible to all.