In residence with aliens
So astronomers constantly search for alien whispers and transmit messages using radio telescopes, writes Prakash Chandra.Updated: Mar 17, 2008 22:01 IST
Do you love your cheese? You could soon be sharing your passion with aliens — on a planet 42 light years away. Seriously. In June, astronomers plan to beam the promo of a cheese brand from a Norwegian high frequency radio telescope: another human attempt to reach out to extraterrestrial life.
The history of trying to signal other worlds using scientific symbols to advertise our own intelligence is long. Even before the discovery of other planetary systems, astronomers guessed such formations were scattered galore across the universe, and that the chemistry of life is hardly unique to Earth. The sheer scale of the universe makes it almost impossible for humans to be alone. And the laws of evolution suggest the development of technically capable civilisations. The maths is so compelling: of the 200 billion stars in the Milky Way galaxy, at least half probably have planets. If each system has, say, five planets, it still makes 500 billion planets out there. And there are a 100 million other galaxies.
So astronomers constantly search for alien whispers and transmit messages using radio telescopes. The characteristics of alien signals would be unmistakable from those sent by some noisy natural source. Pulsars, for instance, spread their radio energy all over the dial — a very inefficient transmission method even the dumbest of ETs wouldn’t consider. In 1960, US astronomer Frank Drake conducted the first Search for Extraterrestrial Intelligence (Seti) project, named Project Ozma. Since then, several potential Seti finds, including one dubbed the ‘Wow’ signal in 1977, were reported. But none turned out to be alien in nature.
Scientists are, however, looking for traces of energy that are hardly there at all. The total amount of energy from outside the solar system ever picked up by all the radio telescopes is less than the energy of a single raindrop falling to ground. Next year, Nasa plans to launch Kepler, a space telescope sensitive enough to detect Earth-like planets. It will scan an incredible 100,000 stars day and night for four years, narrowing the focus for Seti researchers to discern — amid the crackle and hiss of radio waves from space — the equivalent of a faint ‘Hello!’