According to Hubble Telescope's observations, our 15 billion years or so old Universe consists of 125 billion galaxies and as many as 6.25 billion life-supporting solar systems like ours. But why haven't we heard from any other extra-terrestrial civilization yet?

For the last 50 years, enthusiasts have been listening out for signals, discernible in the background noise of space, that might point to another civilisation.

Apart from a couple of brief, intriguing events, nothing has really shown up, which has prompted the Search for Extraterrestrial Intelligence (SETT) to shift more and more from "passive" to "active” mode.

We are already spewing out diffuse signals through TV and radio broadcasts that pass through the ionosphere.

With "active SETT", the idea is to use powerful radio astronomy transmitters to beam out to interesting stars or extrasolar planets in the hope of eventually hitting paydirt.

The possibility of the existence of any extraterrestrial intelligence (ETI) was the heart of the discussion at a recently held two-day conference of the Britain's most prestigious scientific organization, 'The Royal Society.' Held on 25 th and 26th January 2010, it was the first ever meeting devoted to

the study of alien life forms during the 350-year history of the Royal Society. The conference was organized to mark the 50th anniversary of the Search for Extra-Terrestrials (SETI) program. According to Lord Rees, president of the Society and Astronomer Royal, the chance of discovering life on other worlds is greater than ever. Lord Rees, also a professor of cosmology and astrophysics at Cambridge University, expressed his views in this international conference. He stressed that over the last decade, technology has undergone sufficient development raising our hopes to discover planets orbiting stars that are complete with all the conditions to sustain life.

It is worthwhile to note that last year NASA launched the Kepler spacecraft, a historic project whose objective was to find Earth-like planets in the Universe. But the celebrated

scientist also warned that the aliens might be very different from what popular sci-fi films project. It is believed that extraterrestrial life forms might be entirely beyond human sensory perceptions. In the words of Lord Rees, "There may be advanced life of a kind we can’t conceive, a kind that doesn't reveal itself by electromagnetic radiation-a kind that isn't communicating at all.”

World's leading astronomers, astrobiologists and astrophysicists from NASA, European Space Agency and UN office of Outer Space Affairs participated in the conference. Paul Davies, a physicist from Arizona State University and a keynote speaker also attended it. He spoke on the possibility of alien microbial life existing right here on earth. This notion has been echoed by the scientists of SETI as well.

Since 1960, SETT has been scouting the heavens hoping to receive any indication if an advanced alien life form exists elsewhere in our galaxy or beyond. However, so far nothing of that sort could be established. Suggesting new ideas for the future of SETI, Paul Davies, in his keynote speech, noted that this is due to the fact that the field of search is simply mind-boggling where radio signals have to travel tens of thousands of light years. Secondly, the exploration is probably aimed at the wrong place, at wrong time and in the wrong way. But complications could be experienced from the other directions as well. Frank Drake, founder member of SETI, who was also present at the conference, explained that the more technologically sophisticated the Earth « gets, the quieter it becomes in 2 terms of emitting signals into 2 space. This makes the chance to detect us harder for any alien civilization searching for other celestial life forms like ourselves. But what would happen, if despite all the challenges a contact were made? What is going to be its social impact?

According to Prof. Albert Harrison of the University of California, despite all the uncertainties and fears that such contact may cause, the discovery is also likely to leave a sobering impact on us, perhaps even delight.