NASA astronomers have discovered five planets around 55 Cancri, a sun-like star which lies 41 light years away in the constellation of Cancer. While over 260 such exosolar planets have been discovered, what is significant in the recent discovery is that one of the planets lies in what is called the habitable zone. It is situated at a distance from its star which is conducive for life in terms of temperature that allows water to stay liquid. This planet, however is bigger than Earth, almost the size of Saturn and that rules out its chances for human-like life. But there is speculation about it having moons that could be the right size to harbour life – life as we know, life that depends on water, life that is largely organic.
Considering that even some planets in the solar system were discovered in the last century, it emphasises the difficulty of searching for planets beyond. Given the distances, the light is faint and cannot be seen except with powerful telescopes. In more instances, planets are being detected by indirect means through observing the movement of the star. Methods of observation have improved vastly, allowing man to peer as far back in time like when the Big Bang occurred. Even the Seti programme that began with a telescope of small dimensions scanning the sky in infinitesimal patches, and observed around hundred stars at a few hundred light years away, is now is looking to a faster detection system, thanks to the completion of the Allen telescope array.
However, the bigger question in this quest is why intelligent life, if any, has not contacted us so far. As Italian physicist Enrico Fermi asked “where are they?” He was one who opined that if technologically advanced civilisations are common in the universe, then they should be detectable in one way or another. Going by the sheer size and age of our universe, it is logical to assume that such civilisations exist. But lack of evidence implies that they don’t, or that our observations are inadequate. Or that we are looking for the wrong indicators for such life! The search goes on. Meanwhile, it is worth pondering over a doubt voiced in an editorial in Nature last year. Are we sure that all extraterrestrial civilisations will be benign?
