The Hindu : Is there life on Mars?

Online edition of India's National Newspaper
Tuesday, Dec 30, 2003

Opinion

Opinion - Editorials

Is there life on Mars?

LIFE ON MARS has been a long-time human preoccupation. The late 19th century Italian astronomer, Giovanni Schiaparelli, thought he saw "canali" (meaning channels) on the Martian surface, and the word got misinterpreted to mean canals. His contemporary, Percival Lowell, a wealthy American amateur astronomer, was convinced after studying Mars through a telescope for 15 years that the straight lines he saw on that planet were undoubtedly canals constructed by intelligent beings. The prospect gripped lay people and scientists alike, and writers and film-makers were quick to pounce on its dramatic possibilities. If there were intelligent beings over on Mars, who could say that they would not one day try to take over Earth and enslave its people? So when a radio dramatisation of H.G. Wells' book, War of the Worlds, was broadcast in the United States in 1938, the public was quite prepared to believe that the Martians were invading and panic ensued.

With the coming of the space age, instead of the Martians coming to Earth, humans sent probe after probe to that planet. Over 30 scientific satellites and landers have been despatched to Mars in the past four decades, although two-thirds of them failed somewhere along the way. The United States currently has two satellites mapping Mars and studying its chemical makeup. Europe's Mars Express, with the Beagle 2 lander, is just the latest to arrive. Right behind are two robotic rovers from the United States that will reach the planet next month and prowl about on its surface. Japan's Nozomi spacecraft would have been part of the throng around Mars but for the problems it developed en route. The two Mariner spacecraft, which reached Mars in 1969, were the first to send back closeup images of that planet. Those photographs dispelled notions of vegetation flourishing there. A decade later, when the Viking landers touched down on its surface, there were no Martians to be seen and there was indeed no trace of life. Mars is actually a rather forbidding place, arid, bitterly cold, with a thin atmosphere made up largely of carbon dioxide and bathed in strong ultraviolet light. Life in such an environment would seem improbable, if not impossible. Yet human obsession with Martian life refuses to die out. Exotic Martians with strange body-forms are out of the question, but hardy microbes might eke out an existence, say scientists. Mars may have been a very different place over three and a half billion years ago, they point out. Back then, Mars may have been warmer and wetter than it is today. The deep gullies and ravines still visible on the planet were probably etched by running water. With liquid water and a more benign climate, microbial life could conceivably have arisen on Mars, as happened on Earth.

But that is speculation, and finding proof is not going to be easy. Liquid water no longer flows on the Martian surface. Much of the water known to exist on Mars is locked away as ice at the polar caps. If there is water below the surface, in the pores of rocks and when the iced water melts in summer, Martian microbes may be able to cling to life, like bacteria which inhabit extreme environments on Earth. Locating sources of liquid water on Mars is a major objective for the scientific satellites and landers. If there are no living microbes, establishing that life once existed on that planet could be just as difficult. But even if no trace of life, past or present, is ever found there, the search will refine our skill in looking for life elsewhere in the solar system and beyond.

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