Two years after it made planetfall, Nasa?s Mars rover Curiosity has reached its destination, the base of a three-mile-high feature dubbed Mount Sharp. This will be the site of its main science experiments, an area in which it is perceived to have underperformed.
Science team leader Scott Grotzinger was singled out for attention by NASA?s Planetary Senior Review Panel when the project sought a funding extension of two years. But setting aside the inscrutable politics of planetary science, the panel thought that in order to satiate human curiosity, Curiosity, the rover, should spend more time drilling for rock samples and less time wandering about the Martian landscape. To deliver a return on the $2.5 billion investment, it needs to address the big questions about life, Mars and everything.
Now, Curiosity is going to settle down and start drilling, though the scientific takeaway is not precisely what the majority wants to know: do Martians exist, and do they look like the Martians in Alien Arena (the game) and Mars Attack (the movie)? Inexplicably, there is little curiosity about why the Martians in these two cultural products look almost identical, and what it tells us about humanity, rather than Martian-ness.
The scientific question about Mars is slightly larger than the human question: was the planet ever capable of supporting organic life? There is a practical, commercial dimension to this question: Mars is likely to be the first planet with human settlers (the Mars One project will land four pioneers in 2024) and if it has the chemical makings of life, it should be easier to develop earth-like ecosystems for them.
Humanity?s fascination for life on Mars dates back to 1877, when Giovanni Schiaparelli, director of the Milan Observatory, declared that it was criss-crossed by canals, rather like Venice. In the US, Percival Lowell picked up the thread. Over 15 years, he mapped the perceived canals and popularised the idea that they had been dug to draw water from polar ice caps in a rapidly drying?and dying?planet. In 1909, the Mount Wilson Observatory?s telescope revealed no ?canals? at all, suggesting that they had been mirages produced by optical errors.
Fast-forward to 1976, when two Viking landers touched down on Mars and conducted the first chemical experiments. They appeared to detect something in Martian soil which emitted carbon dioxide, as living things do on earth. The presence of microorganisms was proposed but never proved. In 1996 Allan Hills 84001, a space rock attributed to Mars, caused a sensation when microbial fossils were recovered from it. President Bill Clinton was shaken and stirred into addressing his nation about the finding but physical processes could have also produced the ?fossils?. In 2001 Arthur C Clarke, former chairperson of the British Interplanetary Society and author, coincidentally, of 2001: A Space Odyssey, declared that he had detected trees and vegetation cover in photographs of Mars, or at least something that waxed and waned with the seasons like vegetation. The scientific community respectfully disagreed.
The first credible answers to the big question of planetary science are coming from Curiosity. Last year, it confirmed that the crater in which it landed had been the bed of a freshwater lake a few billion years ago. A medium like water is essential for the processes of life, so this is one piece of the puzzle in place ?if there were microorganisms at the time on Mars, they would have flourished. The discovery of amino acids or complex organic molecules would have been clinching evidence. Carbon dioxide would have suggested the present existence of life. None of this has been found, but powdered rock drilled from an outcrop dubbed John Klein contained carbon, hydrogen, nitrogen and oxygen, the chemical basis of life on earth, and phosphorus besides. From the evidence, the existence of microbial life on Mars may be postulated about 3 billion years ago. That?s roughly 70 million years after the oldest fossil material discovered on earth?Greenland graphite derived from living material.
Let?s put it this way: the existence of life on Mars billions of years ago cannot be ruled out, but the sentient and colonially invasive Martians of Mars Attack and The War of the Worlds are human creations. Practically speaking, there are no Martians who can lay claim to Mars. The planet is there to be colonised.
India is rather behind in the race to Mars. Mangalyaan will reach Mars orbit next week. The immediate focus of the project is engineering, testing telemetry and the ability to execute complex manoeuvres in space, but it will also map the Martian surface and seek methane?a sign of life?in the atmosphere. But the space race could eventually turn into a land-grab. Landers and rovers of our own, perhaps developed in collaboration with other space programmes, are obvious priorities.
pratik.kanjilal@expressindia.com
