On the allure of Mars and what takes us there.
BY G B S N P VARMA
India: 7.59. September 24.
The phrase “traversing the heavens” invokes a romance, our dreams of flight and finding new worlds. We reached one patch of heaven at 07.59 hours on Wednesday September 24, bang on schedule. The dream became reality when Mangalyaan slipped into its parking orbit around Mars.
The Mars Orbiter Mission (MOM), however, is a solid combination of romance and cold calculation. Its path and entry—simulated using high-fidelity mathematics much earlier—unspooled flawlessly in real time, exactly as predicted by its navigators on Earth. At the end of its journey of 680 million kilometres (km)over 10 months, MOM swivelled, triggered its main thrusters to execute a 24-minute braking burn, and dropped its speed to 4 km per second so that it could be captured by Mars’ gravity. So it’s sol 1—the Martian day 1—for MOM.
It’s not alone out there. There are companions from other nations already circling the planet; NASA’s recently-arrived MAVEN, the Mars Odyssey, the Mars Reconnaissance Orbiter, and ESA’s Mars Express. There’s more company on the surface as well: NASA’s rovers, Curiosity and Opportunity, prospecting on the planet. It’s going to get a bit more crowded, with NASA’s plans for a lander in 2016 and a rover in 2020, ESA’s probe in 2016 and a rover in 2018.
What earthly reason could there for this Mars fixation?
“People will go anywhere to get companions, to answer the question: ‘are we alone in the universe?’,” says Sandip Kumar Chakrabarti, senior professor at the S.N. Bose National Centre for Basic Sciences, Kolkata. “Our expedition to Mars is necessary to answer this question.”
The logistics of exploration of the mysterious realms of deep space, though, is beyond us for now. With today’s technology, Chakrabarti says, we will take 40,000 years to get to the nearest star, 3.26 lightyears away. So the relative proximity of Mars to earth makes the planet an attractive go-around.
But it’s not just about the trip, an opportunity to go picnicking on Mars. The planet intrigues us.
Earth and Mars were born at the same time with similar conditions. Later, they went separate ways as if motivated by planetary fraternal grudges. Earth continues be habitable, (although climate change and global warming are fast coming), whereas Mars went from a wet place to frigid wasteland. The question that intrigues scientists is how it happened.
“Mars geology is a dead geology,” says Sujan Kumar Sengupta, associate professor of astronomy at the Indian Institute of Astrophysics, Bangalore. He works on finding planets outside the solar system, extra-solar planets
“If you measure the earth’s temperature from outside the solar system, it’s minus 15 degrees,” he says. But, because of the greenhouse effect, the average temperature hovers between 15 and 20 degrees. Mars, on the other hand, doesn’t have much greenhouse effect, and its temperature remains below zero all the time. Even when it comes close to the sun—since it’s going around the sun in an elliptical orbit—its ice melts, but freezes again, as it moves away from the sun.
To continue this sad litany, there is no magnetic field as there is no geological activity, and thus there is no protection for Mars from the deadly rain of cosmic charged particles as on earth. Charged particles from the sun slam into its atmosphere, ionizing the air. “Even if water was there, these charged particles would have ionised it,” says Sengupta. Moreover, the planet has no ozone layer, as earth has, so ultraviolet rays enter its atmosphere.
“Because there is no ‘Mars-quake’ or volcanic activity, the minerals on Mars and the gases in its atmosphere do not get reprocessed. There is a little quantity of free oxygen molecules but plenty of carbon dioxide. Because of the intense ultra-violet rays, carbon dioxide gets converted into the poisonous carbon monoxide which makes Mars a very hostile place,” explains Sengupta. The atmosphere is also much thinner than Earth’s because Mars has lower gravity.
The spacecraft that are circling and crawling on Mars study how it was formed, its composition, its environment, and in what ways it was transformed.
Sengupta feels planetary science always intrigues. At least, 2,000 planets have been discovered outside our solar system, orbiting different stars.
“My research is to find out if an earth-like planet exist outside our solar system; ultimately, to find out if life exists outside earth,” he says.
The quote on his webpage encapsulates his vision:
“Watch the Earth through a microscope
And you’ll find out how delicate life is;
Watch the Earth through a telescope
And you’ll find out how rare life is.”
Taking a step further than watching through a telescope, four space agencies have sent probes and rovers to find out “how rare life is”.
What fuels the hope of life outside Earth is that Mars could have harboured primitive life forms. In addition, it marginally falls in the Habitable Zone or Goldilocks zone of the sun. The Habitable Zone is the circum-stellar region of a star where temperatures are such that water can exist in liquid form, and thus it is conducive to habitation. The zone extends from Venus to (marginally) Mars, because Mars is in elliptical orbit. (Venus incinerates whatever comes close it.)
In our quest for companions, we would like to know if the Mars atmosphere was more habitable at one point and now it is gone.
“We would love to go or reach out anywhere if we have some hints that there could be life. This would be a one-of-a-kind new discovery since 3.6 billion years ago when single cell life forms emerged on earth,” says Chakrabarti.
Those cell life forms could have emerged only with water. He continues, “It is possible that it may have subterranean flow of water/ice which may have micro fossils of microscopic life forms long gone. The clay on the surface of the Mars is suited to making complex bio-molecules. It is believed that Earth’s life forms could also have formed with clay as the substrate or catalyst. So it would be exciting to understand chemistry with clay material,” he says.
In a momentous discovery in March, NASA’s Curiosity found clay minerals, pointing to the existence of an ancient stream or lake which, Curiosity’s scientists declared, could have supported life.
However, there is no trace of microbial life now, as Curiosity has not found enough methane, a potential signature of life. Methane, naturally formed, gets destroyed fast, leaving no trace; biologically formed, it lingers longer, and so it’s considered an indicator of the presence of life. MOM also has a methane sensor intended for sniffing methane in some place while circumambulating around Mars.
So the search for companion life continues. “Mars exploration is our expression of our frustration that perhaps we will never know the answer to the basic question, ‘are we alone in the universe?’ even though statistically we know there should be at least 1,00,000 places in our galaxy alone that can harbour civilised life forms. But we can’t reach them. Mars is our only hope,” Chakrabarti says.
(G B S N P Varma is a freelance journalist based in Andhra Pradesh.)
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