|An artist’s impression of life on the moon released by NASA
Over the last five years, Satadal Das, a medical microbiologist working at Peerless Hospital in Calcutta, has been studying some of the toughest microbes known to exist on earth. Reared and carefully monitored in his lab, these bugs can withstand temperatures far above that required to boil water. They can endure continuous onslaught by radiation and survive, and even multiply, in extreme trace amounts (amounts that are detectable but not quantifiable) of water, carbon and nitrogen things required in abundant quantities to sustain life on earth.
Das has been keenly observing the microorganisms, but not for medical reasons. He is, in fact, nursing some extraterrestrial ambitions. He is drawing up an ambitious strategy to transplant life on to the moon. Many may find the idea outlandish, but he thinks it may work.
While experts elsewhere are toying with the idea of building gigantic structures, requiring billions of dollars, for eventual human habitation on the moon, Das is putting forward a strategy that involves the services of some of the most primitive life forms that have survived for millions of years on earth. He believes that it may be possible to create an earth-like environment at least in a small area on the lunar surface with the help of these microbes that are capable of withstanding the extreme temperatures, high radiation levels and no or scarce water resources on the moon.
The idea, reported recently in the journal Acta Astronautica, however, still remains on paper. Except for growing the organisms in the lab, the work continues in the realm of theory.
The moon offers a tough environment for supporting life. It has no atmosphere, resulting in objects on the lunar surface constantly being exposed to very high levels of harmful radiation from the sun. Gravity on the moon is just one-sixth of what we experience on earth.
Das, however, thinks that life may be introduced on the moon if certain microbes are drafted. The microbes, the foremost and integral part of the plan, are diatoms, unicellular organisms, such as algae that are believed to have been inhabiting the earth for nearly 200 million years. These algae (which thrive on silicon) are said to have played a role in making the earth liveable by producing oxygen through photosynthesis. Theres evidence that this group of microorganisms survived all mass extinctions that have occurred on the earth, says Das.
Dass first encounter with a silicon-savouring microorganism was in 1982 while studying the lungs of patients of silicosis, a deadly disease caused by the inhalation of silicon dust, found predominantly in people in mining areas. He found that certain bacteria, such as tubercle bacilli, can thrive in silicosis lungs as they have ample quantities of silicon. This, he says, set him thinking about whether it would be possible to exploit these properties shown not just by bacteria but algae and many other microorganisms.
Das divides the task of creating an earth-like condition into several phases. First, algae and similar organisms that can withstand hostile physical and chemical conditions should be sprinkled along a crater near the moons south pole, speculated to have water ice. The site should be carefully selected to protect the microbes from extremely fluctuating temperatures. Reportedly, temperatures on the moon vary from a high of 300 degree Celsius to a low of -180 degree Celsius, depending on the availability of sunlight. The ideal sites would be the deep crevices of a lunar crater, Das says.
Owing to the high silica content on the surface, these organisms can withstand damage from radiation. This has already been proven in laboratories, he says. Silica, found abundantly in sand, is glassy and transparent to visible light, but impermeable to radiation of other kinds.
Subsequently, higher order microorganisms can be employed to complete the process, which he describes as terraforming of the moon. If well insulated, this microenvironment may remain intact for 300,000 years, he claims.
Haym Benaroya, who heads the Center for Structures in eXtreme Environments at Rutgers University in the US, says the idea is food for thought. But whether it can work is still speculative, Benaroya told KnowHow. Benaroya had invited Das to present a paper on all this in the US a couple of years ago.
Microbiologists in India too are not completely convinced. S. Shivaji, a senior scientist at the Centre for Cellular and Molecular Biology, Hyderabad, says there are many gaps in the work. For example, it is difficult to understand how phytoplanktons (algae that Das intends to use) could be grown in the lab without a continuous supply of carbon dioxide, Shivaji says. Phytoplanktons, quite like plants found on land, absorb carbon dioxide from the atmosphere in order to release oxygen.
It may be possible to enrich silicon resistant or tolerant organisms. But a demonstration of the capacity of the organisms to utilise silicon as the sole source of energy will help to strengthen the hypothesis, Shivaji says.
While Shivaji is ready to give Das the benefit of doubt, S Rajarajan, a microbiologist at Presidency College in Chennai, is quite steadfast in his criticism. He feels that such microbes will perish in temperatures that fluctuate so much on a daily basis.
Das counters that his protocol seeks to take care of such extreme conditions. As per the plan, the microbes should be scattered in a crater so that some of them can find out an intersection area between light and shade so that they can thrive easily inside the crevices, and multiply and spread by greenhouse effect.
According to Das, the entire project may take up to 25 years and as much as five to six lunar missions.