Environment Science Space Tech

Astrobiology — The Latest Supernova

"No solid proof of life outside our atmosphere is available, yet. This is where astrobiology steps in."
By Rajvi Parekh

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Carl Sagan poses with a model of the Viking Lander in Death Valley, California (Image: “Cosmos – A Personal Voyage”)

The standard Hollywood attempts are to portray the extraterrestrials as red of claw and fang. Pointed heads and nasty dispositions. Steven Spielberg has made an important step forward. “E.T.” and “Close Encounters of the Third Kind” … to show the possibility of benign extraterrestrials, but even there, the extraterrestrials are only slight variants on human beings when the evolutionary record is clear that extraterrestrials would be very different from us. Also they’re not awfully smart, his extraterrestrials.

Carl Sagan

From centuries-old engravings of “fiery discs” to grainy footage from the 20th century, from Cosmos to Ancient Aliens, from Roswell to Gorakhpur, we have been mesmerized with the idea of strange, teratoid creatures from outer space paying visits to our lush planet. We have all, from kids to stoic adults, wondered, “Are we alone in this entire universe? Are there people like us in the universe? Better than us? Friendly? Will their arrival cause our destruction?” We are evidently light years away from finding vertebrate aliens, finding civilizations in places in our solar system itself, but we have started venturing beyond our planet’s atmosphere, and how.

Humankind’s imagination and creativity sculpted science fiction, which has slowly become a reality intertwined with popular culture. The Voyager-I spacecraft launched by NASA in 1977 is our planet’s furthest travelling man-made object in space. Voyager-I and II have been sending data and images to Earth since 2013 as they finally entered interstellar space — around 35 years after launch — and today, we have the Mangalyaan, Cassini and Juno space probes fascinating us with images of Mars, Saturn and Jupiter respectively. Apart from these popular instances, space organisations from different countries have probed a number of bodies in the solar system, no pun intended. We have an almost-clear idea of the surfaces of the planets and their moons in the solar system.

Which leads us to think, is anyone out there? If yes, what are they? If no, shall we live there? Before our sci-fi fantasies of colonisation, war and intergalactic love are fulfilled, a comprehensive canvassing of the handful of candidates we have in our solar system needs to be carried out. No solid proof of life outside our atmosphere is available, yet. This is where astrobiology steps in.

What is Astrobiology?

Astrobiology is defined by NASA as, “The study of the origin, evolution, distribution, and future of life in the universe.” This field of study covers not only the discovery of extraterrestrial life, but the minutest evidence of biotic nature present in inhabitable and extreme environments beyond Earth. Astrobiology searches for the answers to three questions – “How did life originate and evolve?”, “Are we alone?”, and “What is the future of life beyond earth?” Strategies in space research are no longer limited to making rockets and shooting them into the abyss, but also examining alien environments and deducing their ancient turfs, searching habitable worlds, and studying the evolution of our own planet — which is an exhaustive, interdisciplinary study of organic chemistry, genomics, biology and physics.

What does Astrobiology do?

Since research in Astrobiology has just started, to prevent it from becoming nebulous, researchers in the community have chalked out a few major goals and objectives, with several sub-objectives under each of these. Considering the three golden questions asked previously, the objectives to expand research on are as follows:

  • Identifying abiotic sources of organic compounds
  • Synthesis and function of macromolecules in the origin of life
  • Early life and increasing complexity
  • Co-evolution of life and the physical environment
  • Identifying, exploring, and characterizing environments for habitability and biosignatures
  • Constructing habitable worlds

To simplify these objectives, what astrobiologists are doing is starting right at Earth’s terrain, going to the stars, and embracing everything in between. Scientists are searching for the exact events, the exact molecules that triggered the continuous journey of evolution. We emerged from a soup of molecules, and now they are searching for the accidents or planned events that produced it. They are also searching for the events that caused these molecules to fit like Lego blocks and form what are proteins and DNA, the stuff which makes us and every other living creature on this planet. This, coupled with evolutionary biology, provides researchers with a template which can then be compared with events occurring on moons and planets around us, further helping us understand if evolution follows a fixed pattern, if carbon atoms make up life outside Earth, and if DNA molecules are the masters of creating life elsewhere.

In parallel, astrobiologists are combing through our neighbours in the solar system for any sign of previous life, as well as a factor or two which proves them to be habitable for humans. These factors include — you guessed it — any reserve of water, a deposit of vital gases like oxygen and methane, and organic regolith — untouched solid material on a planet’s surface — which is similar in composition to Earth’s soil. All this makes astrobiology more than just an airy buzzword; it makes an intensive, exhausting and deeply interesting field of study.


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An enhanced colour view of Jupiter’s moon Europa from the Galileo spacecraft. (Image: NASA JPL / SETI Institute)

Is there Life on Mars? (And Saturn, Jupiter, Titan?)

David Bowie crooned pensively if there was life on our neighbour in 1971. Scientists today croon the same, except now they’ve broadened their area of research to other planets and their moons. The Astrobiology Program by NASA has six divisions: the NASA Astrobiology Institute, Exobiology & Evolutionary Biology, Planetary Science & Technology Through Analog Research, MatiSSE, PICASSO, and the Habitable Worlds Program. NASA officially established an astrobiology program in 1996, but the Exobiology program was created and functional since the 60s. Exobiology is too specific a term which includes the study of extraterrestrial life and its effects on Earth, while astrobiology includes that as well as evolutionary sciences, planetary sciences, earth sciences, astrophysics, and heliophysics, the studies related to the Sun.

Astrobiologists have adopted extensive methodologies which include arrays of telescopes that scan the energies and radiation emerging from celestial bodies and verify their sources, such as the Atacama Large Millimeter Array (constructed through a partnership of many countries) and the European Space Agency’s far-infrared space telescope Herschel, and planetary surface rovers and landers which carry mobile laboratories to perform experiments on planet terrain — like Viking and Beagle 2 — and the EXPOSE in lower Earth orbit. A full list of missions from the past and present are available on NASA’s astrobiology website.

What we desire from astrobiology research are obviously monolithic civilizations, gargantuan aliens, and a hangar for those damned flying saucers. Realistically, we are not getting them anytime soon. Meanwhile, scientists are equipped with fine-toothed combs and magnifying glasses. Life on Earth started from a mixture of molecules and proceeded to form a single cell. The journey from that to a human being took billions of years. Speculatively, as well as evidently, it is believed that a barren planet with polar ice caps, like Mars, could positively be on the road to evolution just as Earth, or negatively, have had a civilization in the past which has been entirely obliterated. Meaning Mars could have its own unique road map toward evolution, or could be just a lifeless frozen rock.

Mars is not the only potential candidate for research in our solar system. Jupiter’s moon Europa is covered with an icy crust, but beneath it lies a liquid environment which contains more water than Earth’s entire hydrosphere. Some corners of pseudoscience even claim that dolphins and other aquatic creatures might be thriving in those waters. Similarly, Saturn’s moon Enceladus possibly has a boiling ocean and mixtures of simple organic molecules underneath an icy layer. Saturn’s other moon, Titan — also its largest — shows the presence of methane gas which, on our planet, is the by-product of metabolic processes of many a living creature.


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Saturn’s moon Titan, as captured by the Cassini spacecraft. (Image: NASA JPL)

As for alien creatures, what scientists look for is not someone of our build and gait. They are smaller, microscopic in appearance, but much more powerful. Welcome to the world of extremophilic microorganisms! Microbes such as bacteria, fungi, cyanobacteria, algae and others are documented to live in places humans cannot physically survive, such as deep ocean trenches, extreme sub-zero climates, toxic waste pools, dry deserts, acidic hot water springs and your intestines. Organisms capable of living in such harsh conditions are known as extremophiles (philia meaning extreme fondness) and a number of species will be tested for their capabilities to survive in the uncomfortable conditions of outer space in the future. There are ongoing studies to search for similar organisms outside our atmosphere, which sounds just as interesting but more feasible than searching for six-foot tall reptilians. On our planet, certain organisms thrive even in radiation levels which kill us. Our planet plays host to microorganisms which thrive in high radiation, extreme temperatures and even highly acidic and alkaline environments.

Tardigrades (or Water Bears) can survive under high radiation levels, extreme temperatures such as hot springs, extreme pressures such as deep underwater, and even the deathly vacuum of outer space. This makes them a prime candidate for biological experiments in space. Thermus aquaticus live in boiling hot conditions, found near geysers, while Chryseobacterium greenlandensis is an example of an organism that lives in freezing conditions of -20 degrees C and below. And we think us puny humans are the fittest.


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Coloured Scanning Electron Micrograph (SEM) of a water bear (Paramacrobiotus craterlaki) in moss.

The Indian Astrobiology Research Centre has proposed a unique mission in the form of a concept note, called “Bijayan Venus” (bij = seed). The mission will involve a nano-spacecraft constructed in Mumbai and Surat, and will transport genetically marked, non-pathogenic extremophiles to the surface of Venus. Venus, till date, shows no evidence of life and, in fact, has a particularly hostile environment, detailed in Carl Sagan’s Cosmos. It is therefore an interesting location to check the habitability of extremophilic microbial life, and a possible impetus to Venusian evolution. The concept note can be viewed here and updates on the mission are expected soon.

Speculation on extraterrestrial life and the search for the unknown in the deep night have been prevalent since human species learned to look at the sky. Astronomy, let alone astrobiology, has only recently flourished, and we are still taking baby steps. Elon Musk ideating space travel, growing potatoes on Mars, and E.T. (or even Jadoo) are distant visions, but they are not at all impossible. While space organisations in our country and all over the world work towards searching for life and establishing a habitable solar system and beyond, us citizens of the planet can dream about being benign citizens with extraterrestrial microbes. And maybe about silly dolphins on Europa.


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The writer, Rajvi Parekh, is an author and scientist from Mumbai. She specialises in microbiology, and in her free time writes about the biological sciences.

Tweet at Rajvi: @floweraldehyde



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2 comments

  1. Why did no one ever go back to the moon? Or did anyone ever really go there? I need to get a telescope(for beginners) and put in a little more research on this topic. Can spacecrafts cross that Van Allen belt? As i said need to put in my own research. Had one more question(never found a answer for this) – when we take a flight at night why can’t we see stars?

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