By: Pratyasha Priyadarshini
October 19, 2017: Robert Weryck, a post-doctoral researcher from the University of Hawaii’s Institute for Astronomy came across a peculiar object while searching for Earth-approaching asteroids. It was cigar shaped and rotating in a very unusual orbit. It immediately sparked the image of the cylindrical alien spacecraft ‘Rama’ from Arthur C. Clarke’s popular Sci-Fi novel “A rendezvous with Rama”. Everyone began to wonder whether fiction was going to turn into reality. The object was finally determined to be a comet that originated outside our solar system and which happened to fly by the sun. Yet, scientists are curious to know more about its origin; whether it’s natural or artificial, even if it has surpassed the range of our most powerful telescopes. This brings back the age-old debate;
Are we alone in the vast expanse of this universe?
(courtesy- M. Kornmesser/European Southern Observatory)
Long ago, humans started wondering whether Earth was the only planet in the solar system to harbour life. Moon was the next obvious candidate which seemed likely to hold some secrets of its own. NASA’s Moon Mineralogy Mapper (M3) instrument aboard ISRO’s Chandrayaan-1 confirmed the presence of ice caps in both poles of the Moon which was enough to again spark an interest in further lunar explorations. But, it was not the only landmark discovery regarding the possibility of life outside earth. In 2005, NASA’s Cassini spacecraft sent images of Saturn’s moon Enceladus containing geysers of frozen water. Saturn’s biggest moon, Titan is reported to have lakes of liquid natural gases ( ethane and methane) constantly filled up by hydrocarbon rain. The hunt for water on Mars has taken almost 15 years to yield solid evidence of its existence in liquid state. We can’t absolutely deny the presence of some form of microbial life in some regions of Mars a few million years ago. Jupiter’s three famous moons: Europa, Callisto and Ganymede likely contain buried liquid oceans and we can only imagine what lurks beneath. All these places may not accommodate all the conditions that made life possible on Earth. But, hey, why should the aliens look like or be like us ? Even a tiny bacteria swimming in the methane lakes of Titan is an extraterrestrial lifeform, or what if it looks like Master Yoda?
Artist’s impression of Cassini flying by Enceladus
The Search for Extra Terrestrial Intelligence (SETI) institute encourages collaborative scientific efforts all around the world for the exploration of intelligent lifeforms not just inside the solar system, but in the vast expanse of the universe out there. Its ongoing searches, with the help of Allen Telescope Array (ATA), SERENDIP, Breakthrough Listen, FAST and many more, employ radio frequencies as this range of frequencies penetrate the earth’s atmosphere quite effectively. Apart from that, various optical and gamma-ray experiments are carried out alongside in case the aliens might be using powerful laser sources or gamma-ray bursts. The ATA is surveying tens of thousands of red dwarf stars, which are believed to possess characteristics that make them primary targets in the search for intelligent life. The Institute is also keenly examining newly-discovered exoplanets (planets that orbit around other stars) found in their star’s habitable zone. Speaking of exoplanets, it was the Kepler Space Telescope by NASA that searched dedicatedly for exoplanets. It helped astronomers discover 2682 exoplanets during its tenure from March 2009 to November 2018 and many others are still in the waiting list. Before the Kepler telescope, astronomers had managed to find gas-giants like Jupiter in other star systems. Addition of this powerful planet-hunting observatory in space made it easier to find super-Earths (a bit larger than Earth in size with a rocky surface). Transiting Exoplanet Survey Satellite (TESS) launched on 18th April 2018 is the successor to Kepler Telescope after the latter got officially decommissioned on 15th November 2018.
Artist’s impression of Kepler Telescope
You must be wondering, what exactly makes a planet habitable? How do we decide where life can blossom? This question bothered someone else as well. Frank Drake, a radio astronomer at the National Radio Astronomy Observatory in Green Bank, West Virginia came up with a novel approach to combine all the factors that may contribute to the presence of advanced technological civilizations in our galaxy. Trending just below Einstein’s famous energy mass equation, Drake’s equation has emerged as a prominent tool in astrobiology.
Looks terrifying, doesn’t it? Enough mathematics for now, let’s consider some other interesting factors. In a previous passage, I stressed on the fact that aliens need not be like us humans. Note that all the communications we are trying to establish, are intelligent by our standard. Are they decipherable by them? For all the pride Homo Sapiens takes in being the most intelligent creature on the face of the Earth, we are now slowly discovering complex communication patterns in other animals which live in groups, e.g.- elephants, whales, bees etc. Various groups of scientists are engaged in trying to demystify their languages as these might come in handy while sending messages to our celestial neighbours. Some recent reports suggest that life exists in the depths of oceans which have drastically different living conditions as compared to near-surface areas. If the Mariana Trench can be habitable, why not a planet or its satellite exhibiting a similar atmosphere? Climate change poses a very real threat to the biodiversity on our beloved earth. It has caused the extinction of several species on Earth. Is there a possibility that the same fate befell the creatures that once lived in Mars?
Ever heard about Panspermia? According to Wikipedia, it’s the theory that life on the Earth originated from microorganisms and chemicals that were present in outer space. These may have been capable of initiating life on reaching a suitable environment. Though we are yet to get an experimental confirmation, many scientists are actively investigating this wild theory. Then, does that make us aliens? Food for thought.