From understanding the creatures around himself to looking for them beyond the Earth, man has indeed gone a long way. We began with a million questions and a handful of answers. We eventually learnt to find the answers too, leading to the emergence of our ever-evolving technology. Today, even amidst the widely popular view that the conditions on the Earth are unique and delicately-balanced, astronomy has joined hands with biochemistry and molecular biology to predict and look for unexpected life formations elsewhere in the outer space.
Astrobiology is an interdisciplinary field of science that focuses on looking for signs of origin and evolution of life along with their distribution and future, in the universe. It is an integration of the vastly diverse fields of astronomy, physical cosmology, exoplanetology, geology, and, molecular biology, biochemistry, biophysics and chemistry. These fields are instrumental in investing the possibility of emergence and existence of biospheres similar or even different from that on the Earth on other distant exoplanets (planets beyond our solar system) or on the moons of other planets in our own solar system. Astrobiology also includes the study of abiogenesis and early life on the Earth itself, while a closely associated term, exobiology, focuses exclusively on extra-terrestrial life.
NASA funded its first exobiology project in 1959 and, in 1960, founded its first Exobiology Program, which is one of the four main elements of its current Astrobiology Program. In 1971, NASA also funded the Search for Extra-Terrestrial Intelligence (SETI) which set out to look for chances of interstellar communications with and from extraterrestrial life outside the Solar System. Among the many directions which this search has taken, spearheading them all is the search for life on Mars. Mars has piqued the interests of scientists because of its close proximity to the Earth and its geological history. In 1976, NASA launched the Viking Missions to Mars with three biology experiments that aimed to look for the metabolism of life present on Mars, but the results were inconclusive. After many cancelled and failed missions launched by both the NASA and the European Space Agency, in November 2011, NASA launched the Mars Science Laboratory mission carrying the Curiosity rover which is currently roving the planet for past and present signs of habitation of microbial life on Mars. The NASA’s Kepler Mission, launched in March 2009 searches for extrasolar planets, lending a hand to the search as well.
Studies conducted on space debris (for example, from the Tagish lake from Northern British Columbia) suggests that hydro-synthesis is possible on meteorites leading to the formation of organic compounds like amino acids and carboxylic acids. Extremophiles, that is ancient bacteria, found to be growing in near-freezing temperatures in the Cascade Mountains of Oregon in 2011, with little access to oxygen and no organic food point to the possible existence of similar life on Mars, which has similar conditions. In 2017, the Naica mines in Chihuahua, Mexico yielded microbes that have been surviving on sulphite, copper oxide and manganese inside meters-long gypsum crystals, in a state of suspended animation, which are estimated to have originated some 60,000 years ago.
The sky and the space beyond has always been a source of fascination for all Earth-bound creatures since the days of primordial comprehension. With the recent leaps in cosmology and biology, the prospect of reaching out to existing intelligence elsewhere in the universe has become more and more enticing. The future holds a lot of scope for astrobiology. This field will not only expand our horizons when it comes to understanding this cosmos that we inhabit, it will also help shed light on the very genesis of life on our own planet.
