Astrobiology: A New Word For Your Ears

Introduction:

Majority of the people haven’t heard of this word, and if they did, they might be curious to know about this word. For all those who have heard and haven’t heard of this field, let me tell you that Astrobiology is a 30-year-old field. It was 1992 when the birth of this field took place when 2 NASA scientists, Aleksander Wolszczan and Dale Frail discovered an exoplanet that was revolving around a binary star system. But it was not considered as a true exoplanet. In 1995, the first ever true exoplanet was discovered by Didier Queloz and Michel Mayor. The exoplanet was revolving around a sun-like star and this discovery marked the beginning of the field of Astrobiology which is almost 30 years old as of now.

Exoplanets:

 Exoplanets are a very important part of the field of Astrobiology. An exoplanet is an earth-like planet that is present outside our solar system and is revolving around a sun-like star. So by understanding what an exoplanet really is, we can now say why the exoplanet discovered in 1992 was not considered as a true exoplanet and the later one discovered in 1995 was considered as a true exoplanet. There are several methods to detect and identify the exoplanets. Kepler Telescope, which was sent by NASA in 2009 in space in search of exoplanets has identified more than 2600 exoplanets that are from outside of our solar system and till now, more than 5000 exoplanets have been discovered. Exoplanets are those planets which are earth-like planets and could have the possibility of life on it or have the environmental conditions that can support life on that respective planet. We also have some planets and moons that are present in our solar system that we think have the environmental conditions that can sustain life like Mars, Saturn’s moon Titan, etc. and to make this thinking a reality, several missions are carried out by space agencies worldwide. But these planets and moons are not considered an exoplanets because they are a part of our solar system.

Transition from Exobiology to Astrobiology:

Exobiology and Astrobiology, when we hear these two words, we think that both have the same meaning; both are the same but that’s not the case. Exobiology and Astrobiology are different. Exobiology usually investigates the potential of extraterrestrial life while astrobiology weaves a complex web of life's creation, evolution, and distribution throughout the wide canvas of the cosmos. We can say that Exobiology is a subset of Astrobiology. The shift from exobiology to astrobiology is more than just a change of focus; it is an invitation to participate in the grand story of life's cosmic journey.

Biosignatures:

We all have heard about fossils and we all know what it is. Fossils are the preserved parts of an organism or the whole organism that had lived in the past. Fossils give us evidence about what kind of life has lived on the Earth in the past. They tell us about the past environment (palaeoenvironment), organism morphology, their food dependence, etc. So we can say that fossils are a sign of life on the Earth in the past. These are known as Biosignatures. The term ‘Biosignatures’ refers to any kind of evidence that could indicate or give us a possibility of life or habitable environment on Earth and other Planets and Moons in the present or the past. Some people think that Mars was an Earth-like blue planet billions of years ago and life existed on it, but when we look at Mars today, we just see a red dry planet. The space agencies across countries which are carrying out space missions to Mars in the form of Rovers and Satellites are looking for Biosignatures on Mars. The primary aim to send missions to Mars is to look out for Biosignatures so that they can get an idea about its environment’s habitability and the presence of life. The secondary aims can include the study of the of sending, Martian surface, its tectonics and the mineral and rock composition.

Extreme Life:

‘Charles Darwin’, is a name which we all have heard in our school books. He is considered the ‘Father of Evolution’ and has given several popular theories like ‘Survival of the Fittest’ and ‘Theory of Natural Selection’. He is the man behind the book ‘Homo Sapiens’. Wondering why I am talking about him? Because he is the man who gave us a new way of thinking about the Evolution of Life. Well, for life to survive on Earth, it has to face many challenges, and only those who survive have overcome those challenges. Life’s never easy. To survive, life has to tackle all the problems. The cyanobacteria, which is considered as the first and oldest living organism on Earth, has overcome all those challenges and thus we, ‘The Humans’ are living on this planet. If that bacteria hadn’t survived the extreme conditions of climate, atmosphere, etc. life wouldn’t have evolved on Earth the way it is now. 

The organisms that can survive in the extremest condition are known as ‘Extremophiles’. The common example of Extremophiles is Tardigrades. Tardigrades are known as water bears or moss piglets are a phylum of eight-legged segmented micro-animals.They have a powerful adaptation that allows them to survive for decades in extreme conditions. To endure environmental stress, tardigrades suspend their metabolism through a process called ‘cryptobiosis’.

The image shown is of a ‘Tardigrade’.

Tardigrades are organisms which have survived all the mass extinctions and can go without water for 10 years. It can survive in extreme environments such as icy cold Antarctica or high-pressurethat Mariana Trench as oxygen level does not matter to them much.

The Drake Equation:

There are around 8.7 million species of organisms living on the Earth and still, there is a possibility of new species to be discovered. But there is no particular equation defined to get the possibility of the unknown species that are yet to be discovered. But, there is an equation that gives us the probability of life outside our Planet Earth. This equation is known as ‘The Drake Equation’.

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The thought - ‘Are we alone in this universe?’ gets us the feeling of both excitement and being scared. Drake’s equation is an answer to that. The Drake Equation is a mathematical formula for the possibility of finding life or advanced civilizations in the universe.

Conclusion:

Astrobiology is not a single field but is a combination of six different fields - Physics, Chemistry, Maths, Biology, Geology, and Astronomy. The six fields combine in a way giving rise to the field of Astrobiology. This field is like a flowing river which will find its way even though an obstacle is present in front of it.

I can conclude that Astrobiology, though it is only a 30-year-old field and not being heard by so many people, has a lot of potential soon. All the experts in their respective fields, whether it is Physics, Maths, Biology, Chemistry, Geology, or Astronomy, will come together to work in this field and will give this field a new shape. The field will not evolve like other fields but it will evolve like an explosive field.