Chemical Conditions just like on the Early Earth were discovered on some Exoplanets

Chemical Conditions just like on the Early Earth were discovered on some Exoplanets

Researchers believe that the intensity of Ultraviolet light has a vital role in developing life on a planet.

The ever-increasing hostility of the Earth’s climate has urged the scientists to search for an alternative habitat for humanity. Consequently, they are scanning every nook and corner of the universe to find any signs of life. Simultaneously, efforts are being made to understand the events that led to the beginning of life on our planet. Thousands of Exoplanets have been categorized as potential candidates by making use of all the advanced technologies including Kepler Telescope of NASA. A recent progress in this regard came from the collaboration of researchers from the Medical Research Council Laboratory of Molecular Biology (MRCLMB) and the University of Cambridge.

They found a group of Exoplanets with chemical conditions similar to what Earth might have had during its early days. They observed that the development of life on a planet is dependent on the type and strength of the light given by its host star. According to their findings published in the journal ‘Science Advances’, the planets orbiting around a star, which emits ultraviolet light of sufficient intensity, have higher chances of supporting life. They mentioned that the ultraviolet (UV) light initiates a series of chemical reactions responsible for producing building blocks of life.

The work of Professor John Sutherland provided the basis for this research. He studies the chemical origin of life on Earth and is also a co-author of the latest study. It provided the researchers with a substantial number of Exoplanets that lie in the Goldilocks Zone and get sufficient energy from their host stars. Goldilocks Zone refers to the habitable region around a star in which water can exist in the liquid state. The first author of the study, Dr. Paul Rimmer, who is a Postdoctoral Researcher with a Joint Affiliation at the MRCLMB and the Cavendish Laboratory of the Cambridge University talked about that in the following words:

This work allows us to narrow down the best places to search for life. It brings us just a little bit closer to addressing the question of whether we are alone in the universe.”

In 2015, the team of Sutherland published a paper which declared ‘cyanide’ as a vital raw material for the origin of life. According to that paper, meteor strikes into the young Earth resulted in a reaction involving Carbon (from a meteorite) and Nitrogen (from the atmosphere) which led to the development of ‘Hydrogen Cyanide’. This deadly poison interacted with other elements, present on the surface, to generate a range of chemicals which, in turn, produced the building blocks of RNA. The UV light from the sun provided the essential conditions for these reactions. The researchers of Sutherland’s group recreated these chemical reactions under UV lamps and got all the basic components of living cells including amino acids and lipids. Rimmer acknowledged their efforts and said,

I came across these earlier experiments, and as an astronomer, my first question is always what kind of light are you using, which as chemists they hadn’t really thought about. I started out measuring the number of photons emitted by their lamps, and then realized that comparing this light to the light of different stars was a straightforward next step.”

The next thing that the researchers did was to observe the results of a series of experiments, involving Hydrogen Sulphite ions and Hydrogen Cyanide, in UV light as well as darkness. These results proved that UV light is essential for the formation of building blocks of life as the experiments performed in darkness yielded an inert compound which could not be used to produce the necessary components. Once this was done, light chemistry and dark chemistry were compared with respect to the UV light of different stars to determine the range of activation.

They observed that the stars having temperatures similar to our sun offer enough light to assist the formation of building blocks of life on the surface of their planets. They concluded that the planets having liquid water on their surfaces and sufficient light to trigger this chemistry lies in a region called the ‘Abiogenesis Zone’. There are quite a lot of Exoplanets in this list but Kepler 452b is a popular one among them. In spite of their findings, Rimmer clarified that life could develop on another planet in a completely different way. He mentioned that by saying,

I’m not sure how contingent life is, but given that we only have one example so far, it makes sense to look for places that are most like us. There’s an important distinction between what is necessary and what is sufficient. The building blocks are necessary, but they may not be sufficient: it’s possible you could mix them for billions of years and nothing happens. But you want to at least look at the places where the necessary things exist.”

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