Can This Exoplanet Be The New Earth?


    What will happen to us if the Earth just ceases to exist? What if life as we know it has no habitable environment to sustain? Where would we go then? Although the possibility of the extinction of Earth seems to be converging at a comfortably distant part of the future, a life away from our home planet is an intriguing but rather worrisome thought.

    Going by the timeless saying “Better safe than sorry”, researchers have been looking for alternative planets which could potentially replace ours should the dreaded day arise. After years of research, we seem to have struck luck with the discovery of Proxima b, a nearby exoplanet orbiting within the habitable zone of a star just 4.2 light-years from Earth. 

    Since its discovery, questions about the conditions at the surface of Proxima b have been circulating; the planet’s mass is just about 1.3 times that of Earth’s, and the red dwarf star it circles is similar in age to our sun.

    After further study of Proxima b, the chances of the planet supporting life appeared to be rather dim but new study has revealed some information which seems to be a ray of hope in the quest for a home planet. The study has once again raised the possibility that Proxima b could support life, suggesting that under the right conditions, the exoplanet could sustain liquid water.

    ‘The major message from our simulations is that there’s a decent chance that the planet would be habitable,’ said Anthony Del Genio, a planetary scientist at the NASA Goddard Institute for Space Studies. In the study published this month in the journal Astrobiology, the researchers ran what are said to be the first climate simulations of Proxima b with a dynamic ocean.

    The planet is thought to be tidally locked with its star, Proxima Centauri, meaning it would have a permanent ‘dayside’ and ‘nightside.’ This implies that one side of the planet would experience frozen water conditions while the other side doesn’t necessarily have to be frozen.

    ‘Climate models with static oceans suggest that Proxima b could harbor a small dayside surface ocean despite its weak instellation,’ the researchers explain in the new study. The simulations showed that ‘with a dynamic ocean, a hypothetical ocean-covered Proxima Centauri b with an atmosphere similar to modern Earth’s can have a habitable climate with a broad region of open ocean, extending to the nightside at low latitudes.’

    Proxima b orbits the red dwarf Proxima Centauri, which is part of a triple system including the binary pair  Alpha Centauri A and B. An artist’s impression is shown.

    The researchers also experimented with different salinity levels and greenhouse gas conditions which helped in determining the available water region. After playing around with a few dozen simulations, scientists concluded that Proxima b almost always had some sort of a liquid ocean.

    ‘We find that an ocean-covered Proxima b could have a much broader area of surface liquid water but at much colder temperatures than previously suggested, due to ocean heat transport and/or depression of the freezing point by salinity,’ the researchers wrote. The conditions of the exoplanet are still in debate however, irrespective of the results, we know we are headed in the right direction!

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