The closest exoplanet to Earth, exoplanet Proxima B is though to meet the necessary conditions to support life as we know it, according to a new study.
Located no more than 4.2 light-years away from us, the alien world has long been thought to meet the necessary conditions to support life as we know it. But recent studies suggested against it, and that despite our best hopes the climate of Proxima B was simply too harsh to support life. Previous studies have suggested that because of strong solar storms, there were little chances for Proxima B to harbor life.
However, a new study makes a case pointing to the fact that this may not be so.
This is according to a set of computer simulations by Anthony Del Genio, a recently retired planetary climate scientist from NASA’s Goddard Institute for Space Studies, who during his career simulated the climates of Earth and other planets in our solar system, helping experts understand our cosmic neighborhood.
Del Genio says that “clouds and oceans play a fundamental role in the habitability of the alien world.”
Del Genio and his team updated a terrestrial climate model first developed in the 1970s to create a planetary simulator called ROCKE-3D. Whether or not Proxima b has an atmosphere is an open question that we hope will be answered by future telescopes.
Del Genio’s team assumed it does have one.
With each simulation, Del Genio’s team varied the types and amounts of greenhouse gases in Proxima B’s atmosphere.
They also changed the depth, size, and salinity of the alien world’s oceans and adjusted the proportion of land to water to see how these adjustments would influence the planet’s climate.
Computer simulations like ROCKE-3D start only with basic information about an exoplanet: its size, mass, and distance from its star.
Scientists can infer these details by observing the light of a star dim when a planet crosses in front of it, or by measuring the gravitational pull of a star as a planet orbits it.
The details are crucial in the equations that comprise up to one million lines of computer code needed to build the most sophisticated climate models.
The code instructs a computer like NASA’s Discover supercomputer to use established rules of nature to simulate global climate systems.
Among many other factors, climate models consider how clouds and oceans circulate and interact and how a sun’s radiation interacts with the atmosphere and surface of a planet.
When Del Genio’s team ran ROCKE-3D on the Discover supercomputer, they saw that the hypothetical clouds of Proxima b acted like a massive umbrella by deflecting solar radiation. Proxima B is 20 times closer to its star than Earth is to the Sun.
The clouds of Proxima B could reduce the temperature on the sun-facing side of the exoplanet from too hot to warm. Additional studies of the planet have shown that Proxima b could be home to clouds so massive that they would erase the entire sky if viewed from the surface.
“If a planet is gravitationally locked and rotating slowly on its axis a circle of clouds forms in front of the star, always pointing towards it. This is due to a force known as the Coriolis effect, which causes convection at the location where the star is heating the atmosphere,” explained Ravi Kopparapu, a NASA Goddard planetary scientist.
“Our modeling shows that Proxima b could look like this.”
In addition to making the Proxima b dayside more temperate than expected, a combination of atmosphere and ocean circulation would move warm air and water around the planet, thus transporting heat to the cold side.
“So you not only keep the atmosphere on the night side from freezing out, you create parts on the night side that actually maintain liquid water on the surface, even though those parts see no light,” Del Genio revealed.
The exoplanet Proxima B is believed to have an orbital period of approximately 11.2 Earth days and has an estimated mass of at least 1.3 times that of the Earth.
The exoplanet was found in 2016 by the European Southern Observatory.