In the search for exoplanets, among all the “Hot Jupiters” and two-faced hellish domains, scientists hope more than anything to find Earth-like worlds, ones that may hold life. A truly breathtaking new Nature study has dramatically revealed that a second home may exist just over 4 light-years away, in the Alpha Centauri triple star system.
This new world dances around the red dwarf star Proxima Centauri, which is the closest star to our own Sun. Dubbed “Proxima b”, this exoplanet was discovered after painstaking years of analysis of the tiny movements of its host star in response to the gravitational pull of the planet itself. By picking apart these stellar wobbles, estimates of the planet’s mass and physical parameters could be made.
It orbits the star every 11.2 days at an incredibly short distance of 7.5 million kilometers (4.7 million miles). It’s tidally locked, which means that one side of the planet always faces the star, and the other remains in perpetual darkness. The planet, which is equivalent to 1.3 Earth-masses, is likely to be around 5 billion years old, based on the age of the star system it's residing in.
It’s possibly terrestrial, meaning that it has a rocky surface, and based on its temperature, it is possible for liquid water to exist at the surface. As we know from our own pale blue dot, where there is water, there is life. This means that Proxima b is likely to be the nearest possible home to life outside our own Solar System.
After all this time looking into the far reaches of space, we may have a second Earth sitting right next door in our own cosmic backyard. Although it’s too early to definitively state that this world is “Earth-like”, as the presence of an atmosphere and water have yet to be shown, chances aren’t unreasonable for both being present.
“Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us,” lead author Dr Guillem Anglada-Escudé, a senior researcher at Queen Mary University London, said in a statement.
“Many people’s stories and efforts have converged on this discovery. The result is also a tribute to all of them.”
An artist's impression of what the surface of Proxima b may look like. Alpha Centauri A and B can be seen to the top-right of Proxima Centauri. Credit: ESO/M. Kornmesser
Gif in text: Assuming Proxima b has an Earth-like atmosphere, this is what the temperatures would be like on the day-side and night-side. European Southern Observatory via YouTube