Located at about 4.2 light years from Earth, Proxima Centauri is the star closest to our Solar System. It’ll very likely be mankind’s first interstellar voyage, especially if and when our Sun decides to heat up and render our planet a scorching wasteland.
We have at least 1 billion years to go until that happens, but, as you may have already noticed, scientists are already searching high and wide for planets similar to our Earth. These aren’t just potential havens for a fugitive human race, but rather nests that could harbor the thing that we search for the most in our astronomical observations: alien life.
In August 2016, scientists from the European Southern Observatory announced the discovery of Proxima b, a planet estimated to be Earth-like orbiting Proxima Centauri. Proxima B’s mass is about 1.3 times the mass of Earth, orbiting its star much more closely. In fact, it’s scary-close to the star, ten times close than Mercury is to the Sun.
But Proxima Centaury is a red dwarf, making our Sun a thousand times more powerful and dangerous. Therefore, Proxima B’s location is within the star’s habitable zone. Since its discovery is quite recent, it’s way too early to assume whether the humans could step on it without spacesuits or if the planet could host extraterrestrial life. But scientists are ever optimistic.
Researchers from the Marseille University in France have conducted simulations in order to better understand the structure of Proxima B. So far, they have approximated the Proxima B’s radius being between 0.94 and 1.4 times the Earth’s own radius.
While it may seem like a pretty accurate approximation to us, the room between those two numbers tell stories of different planets. Should Proxima B have the 0.94 times the radius of Earth, then it would make it a rocky planet, with a dense metallic core two thirds of its mass. If the planet should have liquid water on its surface, it could amount to 0.05% of its mass.
However, if the radius is around 1.4 times the one of Earth, then we could be looking at a planet that’s half rock center, half planetary ocean.
“In this case, Proxima b would be covered by a single, liquid ocean 200 km [124 miles] deep” noted the French researchers.
The study may give us interesting theoretical data about the planet’s mass and composition, but it doesn’t determine anything about the planet’s atmosphere, which could be like our own, or toxic, or completely missing. Surely, it’s way too early to call Proxima B a possible Earth 2.
Image source: Wikipedia