Earth-Like Planet Discovered Orbiting Our Closest Neighboring Star

It was cool last year when scientists discovered an Earth-sized planet orbiting a Sun-like star. But a discovery announced today is even bigger: Astronomers have confirmed the existence of an exoplanet that's close to the size of Earth orbiting Proxima Centauri, the closest star to us besides our Sun.

Scientists at the European Southern Observatory in Chile and Queen Mary University in London announced today in Nature that they have located the planet orbiting Proxima Centauri. Excitingly, the planet is the right distance from the star to fulfill the conditions necessary for liquid water to exist on its surface--essential for a planet to support life.

This is an extraordinarily significant discovery due to the fact that Proxima Centauri really isn't that far from our own solar system. As astronomer David Kipping put it, "If you tried to pick the type of planet you'd most want around the type of star you'd most want, it would be this. It's thrilling."

Proxima Centauri is 1.3 parsecs away from Earth, equivalent to 4.24 light years or 25 trillion miles. Obviously, this is still a prohibitive distance from Earth at the moment. However, projects like the Breakthrough Starshot Initiative plan on building spacecraft that use unconventional means of propulsion to cover that distance more quickly. Breakthrough Starshot, for instance, proposes sending a fleet of spacecraft the size of mobile phones to Proxima Centauri. Using lasers to propel these small craft, theoretically they could cover the 4.24 light years in about 20 years.

This solar system is pretty different from ours, however. Named Proxima B, the planet sits about 4.6 million miles from the star--much closer than Earth, which orbits about 90 million miles from the Sun. However, Proxima Centauri is a red dwarf, meaning that it's dimmer, smaller, and cooler than the Sun. As a result, even though it's much closer to the star, Proxima B is within the habitable zone of the Proxima Centauri solar system.

You can read more about the discovery in the full article, published in Nature. Although it's unlikely that we'll see any revelations about extraterrestrial life on this planet anytime soon, scientists are hopeful that they'll be able to learn more about the composition of Proxima B in the coming months.