NASA’s Kepler space telescope has found an Earth-like planet orbiting in the habitable zone of a star much like our own. The planet, called Kepler 452b, was revealed today after NASA hinted at a very exciting discovery yesterday.
This discovery is very exciting for astrobiologists and astronomers because it seems to be a very good candidate for a home of extraterrestrial life. Several exoplanets that Kepler has found are potentially habitable but there are some key features about 452b that set it aside from the rest.
First of all, it’s orbiting a sun-like star. Kepler 452, the star it orbits, is in the same class of star as our sun. They are both G type stars. Most of the potentially habitable exoplanets found to date are much smaller pouring out less energy onto their planets. Planets in the habitable zone of small stars tend to be tidally locked so one side is in perpetual darkness while the other is constantly bathed in sunlight. This isn’t good news for life but Kepler 542b is orbiting a sun-like star which is very good news.
Another reason Kepler 542b is an exciting find is that it is inside its star habitable zone. Sometimes dubbed the ‘Goldie-Locks Zone’, this is the area around a star where it is not too hot and not too cold for water to exist on a planet’s surface. Water is essential to life as we know it, so the potential for the presence of water on the surface of this planet is very exciting.
Kepler 542b is very similar in size to Earth being only about 60% larger. This gives NASA scientists very good reason to believe it is a rocky world like Earth. Its diameter is about 20,000 km compared to Earth’s 12,700 km. It’s size means that it could support an atmosphere that is a little bit thicker than Earth’s. It would likely be a bit cloudier on this planet than on Earth. If the atmosphere of this planet is similar in composition to Earths, it could definitely be able to support life.
The orbit of Kepler 542b is 385 days, just 20 more than Earth’s orbit. This suggests it is in a very similar position that Earth is. Kepler 542b and its star are about 6 billion years old so it is a bit older than our solar system. This is more than enough time for life to evolve if it has emerged on this planet.
The only drawback is the distance of this planet to us. It is 1400 light-years away so it may be difficult to investigate with our current technology.
This planet was the highlight in a catalogue of 500 new planets found by Kepler, 12 of which are similar in size to Earth. Nine of these are in the habitable zone of their star so there is more potential for other habitable worlds.
Hopefully in the coming months and years we hear more about this planet as scientists investigate it further.