The most Earth-like planet yet found has just been discovered by the Kepler space probe. The newly discovered exoplanet is actually about 1.5 times bigger than Earth, so it’s known as a ‘super-Earth’. The planet, KOI (Kepler Object of Interest) 172.02, is following an orbit that is well within the habitable zone of a star that is rather similar to our Sun. This leaves open the possibility that the planet could feature liquid water and potentially oceans on its surface.
KOI 172.02 orbits at a distance of around 0.75 astronomical units from its star, meaning that it is about 3/4 the distance from its star that the Earth is from the sun. Specifically, this means that KOI-172.02 orbits around 70 million miles from its star rather than the 93 million miles that the Earth orbits from the Sun. And as a result completes an orbit around its star in 242 Earth days.
“Launched in 2009, the Kepler space telescope orbits the sun every 371 days. As it travels, Kepler keeps itself pointed at a single patch of sky. Sensors monitor the brightness of 150,000 stars simultaneously, looking for telltale drops in intensity that could indicate orbiting planets.”
“At the heart of the telescope is an array of 42 camera sensors specifically designed to detect planets passing in front of their stars”
“Kepler’s planet search is conducted in a narrow wedge-shaped volume of space that stretches out ahead of us as we orbit the galaxy. Stars in the search volume are therefore at about the same distance from the center of the galaxy as the Earth.”
Researchers from NASA note that the planet would be a prime candidate to explore in the search for extraterrestrial life. Though other, more strange seeming planets, such as the recently discovered rogue planet that is only 100 light years away, could also potentially host life.
Some more information on Earth-like planets:
An Earth analog, or Earth-like planet, is a theorezied type of exoplanet, or moon, that features conditions very similar to the Earth.
“The possibility is of particular interest to humans as it is easily inferred that the more similar a planet is to Earth, the more likely it is of sustaining Earth-like complex extraterrestrial life and, more importantly, civilization. As such it has long been speculated and the subject expressed in science, philosophy, science fiction and popular culture. Advocates of space colonization have long sought an Earth Analog as a ‘second home’ while advocates for space and survival would regard such a planet as a potential ‘new home’.”
“Before the scientific search for and study of extrasolar planets, the possibility was argued through philosophy and science fiction. The Mediocrity principle suggests that planets like the Earth should be common in an infinite universe, while the Rare Earth hypothesis suggests that they are extremely rare. Philosophers have pointed out that the size of the universe is such that a near identical planet must exist somewhere, such theories include the philosophy of Multiverse and the Twin Earth thought experiment.”
“Some scientific theories speculate that Earth analogs may have existed in our Solar System in the past. In the future, technology may be used by humans to artificially produce an Earth analog. In theory, terraforming, virtual reality or simulated reality could potentially create such a world. Multiverse theory suggests that an Earth analog could exist in another universe or even be another version of the Earth itself in a parallel universe.”
“Technological advances in extrasolar planet detection are rapidly refining the probabilities of a real discovery, not just in this universe, but in the present Milky Way galaxy, though distribution and attributes are still very much unknown. Different studies on the frequency of Earth-like planets in the Milky Way have resulted in estimation varying from one (ie the Earth) to hundreds of billions. Current calculations tend to indicate that they may be relatively common in the universe.”
“The more recent serious scientific findings have greatly influenced the scope of the fields of astrobiology, models of planetary habitability and Search for Extraterrestrial Intelligence. NASA and the SETI Institute have proposed categorising the increasing number of Earth-like planets found using a measure called the Earth Similarity Index based on mass, radius and temperature. According to this measure, the planet currently thought to be most similar to Earth is Gliese 667C c.”
Image Credits: NASA