Exoplanets are planets that lie beyond our own solar system and revolve around other stars many light years away. In the past two decades, thousands have been discovered, most of them with NASA’s Kepler Space Telescope. Many of these planets take the namesake of this telescope – the Kepler-10b was one of the first confirmed terrestrial planets to be discovered outside of our solar system. It is incredibly close to its star the Kepler 10. The discovery of this planet excited scientists as it was the first confirmation of an exoplanet.

Geoff Marcy, a pioneering scientist in exoplanets declared the discovery: "as among the most profound scientific discoveries in human history... it is a bridge between the gas giant planets we've been finding and the earth itself.”

NASA's Kepler mission has already identified more than 5,000 potential exoplanets – with the discoveries expected to continue to grow over time.

These many newly discovered worlds come in a variety of material and orbits. Some are gargantuan gas worlds that dwarf Jupiter. Others, rocky and icy barely skidding past their roaring suns. NASA and other space agencies are interested in discovering a variety of planets, but one such kind has also sparked their interest – planets within the habitable zone where liquid water oceans could be formed. The boundaries of what’s habitable and what’s even possible in the universe seem to change every day. Strange compositions we thought impossible are being discovered all the time and with an average estimate of 1 trillion planets in just our galaxy alone, we haven’t even begun to scratch the surface.

These 10 exoplanets are indicative of this novelty.


HD 209458b: Osiris

This planet boasts a number of first discoveries. Scientists have found that it is the only planet currently found outside of the solar system to have detectable oxygen and carbon in its atmosphere. Its parent star is 150 light years from Earth in the Pegasus constellation. Named after the Egyptian god who lost part of his body, Osiris revolves around its sun a mere 4 million miles away.

The scorched planet is evaporating at such a fast rate that scientists have begun to create a new classification of exoplanets called chthonian planets. This nomenclature comes from the infernal Greek deities and H.P. Lovecraft’s subsequent usage for his space monsters. It is most likely a dead core of a completely evaporated gas planet.


Kepler-16b: Tatooine

Astronomer’s research once posited about the possibility of a circumbinary planet – that is, a planet that circles around two stars. In an homage to Luke Skywalker’s home planet in Star Wars, Kepler-16b is nicknamed Tatooine. Whereas Skywalker’s homeworld was habitable, this planet is cold, gaseous and most likely cannot harbor life.

It is 200 light years away from earth. The discovery of a circumbinary planet was hinted at and then confirmed with the observation of brightness of the dual star system being dimmed by a planet’s transit in front of it. While being in the habitable zone is ruled out for this planet, Kepler's principal investigator William Borucki on the importance of this discovery stated:

"This discovery confirms a new class of planetary systems that could harbor life… Given that most stars in our galaxy are part of a binary system, this means the opportunities for life are much broader than if planets form only around single stars. This milestone discovery confirms a theory that scientists have had for decades but could not prove until now."


Kepler-22b: New Earth

One of the most promising and early findings from Kepler is the Kepler 22b. 600 light years away from earth it’s twice the size of Earth and should have temperatures around 72 degrees Fahrenheit. This planet is considered a “super-Earth” and is within the habitable zone of its star. Its star is within the Lyra and Cygnus constellations and shines 25% less bright than our sun.

Scientists think that the planet may have a rocky core and be covered in an ocean like Neptune. But life on the planet isn’t out of the question yet. Kepler deputy science chief stated that “It’s not beyond the realm of possibility that life could exist in such an ocean.”


PSR B1620-26 b: Methuselah

One of the oldest planets in the known universe so far, Methuselah is 2.5 times the mass of Jupiter. It’s also another planet that orbits two stars. At 12.7 billion years ago, this exoplanet tops the aging scales. Interestingly enough, the two stars that it orbits are both burnt out dead stars. It is 12,400 light years away in the constellation of Scorpius.

At first, scientists didn’t know whether to classify it as a brown dwarf or a planet. Since it was created some 1 billion years after the big bang, astronomers have concluded that planets are not a rare phenomenon and ou early universe was probably teeming with them everywhere.