The rocky planet which could be a “scaled up version of Earth”, orbits its star in the habitable zone meaning it may be covered in liquid water and be teeming with life.
The planet’s rocky make up and distance from its star, making it a key candidate for life as we know it, were discovered by researchers at the University of Texas and the University of Montreal.
Analysis of the planets makeup, made by measuring the effect it has on its star’s velocity, revealed it is likely to have a rocky composition and a gassy atmosphere just like our Earth, but bigger.
Using the European Southern Observatory telescope experts were able to observe the composition of K2-18b and also discovered its sister planet K2-18c, although its orbit means it is less likely to support life.
Ryan Cloutier, from the University of Montreal, said: “Being able to measure the mass and density of K2-18b was tremendous, but to discover a new exoplanet was lucky and equally exciting.”
The planet orbits a star 111 light years away from earth in the Leo constellation.
It has excited researchers already making plans to study it further as humans continue our search for first contact.
K2-18b presents a unique opportunity for investigation when NASA’s James Webb Space Telescope is launched in 2019.
Researcher Professor René Doyon said: “There’s a lot of demand to use this telescope, so you have to be meticulous in choosing which exoplanets to look at.
“K2-18b is now one of the best targets for atmospheric study, it’s going to the near top of the list.”
James Webb Space Telescope is designed to observe some of the most distant events and object in the universe in the greatest clarity.
The telescope will be able to view objects beyond the range of our current space-based instruments, including Hubble.
News of K2-18b hospitable environment comes in stark contrast to NASA’s discovery of a giant “death planet” with a poisonous atmosphere which “defies expectations”.
The planet named Wasp-18b has a toxic atmosphere making it impossible for it to support life with an upper atmosphere swamped by toxic carbon monoxide.
NASA’s Kyle Sheppard, who led the study, said: “The composition of WASP-18b defies all expectations.
“We don’t know of any other extrasolar planet where carbon monoxide so completely dominates the upper atmosphere.”
The planet is unique among those observed by humans with NASA previously believing such a world could not exist.
The unexpected composition of the planet means it could redefine the way scientists think gas giants form.
Wasp-18b’s extremely close orbit to its star and lack of an Ozone adds to the hostile environment of the planet which is 10 times larger than our solar system’s biggest, Jupiter.