In a major breakthrough, scientists have found water on a planet outside our solar system, where temperatures might also be just right to sustain life.

Researchers found water vapor in the atmosphere around K2-18b, a so-called “super-Earth,” located 110 light-years away in the constellation Leo, according to two studies published this week.

It’s not the first planet outside our solar system with water detected in its atmosphere — but it is the first with the temperature range that would make it livable.

“This represents the biggest step yet taken toward our ultimate goal of finding life on other planets, of proving that we are not alone,” said Bjorn Benneke of the University of Montreal, the lead astronomer for one of the studies.

Still, scientists warned that K2-18b isn’t “Earth 2.0” — its atmosphere and surface are different than ours.

It’s also closer to its star than the Earth is to the sun — so it has shorter years, because it completes its orbit in 33 days instead of 365.

“This is definitely not a second Earth,” stressed Angelos Tsiaras, the lead author of the University College London study published Wednesday.

“The only question that we’re trying to ask here, and we’re pushing forward, is the question of habitability,” Tsiaras said, adding that examining the planet further could also help answer the question: “Is the Earth unique?”

The planet, which is twice the size of earth and has eight times the mass, was discovered in 2015 by NASA’s Kepler space telescope.

Researchers for both studies used data collected by the Hubble Space Telescope in 2016 and 2017 to analyze the planet’s atmosphere.

Further observation is necessary to confirm that it is capable of sustaining life and to measure how much water is actually on the planet.

“We are looking forward to the next generation of telescopes and go even further,” Tsiaras said.

With Post wires