K2-18b, which is eight times the mass of Earth and about 110 light years away, is currently the only known planet orbiting a star outside the Solar System that could have both water and temperatures that could support life.

The discovery was made by scientists at University College London (UCL) who applied open-source algorithms to data from 2016 and 2017 captured by the ESA/NASA Hubble Space Telescope.

The algorithm in question analysed starlight filtered through K2-18b’s atmosphere. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet’s atmosphere.

The exoplanet was first spotted in 2015 by Nasa’s now defunct Kepler spacecraft, but the data analysis has revealed the new details about its atmosphere.

The UCL team believes that other molecules including nitrogen and methane may be present, but with current observations they remain undetectable. Further studies are required to estimate cloud coverage and the percentage of atmospheric water present.

UCL professor Dr Ingo Waldmann said: “With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets.

“This is not only because super-Earths like K2-18b are the most common planets in our Galaxy, but also because red dwarfs – stars smaller than our Sun – are the most common stars.”

The planet is a lot closer to its star than Earth is to the Sun, meaning it only takes around 33 days to transit.

“It’s the only planet outside our solar system that we know has the correct temperature, an atmosphere and water,” said Dr Angelos Tsiaras.

“Of course, K2-18b is not a second Earth, because it is a planet that is much bigger [and] has a different atmospheric composition. It’s orbiting a completely different star, so it doesn’t look like Earth.

“The search for habitable planets, it’s very exciting, but it’s here to always remind us that this [Earth] is our only home and it’s probably out of the question if we will be able to travel to other planets.”

Although the planet sits in the habitable zone, scientists say that instruments available at present are not able to determine any signs of life.

It will also require many more observations to be sure that it is a habitable planet.

The team hopes that newer technology, such as the James Webb Space Telescope due to launch in March 2021, will be able to unlock more secrets beyond our solar system.

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

Last September, Nasa’s Transiting Exoplanet Survey Satellite (Tess) discovered two distant planets five months after its launch.

K2-18b, which is eight times the mass of Earth and about 110 light years away, is currently the only known planet orbiting a star outside the Solar System that could have both water and temperatures that could support life.

The discovery was made by scientists at University College London (UCL) who applied open-source algorithms to data from 2016 and 2017 captured by the ESA/NASA Hubble Space Telescope.

The algorithm in question analysed starlight filtered through K2-18b’s atmosphere. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet’s atmosphere.

The exoplanet was first spotted in 2015 by Nasa’s now defunct Kepler spacecraft, but the data analysis has revealed the new details about its atmosphere.

The UCL team believes that other molecules including nitrogen and methane may be present, but with current observations they remain undetectable. Further studies are required to estimate cloud coverage and the percentage of atmospheric water present.

UCL professor Dr Ingo Waldmann said: “With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets.

“This is not only because super-Earths like K2-18b are the most common planets in our Galaxy, but also because red dwarfs – stars smaller than our Sun – are the most common stars.”

The planet is a lot closer to its star than Earth is to the Sun, meaning it only takes around 33 days to transit.

“It’s the only planet outside our solar system that we know has the correct temperature, an atmosphere and water,” said Dr Angelos Tsiaras.

“Of course, K2-18b is not a second Earth, because it is a planet that is much bigger [and] has a different atmospheric composition. It’s orbiting a completely different star, so it doesn’t look like Earth.

“The search for habitable planets, it’s very exciting, but it’s here to always remind us that this [Earth] is our only home and it’s probably out of the question if we will be able to travel to other planets.”

Although the planet sits in the habitable zone, scientists say that instruments available at present are not able to determine any signs of life.

It will also require many more observations to be sure that it is a habitable planet.

The team hopes that newer technology, such as the James Webb Space Telescope due to launch in March 2021, will be able to unlock more secrets beyond our solar system.

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

Last September, Nasa’s Transiting Exoplanet Survey Satellite (Tess) discovered two distant planets five months after its launch.