Watch: 'Will try to find methane next,' says astronomer on water found on exoplanet

In a conversation with WION, Angelos Tsiaras, an astronomer at UCL, shared insights on the presence of water on an Earth-like planet outside our solar system. 

Water vapour was found in the atmosphere of K2-18b, one of the hundreds of "super-Earths" - worlds ranging in size between Earth and Neptune - documented in a growing new field of astronomy devoted to the exploration of so-called exoplanets elsewhere in the Milky Way galaxy.

Here are some excerpts from the interview:

WION: Why is the discovery of water on this exoplanet significant?

Tsiaras: This planet as of now is one of the best candidates to be a habitable place out there in the universe. To find signs of life or a habitable planet we will need much better observations. This will come in the next decades. 

Unless we don't have these big telescopes we cannot say much.

WION: What do we know of this exoplanet, is it gaseous in nature or does it have a surface?

Tsiaras: The planet has a density similar to Mars or Moon. This means that probably, it has a surface. It is definitely not a gas giant. 

WION: How is water found here any different from water on the moons of Jupiter and Saturn?

Tsiaras: Water on icy moons is in the liquid form, it is like an ocean inside an ice cover. Here, we are talking about gaseous water. We don't know if there is liquid water. We know that the planet can support liquid water but we cannot say that for sure. 

WION: What is the next step?

Tsiaras: The next step will be to use the James Webb Space Telescope, it will be able to give us a much better spectrum of the planet. We will try to find methane on the planet as the next step. As we know, on Earth methane is a sign of life. It is produced because life is here. We don't know if life outside in the universe is working in the same way. 

Scientists for the first time have detected water in the atmosphere of an Earth-like planet orbiting a distant star, evidence that a key ingredient for life exists beyond our solar system, according to a study published on Wednesday.