Exoplanets with water has been found in Kepler system

Two planets orbiting a star other than the sun are probably about half water. This would mean that they contain more water than the Earth, scientists conclude in new research.

These are the planets Kepler-138 c and Kepler-138 d. they are about three times the size of the Earth and weigh twice as much. The planets orbit the star Kepler-138, located about 218 light years from Earth. The Galaxy was discovered in 2014 and has now been studied with the Hubble and Spitzer space telescopes. The research was published Thursday in the scientific journal Nature Astronomy.

The scientists did not see the water itself. The planets are too far away. Measurements by the researchers show that they mainly consist of a substance that is lighter than rocks, but heavier than gases such as hydrogen or helium.

The Earth is rocky, but gas giants like Jupiter consist mainly of gas. Water is then the most likely possibility in between, the researchers think. “This is the best evidence for water planets to date. Astronomers have long thought that this type of planet should exist.”

If there is indeed a lot of water on the two planets, that does not mean that they look like Earth. Thus, they do not have to have oceans, waterfalls and precipitation, the scientists emphasize.

It is also not certain if life is possible there. “The temperature in the atmosphere of Kepler-138 d is probably above the boiling point of water. The planet probably has a thick, dense atmosphere of steam. Under it, water could be under high pressure, perhaps between liquid and gaseous.”