Astronomers have detected water in the atmosphere of a potentially habitable planet -called K2-18b in September 2019. It’s a plausible candidate in the search alien life. In the next ten years, the new space telescopes will be able to find whether this planet’s atmosphere contains gases produced by living organisms.
The scientific journal Nature Astronomy published details about this discovery. Prof. Giovanna Tinetti of University College London described the planet as “mind-blowing.”
“Until now, we haven’t detected water on a planet in the habitable area around a star where the temperature is closely compatible with the presence of life,” said Giovanna.
The habitable zone is around the star where the temperature is sufficiently benign for water to be found in liquid form on the planet’s surface. This discovery is twice bigger than Earth. It is in a planet category called “supper Earth.” Its temperature is optimal enough (between 0 and 40C) to keep the water in a liquid state.
Because of the significant distance (650 million miles) from our planet, it is impossible to send a probe. The only hope is the future telescopes that will be launched in the 2020s. They will be able to discover gases in the atmosphere of the new planet.
Those planets that are beyond our Solar System are called exoplanets. More than 4000 have been detected so far. The first exoplanet was discovered in 1992, emitting electromagnetic radiation. Some of them are large as Jupiter, orbiting close to their stars.
The researchers looked through the planets found by the Hubble space telescope between 2016 and 2017. They could determine that the light filtered through the planets’ atmospheres was subtly altered because of the composition of the atmosphere. Only K2-18b showed molecular signs of water.
“Finding this habitable planet was an exciting experience,” said Dr. Angelo’s Tsiaras, member of the UCL team.
Other astronomers think that this planet could not support life. According to some analysis, a planet with this size and gravity can’t be habitable. Other critics consider the planet as a mini Neptune, and this class of planet is more massive than the super-Earth. Prof Tinetti, however, still believes it’s a habitable planet.
She said to BBC News, ” K2-18b is more likely to be a planet of rocks and ices, and it can not be classified as mini- Neptune. These planets are called ocean planets”.
“We don’t know if the planet has rock or ocean at its surface, but the presence of the water in the atmosphere is an excellent start.”
“The Earth stands out in the Solar System. It has water, oxygen, and ozone. If we find all of them around another planet far away from us, we should be cautious before saying that there is life on that planet. That is the reason why we have to understand hundreds of planets, and we hope that habitable planets will stand out. Then we will be able to make differences between the habitable and the non-habitable planets”, said Tinetti.
Dr. Laura Kreidberg of the Centre for Astrophysics at Harvard University doesn’t agree with this theory. According to her, the pressure and the temperature increase in-depth on this planet. The high temperature and the high pressure do not allow the presence of complex molecules like DNA.
Prof David Charbonneau from Harvard University pointed to the fact that this planet could not support life because its atmosphere was detected.
“If it had a secondary atmosphere similar to ours, it would be fragile, and Hubble could not detect it.”