{"id":243739,"date":"2023-09-13T07:53:43","date_gmt":"2023-09-13T05:53:43","guid":{"rendered":"https:\/\/osr.org\/?p=243739"},"modified":"2023-09-18T09:21:48","modified_gmt":"2023-09-18T07:21:48","slug":"have-we-just-found-signs-of-life-on-exoplanet-k2-18b","status":"publish","type":"post","link":"https:\/\/osr.org\/en-uk\/blog\/news-en-uk\/have-we-just-found-signs-of-life-on-exoplanet-k2-18b\/","title":{"rendered":"Have We Just Found Signs of Life on Exoplanet K2-18b?"},"content":{"rendered":"

Imagine, if you will, a planet nearly nine times the size of our dear old Earth. It’s a place so far removed from our cosy corner of the universe that it’s been given the rather dry moniker of K2-18b. Doesn’t quite have the ring of ‘Earth’, does it? Nevertheless, this distant world may be harbouring something truly extraordinary: potential signs of life.<\/p>\n

What Is K2-18b?<\/span><\/h2>\n
\"K2-18b\"

Credits: Illustration: NASA, CSA, ESA, J. Olmsted (STScI), Science: N. Madhusudhan (Cambridge University)<\/p><\/figure> Credits: Illustration: NASA, CSA, ESA, J. Olmsted (STScI), Science: N. Madhusudhan (Cambridge University)<\/p><\/div>\n

K2-18b<\/a> is an exoplanet located 124 light-years away from Earth. Discovered in 2015, this intriguing exoplanet orbits a red dwarf star named K2-18. It occupies a position within the star’s habitable zone, a heavenly sweet spot where conditions might be right for liquid water and life.
\nFirst spotted by NASA’s Kepler space telescope, the planet is over eight times the mass of Earth and is believed to be a water world, with estimates suggesting that up to 50% of its mass could be composed of water. This would be quite a departure from our home, where water makes up a somewhat more modest 0.02% of our planet’s total mass. But here’s where things get exciting. In 2019, an international team of astronomers detected water vapour in the planet’s atmosphere using the Hubble Space Telescope – the first time we’ve found water vapour on an exoplanet that\u2019s orbiting in its star’s habitable zone. Indeed, the combination of water vapour and hydrogen discovered on K2-18b led to a new classification of exoplanet: Hycean planets.<\/p>\n

What Are Hycean Planets?<\/span><\/h2>\n

\"Hycean
\nHycean planets<\/a>, a portmanteau of “hydrogen” and “ocean”, represent a category of exoplanets that could <\/em>potentially harbour life. These celestial bodies are typically larger than Earth but smaller than Neptune and are enveloped in a thick, hydrogen-rich atmosphere, possibly concealing a vast ocean beneath.
\nAstronomers initially thought that Hycean worlds were subject to relatively high atmospheric temperatures of up to 200 degrees Celsius, making it difficult to sustain life. However, evidence from K2-18b suggests that some Hycean planets may be able to maintain lower temperatures due to their thick hydrogen envelope, making them more conducive to habitability.<\/p>\n

Confirmed Methane and Carbon Dioxide on K2-18b<\/span><\/h2>\n
https:\/\/youtu.be\/VpuD6eR6nb4<\/a>