Recently, Cambridge University scientists discovered the best candidate so far for extraterrestrial life on an ocean world, 120 light years away. Using NASA’s James Webb Space Telescope, they saw biosignatures in the atmosphere, dimethyl sulphide and dimethyl disulphide. We have these compounds on Earth too, because our bacteria and marine phytoplankton both produce them. Seeing these signs of life on K2-18b, a Neptune-like world that orbits the red dwarf star K2-18, is a solid indication that we may not be alone.
K2-18b is a bit unusual as a planet in the “habitable zone,” where the temperature is just right for water to exist and support life as we know it. Scientists estimate that its climate actually swings from -100 degrees to 116 degrees Fahrenheit. However, it likely has a warm ocean that could be full of simple, algae-like life, Cambridge astrophysics and exoplanetary science professor Nikku Madhusudhan, Ph.D., told The New York Times. He’s an author on a study of K2-18b that was published in April in the Astrophysical Journal Letters.
According to astronomers’ estimates, K2-18b is still only one of potentially 300 million worlds in the Milky Way that could exist in a habitable zone. Life on a planet other than Earth still needs to be confirmed. But scientists are now studying nearly 6,000 known exoplanets, planets outside our solar system, that could support life. The most intriguing of these, and the ones researchers are focusing on, are worlds that have warmer climates than Earth, because any extraterrestrials there may have a leg up in their development.
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