Scientists are exploring whether planets beyond our solar system could offer better conditions for life than Earth, with some researchers suggesting that slightly larger planets orbiting orange-hued stars may be among the most promising places to look for extraterrestrial life.These planets, known as “superhabitable worlds”, could sustain life for longer and support greater biological diversity than Earth, according to a report by The New York Times.The idea centres on super-Earths, planets that are larger than our own, orbiting K-dwarf stars, which are cooler and burn their fuel more slowly than the Sun.Astrobiologist Iva Vilović, who studies how plants respond to different types of light, found that garden cress grew faster and taller under simulated light from a K-dwarf star than under simulated sunlight in a laboratory experiment in Berlin.“K-dwarf light is a very, very interesting light source, and it should be considered, if not prioritized, for any type of search for extraterrestrial life, in my opinion,” NYT quoted Vilović as saying.
What makes these worlds potentially more habitable?
Scientists envision a superhabitable planet as roughly 20% to 30% wider and twice as massive as Earth, with liquid water on its surface. Its stronger gravity could help it retain a thicker atmosphere, potentially supporting a warmer and more stable climate. A larger iron core could also generate a stronger magnetic field, offering greater protection from cosmic radiation.Such planets could have shallower seas and more extensive island chains, creating conditions favourable to diverse ecosystems. On Earth, tropical islands and shallow waters support rich biodiversity. Researchers speculate that similar environments across an entire planet could support a wide variety of alien life.The concept was proposed in a 2014 paper by astronomers René Heller and John Armstrong, who questioned whether Earth should be the benchmark for identifying habitable planets.
Why K-dwarf stars are promising
Unlike the Sun, which is expected to become too hot for complex life on Earth in roughly half a billion years, K-dwarf stars can remain stable for tens of billions of years. This could give life on planets orbiting them much longer to evolve and diversify.K-dwarf systems may also offer an observational advantage. Planets capable of supporting liquid water orbit closer to these stars than they would to stars like the Sun, potentially making them easier for astronomers to study.Scientists have faced challenges studying planets around smaller red stars, known as M-dwarfs, as their intense stellar activity can strip away planetary atmospheres. Researchers hope that planets orbiting K-dwarfs could offer more promising targets for investigating atmospheric conditions that might support life.
How will scientists search for them?
The next step is to identify suitable planets and study their atmospheres for gases that could indicate biological activity.The European Space Agency’s Plato mission, scheduled for launch in 2027, is expected to search for potentially habitable planets, including super-Earths orbiting K-dwarf stars. Further observations could help researchers investigate their atmospheric composition using telescopes such as the James Webb Space Telescope and the Extremely Large Telescope, which is under construction in Chile.A planned Nasa mission, the Habitable Worlds Observatory, could enable more detailed observations in the 2040s.For now, superhabitable worlds remain a scientific hypothesis rather than confirmed havens for alien life. But researchers believe broadening the search beyond Earth-like planets could improve the chances of finding worlds capable of sustaining life.NYT quoted Vilović as saying she believes life is statistically likely to exist somewhere in the universe, particularly on superhabitable planets.
