Scientists believe some planets in the universe could have warmer climates, more water and better conditions for life than Earth. They call these potential worlds “superhabitable” planets, although none has yet been confirmed to exist.
These planets could be 20 to 30 percent larger in diameter than Earth and have roughly twice its mass. Their stronger gravity could help them retain thicker atmospheres, while larger iron cores could generate powerful magnetic fields to shield them from harmful radiation.
Extensive shallow seas, lakes and islands could also create favourable conditions for biodiversity. Earth itself has rich ecosystems in environments with similar features.
Researchers are particularly interested in planets orbiting orange K-dwarf stars. Smaller and cooler than the Sun, these stars burn through their fuel more slowly and may remain stable for tens of billions of years. This could give life on nearby planets more time to evolve.
In a Berlin laboratory, astrobiologist Eva Villović has grown garden cress under light designed to simulate radiation from such stars. Compared with plants grown under artificial sunlight, the cress grew faster and taller. The findings suggest that photosynthesis could function effectively under these conditions.
In 2014, astronomers René Heller and John Armstrong introduced the concept of superhabitable worlds. They argued that the search for life should extend beyond planets that simply resemble Earth.
The Sun is gradually becoming brighter. According to researchers, Earth could become too hot to support complex life, including plants and animals, in about 500 million years.
Scientists are looking to the European Space Agency's PLATO mission, scheduled for launch in 2027, to help identify potentially habitable planets. Telescopes, including the James Webb Space Telescope, could later be used to search their atmospheres for possible signs of life.
However, favourable conditions do not necessarily mean that life exists. Earth remains the only planet on which life has been confirmed so far.