There may be many more planets capable of supporting extraterrestrial life than previously thought, a new study suggests.
For years, the scientific search for life beyond Earth has focused on the so-called “habitable zone” or “Goldilocks zone,” an orbital strip where it is neither too hot nor too cold to allow the existence of liquid water. This condition is considered key for a planet to be potentially habitable.
However, many of the exoplanets discovered so far do not meet those criteria. As a result, researchers have assumed that a large portion of these worlds would likely be inhospitable to life.
Now, however, new research suggests that those criteria may have been too restrictive. There may be other worlds capable of preserving liquid water that we have so far overlooked.
Researchers believe that, on tidally coupled planets – that is, where one hemisphere always faces its star and the other remains in darkness – heat could be distributed sufficiently to allow the presence of liquid water on its surface. To reach this conclusion, they used a climate model that simulates how the atmosphere would work on a planet with these characteristics.
According to the study, heat coming from the day side of the planet could shift to the night side and keep temperatures above freezing. This suggests that the number of potentially habitable environments in the universe would be much larger than previously thought, and could even include some of the planets recently observed by the space telescope. James Webb from NASA, which show signs of water vapor and other volatile gases. These worlds would actually be within the appropriate range to conserve water on their surface.
The researchers also propose that even planets located at the opposite end, too far from their star to have liquid water, could be habitable. In those cases, water could be stored under thick layers of ice, suggesting there could be even more worlds with the potential to host extraterrestrial life.
The results of the study were presented in a new article titled “Exoplanets beyond the Conservative Habitable Zone. I. Habitability”, published in the journal The Astrophysical Journal.