Planets that contain liquid water, a key ingredient for life, may be 100 times more common than previously thought. This is evidenced by the results of a study presented at the Goldschmidt conference in Lyon, France, writes The Vice.

This means that for every star system in our Galaxy, there could be an average of one planet with liquid water, which greatly expands the possibilities for life on planets.

Scientists have demonstrated that hidden underground reservoirs can form on planets orbiting red dwarf stars, stars that are much smaller than the Sun. The discovery has major implications for the search for extraterrestrial life, as red dwarfs, also known as M dwarfs, are the most common class of stars.

Water is so essential to life on Earth that scientists consider it the most valuable compound to look for when searching for aliens on other worlds. Although Earth is the only planet in the Solar System that has water oceans on its surface, several of its nearby celestial bodies have subsurface oceans beneath their icy shells, including Jupiter’s moon Europa and Saturn’s moon Enceladus.

Rutgers University planetary scientist Lujendra Ojha presented at the conference evidence for the existence of geothermal heat on many cold “exo-Earths,” that is, Earth-like planets in other star systems. These subglacial oceans in red dwarf systems “might resemble the subsurface conditions found on Europa” and “may provide habitable conditions for an extended period,”

It was previously reported that a third of the most common planets around small stars throughout the galaxy may be in conditions that allow liquid water to hold and possibly support life. We are potentially talking about hundreds of millions of planets.