A new study suggests that our galaxy may host 100 times more habitable worlds than previously estimated, reports vice.com.
The search for life beyond Earth has focused on finding planets with liquid water, which is essential for life as we know it.
However, liquid water may not only exist on the surface of planets, but also under thick layers of ice, as seen on some of the moons in our solar system, such as Europa and Enceladus.
The researchers, who presented their findings at the Goldschmidt geochemistry conference in Lyon, France this week, argue that such subsurface oceans could be common around red dwarf stars, which are the most abundant type of stars in the galaxy.
They claim that the heat from the rocky cores of these planets could melt the ice and create habitable environments.
“We have found many Earth-like exoplanets orbiting M dwarfs, which are red dwarf stars,” planetary scientist Lujendra Ojha told Motherboard.
“We wanted to investigate if basal melting, which is one of the possible ways of producing liquid water on our solar system’s planets billions of years ago, could also occur on other planets.”
If their results are confirmed, then it could imply that there are many more places where life could potentially emerge and evolve than we thought before.
“The habitability of M dwarfs is a very interesting and a very debated topic,” Ojha said.
“What’s interesting, and I think noteworthy, about the idea of basal melting and subsurface oceans is that the star could be the biggest bully in that galaxy and it doesn’t matter. Underneath a couple of meters of ice, if there is water and if there is some sort of primordial life, most of the X-rays, or the solar flares that maybe sporadic, are not going to notably affect these deep biospheres compared to if the life or biosphere were on the surface.”
“Deep, deep within the ice, it provides a refuge, so I think it’s interesting that basal melting not only provides an alternative way of creating this habitable environment, but it’s very much more protected than if there was any like the surface,” he added.
“One of the most important things that we will learn from those missions is the chemistry of the water, what the water is like, how much heat do you need for this water to be sustainable to life, and potentially looking for astrobiological signals,” Ojha said. “I think that would help us in understanding the habitability of ocean worlds.”
“One potential way for us to look at the possibility of basal melting on these other bodies is to potentially see signatures of plumes of water coming out similar to what we see in Enceladus and Europa, but we will need a slightly better adaptive optics for our telescope, so that’s also slightly in the future,” he concluded.