If you were to hop on a ship traveling at the speed of light and head out into the galaxy for 40 years, you might come across a cool, red star circled by seven worlds.
Some of those seven Earth-sized planets orbiting TRAPPIST-1 may represent our best chance for finding life of some kind outside of our solar system.
And now, the Hubble Space Telescope is starting to nail down just how much water these worlds may hold. This is a particularly important measurement because nearly every place on Earth with water also harbors life.
Data gathered by the Hubble supports the idea that the two inner-most planets likely lost a lot of water to space due to ultraviolet radiation from TRAPPIST-1.
“Ultraviolet radiation is an important factor in the atmospheric evolution of planets,” Vincent Bourrier, one of the scientists who made this discovery, said in a statement.
“As in our own atmosphere, where ultraviolet sunlight breaks molecules apart, ultraviolet starlight can break water vapour in the atmospheres of exoplanets into hydrogen and oxygen.”
According to the Hubble observations, it’s possible that the innermost worlds could have dumped more than 20 times the volume of Earth’s oceans into space over the course of the last 8 billion years.
That said, the outer planets may still harbor plenty of water that hasn’t been lost to space.
These outer worlds are intriguing to scientists because they are in the so-called “habitable zone” of their dim star — meaning that liquid water might be stable on the surfaces of these far-off planets.
That said, it takes more than water to make a planet habitable. We still aren’t sure what kind of atmosphere — if any — surrounds the distant worlds, and it’s unclear if red dwarf stars like TRAPPIST-1 are conducive to hosting habitable planets. These types of stars might have a nasty flare problem that could vaporize any burgeoning life.
This research is also far from conclusive. Researchers need more powerful tools in space in order to tell exactly what’s going on with these planets.
“While our results suggest that the outer planets are the best candidates to search for water with the upcoming James Webb Space Telescope, they also highlight the need for theoretical studies and complementary observations at all wavelengths to determine the nature of the TRAPPIST-1 planets and their potential habitability,” Bourrier said.