Until now, we’ve only heard of one planet harboring life: Planet Earth. But we’ve all asked ourselves if there is a planet like ours somewhere in space. A new study suggests that we should also consider moons as a good place to colonize.
The new study was published in The Astrophysical Journal. Researchers suggest that there are 121 massive exoplanets, each having a moon that could harbor life.
The Kepler space telescope from NASA confirmed that there are 2,000 exoplanets. Researchers modelled how giant planets like Jupiter or Saturn could orbit a star in a region that allows the existence of liquid water on their surface. Out of the 2,000 exoplanets, 121 of them might have only one moon.
What Makes Life on Earth Possible?
We exist on this planet because we’re close to the sun and get energy, we have water, the atmosphere and a magnetic field that acts like a shield against space radiation.
But while we get the energy from our sun, scientists think that exomoons can get the energy from the star and from the giant exoplanet. According to this theory, scientists believe that those exomoons can be “super-habitable.”
Jupiter and Saturn’s moons get their energy from the two planets, so it can happen to other moons of the planets outside our solar system.
The “super-habitable” idea comes from the elliptical orbit of some moons that, as they orbit around the planet, there is a gravitational interaction. This interaction squeezes the moon, known as tidal flexing, and it causes heating. The planet’s magnetism can protect its moons from cosmic radiation, making those moons “super-habitable.”
Michelle Hill is an undergraduate student at the University of Southern Queensland (Australia) and the lead author of the study. She explains that exomoons could contain life:
“Because there are so … many giant planets in the habitable zone around their star, these giant planets are expected to have multiple moons, just like our giant planets do. So, really these moons potentially could be the worlds life is detected on first.”
No Biosignatures Detected so Far
However, until now, scientists haven’t detected signs of “life ingredients” on any exoplanets. They can see the exoplanets in the small dips in the light of their stars, but the moons are far smaller and more difficult to detect.
Sara Seager, Canadian astrophysicist and planetary scientist (MIT), studies exoplanets. She explains why searching for life in exomoons is difficult:
“Observations of exomoons in the search for life is very challenging, because the radiation coming from the exomoon will be mingled with the planet. The combined light of the exomoon and planet is already dwarfed by the light of the host star.”