In 2009, NASA launched a satellite known as the Kepler telescope, whose main purpose according to Space.com was to discover new planets. And not just any planets; exoplanets. That is, planets outside of the solar system that orbit around Earth’s sun. And Kepler, which is expected to run out of fuel sometime later this year, accomplished its mission, discovering 2,342 planets, as of March, 2018.
Now, scientists at the University of California at Riverside have examined all of the Kepler exoplanet data and found that 121 of those newly discovered planets are both large and comprised largely of gas, rather than solid matter, similar to Jupiter in Earth’s solar system. But those planets also orbit within what scientists call the “habitable zones” of their solar systems, according to a paper published on Friday in The Astrophysical Journal.
That is, those massive planets are neither too far from their alien suns, nor too near, to support life. But how does life exist on oversized, gaseous planets, whether they are in “habitable zones” or not? The answer, according to the researchers, is it doesn’t. At least not on the planets themselves. Instead, according to a summary of the study published by Science Daily, life may exist on the moons circling those massive exoplanets.
The problem is, even with the powerful Kepler telescope, astronomers still cannot see the exomoons orbiting around the giant exoplanets. But they surmise that the moons must exist, because our own solar system is home to dozens and dozens of moons, mostly around the larger, distant planets, according to a report on the study by Gizmodo.
“There are currently 175 known satellites orbiting the eight planets within the solar system, most of which are in orbit around the two largest planets in our system, with Jupiter hosting 69 known moons and Saturn hosting 62 known moons,” University of California — Riverside astrobiologist Stephen Kane said. “The large number of moons in the solar system, particularly the large number orbiting the Jovian planets, indicate a high probability of moons orbiting giant exoplanets.”
So far, the existence of even a single exomoon remains purely a matter of speculation. Assuming that they do exist, however, the scientists believe that those moons may be even more conducive to the development of life than Earth itself — still the only known planet in the universe where life is confirmed to exist. Moons not only take in energy from the star, or sun, around which their host planet orbits, they also absorb energy reflected off the surface of that planet, according to a CNet report on the research.
“These potentially terrestrial giant satellites could be the perfect hosts for life to form and take hold,” the paper says.
Using their newly created database of habitable-zone exoplanets, the scientists hope to use that data to design new telescopes that could zero in on any exomoons orbiting the giant gas planets, helping scientists to determine whether alien life might exist on any of the faraway moons, a report on Astronomy.com explained.