by The search for life beyond Earth has driven searchers into all sorts of possible habitats—not just on the growing list of Earth-like exoplanets, but elsewhere within our own solar system.
It’s probably the first option that comes to mind Marssome scientists believe that there are still oases of liquid water beneath its bare surface, Not long ago, phosphine, a possible indicator of biological decay, was detected in the atmosphere of Venus to cancel a debate about whether life could exist in the clouds of that hellish planet. And for many years, scientists have been thinking could life exist in the skies of gas giants like Jupiter.
But one area that many scientists have not considered in their lifetime is the series of rings that crown Jupiter, outside the atmosphere of the gas giant. These rings are actually belts, like the ones that surround the gas giants of our entire solar system mainly composed of water-ice particles, some as small as grains of sand, others as large as mountains. Could there be life?
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Scientists generally believe that an environment that can support life as we know it requires three main components. The first is some kind of energy source: typically, the heat and light from a star, which creatures could tap into for photosynthesis. The second is organic matter: they contain chemical compounds of carbon that could form living things in the first place. The third is liquid water. Everything from the moon to distant comets may contain water in frozen form, but the water must be liquid for life to thrive.
Take the amazing rings of it Saturn. Within them, two of the three necessities for life as we know it are known. Even out here, there is enough sunlight to support life. And while Saturn’s rings may seem like an unlikely place for organic matter to exist, NASA’s Cassini mission received that carbon condenses as it rains butane and propane into the atmosphere of the gas giant from its innermost D-ring.
Unfortunately, the third ingredient – liquid water – is missing. “You have organic matter falling into the rings, and there’s sunlight, but there’s no liquid water,” Matthew Tiscareno, a planetary scientist at the SETI Institute in California, told Space.com. “There is a lot of water, but it is all frozen.”
So that makes life – again, at least as we understand it – a tenuous possibility in any of the rings of our solar system, all of which are too far out and too cold to melt water ice. But if there were rings in another star system, say, closer to their sun, then the sun’s heat could give us the liquid water we’re looking for.
Despite their best efforts, scientists have yet to see rings around an inner planet, our own Solar system or another, so they can only make educated guesses as to what those rings look like. Instead of the water-ice rings we get around Jupiter or Saturn, these hot rings may be collections of rocky boulders.
Unfortunately, it would still be difficult to keep water in liquid form with space around it; without an atmosphere, liquid water tends to evaporate. “You need an atmosphere to keep liquid water stable,” Tiscareno said. “It doesn’t have to be much different than asteroids.”
Many scientists think that simple life may have arrived on Earth billions of years ago riding on an asteroid that hit much younger life: a theory known as panspermia. That theory got a boost in 2023, when scientists received uracil — an organic compound and one of the components of RNA — in a sample taken by Japan from the asteroid Ryugu Hayabusa 2 mission. On the other hand, it is doubtful that these compounds actually appeared on the asteroids themselves.
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For now, the lifetime possibility is one that ring investigators don’t usually concern themselves with. But that doesn’t mean the idea isn’t completely outside the realm of what scientists might consider. “I like the idea of thinking about creative places where life could be,” said Tiscareno.
And rings are fascinating to astronomers for many reasons not directly connected to the search for life. For one thing, they are natural instruments, allowing astronomers to examine their host planets in unique ways – watching meteorites hit the rings, for example. In another case, examining the rings of a planet tells us a lot about how that planet evolved – only certain conditions could allow rings to develop into the structures that astronomers see.
Thirdly, rings are disks: in other words, they closely resemble the types of disks that form planetary systems in the first place. Scientists can’t see the disks of newly formed protoplanets around other stars yet (at least not in detail), and they can’t create a timeline for seeing the early solar system – but they can certainly see the rings of Saturn.
