Mimas, Saturn’s cryptic-looking moon, is awfully deceptive.
The small moon is dominated by an 80-mile-wide crater, giving it the appearance of the grim
Other moons, like Saturn’s Enceladus and Jupiter’s Europa, have cracked surfaces or
“When you look at Enceladus and Europa, there’s clearly an engine in these moons that is running,” Alyssa Rhoden, a planetary scientist who researches ocean worlds, told Mashable. “When you look at Mimas it’s the opposite — it can’t possibly be an ocean world.”
Or so Rhoden thought. Looks are deceiving.
In new research
Credit: NASA / JPL / Space Science Institute
Credit: NASA / JPL / Space Science Institute
Mimas does have an attribute that could allow it to harbor an ocean. Its orbit around Saturn is highly eccentric, meaning it gets tugged and stretched as it swings close to the powerful gravitational force of the planet and then orbits farther away. (Each orbit takes just 22 hours and 36 minutes!) This process, called “tidal heating,” creates vast amounts of heat in ocean worlds like Europa.
With this reality in mind, Rhoden, a principal scientist at the
The researchers calculated that if there was indeed an ocean inside Mimas large enough to trigger its wobble, the water would exist beneath an icy shell some 14 to 20 miles thick. So they ran computer simulations of how the heating (from tidal heating) would impact the ice on Mimas. Unexpectedly, it showed an ocean under 14 to 20 miles of solid ice.
“We came up with exactly the right number,” Rhoden said.
This isn’t, Rhoden emphasizes, nearly certain proof that Mimas harbors an ocean. But there’s now compelling evidence that an ocean could exist there, with the information available.
“There’s a lot of different ways life might be able to emerge.”
Oceans, as we know on Earth,
Sometimes, the search for life gets narrowed down to “habitable zones” in solar systems, which are the relatively narrow regions where liquid water could exist on a planet’s surface. Earth, for example, exists in our solar system’s habitable zone.
Europa and Enceladus, located in the frosty regions of our solar system, are well outside the habitable zone. But these worlds harbor oceans. And potentially, life may have emerged there.
“Habitability is not one swath of a solar system,” said Rhoden. “There’s a lot of different ways life might be able to emerge.”