Saturn’s Moons May Be Younger Than the Dinosaurs—so Could Life Really Exist There?

If intelligent life could evolve on Earth in a few billion years, why couldn’t at least some simple organisms exist elsewhere in our 4.5 billion-year-old solar system?
Saturn’s Moons May Be Younger Than the Dinosaurs—so Could Life Really Exist There?
Enceladus, with its warm internal ocean, is thought to be potentially habitable. Marc Van Norden/Flickr, CC BY-SA
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Saturn is home to more than 60 moons—from the massive Titan and the crater-riddled Phoebe, to Enceladus with its geysers. Enceladus in particular has been put forward as a good candidate for harbouring microbial life, thanks to its warm internal ocean. After all, if intelligent life could evolve on Earth in a few billion years, why couldn’t at least some simple organisms exist elsewhere in our 4.5 billion-year-old solar system?

But now a new study, published in the Astrophysical Journal, has claimed that many of Saturn’s moons formed as recently as about 100m years ago—when dinosaurs still roamed the Earth. This challenges our understanding of the ages of moons in general and raises many new questions. How can we find out for sure? And could life still have evolved there in such a short time?

Revolution at Saturn

It has long been thought that nearly all of the major moons of our solar system’s giant planets were born from the cloud of gas and dust surrounding each planet as it grew. That would make them the same age as their host planet—4.5 billion years (the age of the solar system). However, these planets also have tiny moons that they acquired later, such as captured asteroids and comets in outer orbits, and chunks of debris from collisions in inner orbits.

Saturn's moons to scale (closest to the left, and excluding small outer moons). Those as far out as Rhea may be younger than about 100 million years. The sizes of the rings and the planet itself are indicated in the background. (NASA/ESA/DLR)
Saturn's moons to scale (closest to the left, and excluding small outer moons). Those as far out as Rhea may be younger than about 100 million years. The sizes of the rings and the planet itself are indicated in the background. NASA/ESA/DLR