- A study of Enceladus images from the Cassini orbiter has revealed new clues as to the age of the ice on different parts of the moon.
- The moon’s south pole is covered in new ice, which is expected, but its northern hemisphere also has young ice, which was a surprise.
- Enceladus is one of the few places in our solar system where extraterrestrial life may exist in some form.
Of all the planets and moons in our solar system, Saturn’s icy moon Enceladus appears to be one of the few that may support life in some form. It has a solid shell of ice, but deep beneath the ice, there’s liquid water. We know this because we’ve seen it spewing out of massive fissures in the ice.
Now, researchers using data from the NASA Cassini space probe have detected what they believe is the signature of fresh ice not just at the active south pole of the moon, but also in the northern hemisphere, which is a new finding.
The research, which was published in the journal Icarus, uses infrared spectrometer data to estimate the age of the ice surrounding the moon. Fresh ice produces a different signature than old ice, and this data allows scientists to get a pretty good idea of when the ice formed.
The first discovery wasn’t a surprising one: Enceladus’s south pole is absolutely covered in fresh ice. NASA has spotted this happening, with huge plumes of liquid water spewing from cracks in the moon’s south pole. That water freezes almost instantly and much of it eventually settles back down onto the south polar region.
However, the Cassini spacecraft took images of all sides of the moon, and, as it turns out, there’s a good bit of fresh ice around the northern hemisphere as well. It’s not nearly as dense as the fresh ice near the south pole, but it’s an indication that the moon’s northern hemisphere was active in the not-so-distant past.
It’s impossible to say how the new ice got to the northern hemisphere based on the current observations. Either it enjoyed similar activity to the south pole, with cracks forming and freshwater spewing out, or it was a more gradual process, with water leaking out of smaller holes over time.
“The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there,” Gabriel Tobie, co-author of the research, said in a statement. “Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines.”
As the search for life in our solar system continues to heat up, worlds like Enceladus, Europa, and Titan will get more and more attention. Understanding the mechanisms by which their surfaces work is going to be very important if we hope to grasp how life might form on one or all of them.