March 27, 2023


Epicurean Science & Tech

Enceladus is blanketed in a thick layer of snow

4 min read

Saturn’s moon Enceladus is shrouded in a thick layer of snow. In some sites, the downy stuff is 700 meters deep, new investigate indicates.

“It’s like Buffalo, but worse,” claims planetary scientist Emily Martin, referring to the famously snowy town in New York. The snow depth suggests that Enceladus’ extraordinary plume may possibly have been additional active in the previous, Martin and colleagues report in the Mar. 1 Icarus.

Planetary scientists have been fascinated by Enceladus’ geysers, made up of h2o vapor and other ingredients, due to the fact the Cassini spacecraft noticed them in 2005 (SN: 12/16/22). The spray almost certainly will come from a salty ocean beneath an icy shell.

Some of that drinking water goes to kind a single of Saturn’s rings (SN: 5/2/06). But most of it falls back on to the moon’s area as snow, Martin says. Comprehending the properties of that snow — its thickness and how dense and compact it is — could assist reveal Enceladus’ historical past, and lay groundwork for future missions to this moon.

“If you’re going to land a robot there, you require to realize what it’s going to be landing into,” states Martin, of the National Air and Room Museum in Washington, D.C.

To figure out how thick Enceladus’ snow is, Martin and colleagues seemed to Earth — specially, Iceland. The island nation hosts geological capabilities termed pit chains, which are strains of pockmarks in the ground shaped when loose rubble these types of as rocks, ice or snow drains into a crack beneath (SN: 10/23/18). Related functions clearly show up all more than the solar technique, which include Enceladus.

Pit chain craters in Iceland, like those demonstrated below, helped planetary scientist Emily Martin and colleagues validate that they could measure the depth of craters on Enceladus. Martin took this graphic for the duration of a discipline excursion.E. Martin

Former operate suggested a way to use geometry and the angle at which sunlight hits the floor to measure the depth of the pits. That measurement can then reveal the depth of the content the pits sit in. A couple of weeks of fieldwork in Iceland in 2017 and 2018 convinced Martin and her colleagues that the identical technique would do the job on Enceladus.

Utilizing photos from Cassini, Martin and colleagues observed that the snow’s thickness may differ across Enceladus’ surface. It is hundreds of meters deep in most sites and 700 meters deep at its thickest.

It is tricky to visualize how all that snow received there, however, Martin says. If the plume’s spray was constantly what it is currently, it would choose 4.5 billion many years — the full age of the solar program — to deposit that a lot snow on the floor. Even then, the snow would have to be primarily fluffy.

It appears to be not likely that the plume switched on the instant the moon formed and hardly ever improved, Martin states. And even if it did, later on layers of snow would have compressed the previously types, compacting the full layer and generating it considerably significantly less deep than it is today.

“It can make me imagine we really don’t have 4.5 billion years to do this,” Martin states. As a substitute, the plume may well have been much much more active in the earlier. “We require to do it in a much shorter timeframe. You need to have to crank up the quantity on the plume.”

The approach was intelligent, states planetary scientist Shannon MacKenzie of the Johns Hopkins College Used Physics Laboratory in Laurel, Md. Without having rovers or astronauts on the ground, there’s no way to scoop up the snow and see how considerably down it goes. “Instead, the authors are very cleverly utilizing geology to be their rovers, to be their shovels.”

MacKenzie was not included in the new work, but she led a mission strategy study for an orbiter and lander that could a person day check out Enceladus. 1 of the significant thoughts in that study was in which a lander could safely contact down. “Key to those discussions was, what do we hope the surface to be?” she says. The new paper could enable “identify the spots that are also fluffy to land in.”

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