Sciency Words: Cryovolcano

Sciency Words is a special series here on Planet Pailly celebrating the rich and colorful world of science and science-related terminology. Today, we’re looking at the term:

VOLCANO

Okay, I guess this is a scientific term. It’s certainly an important concept in geology, but how about we do something a little more exotic for today’s Sciency Words post:

CRYOVOLCANO

Much better! Instead of a volcano spewing fire and lava and ash, picture a volcano that erupts with a mix of icy cold fluids and/or vapors which scientists call “cryomagma.”

How Do Cryovolcanoes Work?

When cryovolcanoes erupt, their cryomagma tends to include lots of liquid water, but at temperatures well below zero degrees Celsius. We all know that salt lowers the freezing point of water. Other substances, including ammonia and methane, can have the same effect.

Cold as they are, cryovolcanoes still require a heat source. This heat can be generated in several ways, including tidal forces, radioactive decay, or perhaps even a subsurface greenhouse effect whereby translucent surface ice allows light energy from the Sun to be trapped as heat energy deep underground.

Where Can We Find Cryovolcanoes?

Cryovolcanoes were first discovered on Triton, one of Neptune’s moons, in 1989. In 2005, the Cassini spacecraft observed cryovolcanic activity on Enceladus, a moon of Saturn, leading to rampant speculation about Enceladus’s possible subsurface oceans and possible organisms swimming in those oceans.

Enceladus remains on the shortlist of places astrobiologists want to check for alien life. And since cryovolcanoes often vent materials into space, we could easily go collect a sample.

Much of what we now know about cryovolcanoes is thanks to our ongoing observation and study of Enceladus.

How Rare are Cryovolcanoes?

So which are more common: volcanoes or cryovolcanoes? Thus far, regular volcanoes have been found on Earth and Io (one of Jupiter’s moons), and strong evidence of volcanic eruptions was just recently observed on Venus. Meanwhile, cryovolcanoes have only been confirmed on two worlds: Triton and Enceladus.

Based on that, it might seem like regular volcanoes are ahead, but hints of cryovolcanism have been found on a long, long list of moons in the outer Solar System (also Pluto).

At the beginning of this post, I insinuated that cryovolcanoes are “exotic,” but I’d guess that Earth-like or Io-like volcanic activity is far less common. Small, icy objects with their weird (to us) cryovolcanoes are probably scattered all across the cosmos.

Links

Active Volcanoes in Our Solar System from Geology.com.

Learning about Volcanic Activity on Triton from Bright Hub.

Ocean on Saturn Moon Enceladus May Have Potential Energy Source to Support Life from Space.com.