Sciency Words: Outgassing

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we talk about science or science-related terminology.  Today on Sciency Words, we’re talking about:

OUTGASSING

Okay, I’m tempted to start this blog post with a fart joke.  But I won’t.  I’m too classy for that.  Outgassing is a normal and natural process that occurs on all the rocky and/or icy planets and moons of our Solar System.

According to the Oxford English Dictionary, the earliest known usage of “outgas” or “outgassing” is this 1919 paper titled “The Relative Adsorption of Mixtures of Oxygen and Nitrogen in Cocoanut Shell Charcoal.”  It’s a thrilling read.

Basically, solid substances (cocoanut shell charcoal, planetary regolith, etc) can get gas particles stuck to their surfaces or trapped inside them.  Gradually, these gas particles will escape.  The process of gas particles gradually escaping from a solid material is called outgassing.

On a planetary scale, outgassing is a major contributing factor in the formation of a planet’s atmosphere.  Or at least that’s true for small, terrestrial planets like Mercury, Venus, Earth, and Mars.  Gas giants tend to form their atmospheres through a different process (so before anyone makes a comment about this, there is no outgassing happening on Uranus).

So the main takeaway of today’s post is this: solid materials often have gas particles trapped inside them.  On a planetary scale, the gradual release of these gas particles helps to form planetary atmospheres.  This is known as outgassing.

Or you could just say terrestrial planets fart, almost constantly, and that’s where their atmospheres come from.