Sciency Words: Carbonaceous Asteroids

Today’s post is part of a special series that first appeared on Planet Pailly. Every Thursday, we take a look at a new and interesting scientific term to help us all expand our scientific vocabularies together. Today’s sciency words are:

Carbonaceous Asteroids

As the name implies, carbonaceous asteroids (or C-type asteroids) have lots of carbon and carbon-containing compounds. Around 75% of the asteroids in the Solar System are believed to be carbonaceous, with most located in the outer asteroid belt. They’re dark in color, sort of like giant lumps of coal, which makes them difficult to find against the inky blackness of space.

But perhaps the most interesting thing about carbonaceous asteroids is that they can support life.


Bear with me a moment. Some scientists think life in our Solar System may not have originated on Earth or Mars or any planet. Instead, life may have begun on carbonaceous asteroids.

These asteroids contain many of the carbon-based molecules (including amino acids) necessary for life. They also generally have water ice, and at least when the Solar System was young, they would have retained plenty of heat.

And yet, the idea of life evolving and thriving on an asteroid is a bit of a stretch. Carbonaceous chondrite meteorites (fragments of carbonaceous asteroids that fell to Earth) show no signs of past or present biological activity. As a point of comparison, some meteorites originating from Mars offer at least circumstantial evidence of Martian life.

However, carbonaceous asteroids could become useful to life in the future. Space faring civilizations may want to harvest these asteroids for their resources, especially water, which could be used either for drinking or, if separated into hydrogen and oxygen, as rocket fuel. One large carbonaceous asteroid could keep a spaceship and its crew going for a long, long time.

At the very least, carbonaceous asteroids could provide valuable fuel for the imagination of a science fiction writer. What might happen if, while mining carbonaceous asteroids for their resources, we discovered that they do support life after all?

Next week, we’ll take a look at another type of asteroid – the siliceous asteroid.


Asteroid Mining from Astronomy Source.

Abodes for Life in Carbonaceous Asteroids? from Icarus.

Why Haven’t We Found Evidence for Life Starting in Asteroids? from the Planetary Society.

Article by James Pailly. Check out James’ blog for more great science articles.

  • Paulo R. Mendes

    Another great article! thanks, Mr. Pailly.

  • Leonardo Faria

    One of the worst Asimov’s short stories was just about mining ice from asteroids, not to space faring purpose but to sell it on Earth. Boy, it really sucked big time.