Sciency Words: Carbonaceous Asteroids

Sciency Words PHYS copy

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:


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.

Jy02 Skeptical Asteroids

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?


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.

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Today’s post is part of asteroid belt month for the 2015 Mission to the Solar System. Click here for more about this series.


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