Can you tell the difference between comets, asteroids and meteors?

4 Jul 2016

Why is Halley’s Comet not called Halley’s Meteorite? Why is the computer game called Asteroids, not Meteoroids? This infographic should explain all.

Many people, should you query them, would struggle to explain the difference between comets, asteroids, meteoroids, meteors and meteorites. Rocks in space, why the need for such confusion?

There are different names because, believe it or not, not everything beyond the Earth’s atmosphere is identical. For example stars have lifecycles, sizes and power outputs. There are red dwarfs, red giants, super giants, hyper giants, nebulas, binary stars and beyond.

Meanwhile, dwarf planets are distinct from other planets like gas giants or ice giants, bringing us back to the original question: what’s the difference between a comet, asteroid and meteor?

Well, location, make-up and impact determines all. And it’s not just the average Joe or Joanne that gets it wrong, with a Google Doodle for all-round brilliant astronomer Caroline Herschel getting it quite wrong in the past.

Comets and asteroids

Starting with comets, these are generally small bodies of ice and rock in the solar system, distinct by their bright coma (a fuzzy, visible atmosphere due to solar radiation) and tail.

Celebrity comets include Halley, of course, as well as Comet 67P, home to one – and soon to be two – spacecraft resting places.

Asteroids, though, are made up of metals and rocks. While comets can get closer to the sun than some asteroids, the latter were formed nearer the sun and, lacking ice, they lose less mass the closer they are to the sun.

Most asteroids orbit in between Mars and Jupiter, whereas the vast majority of comets are way out in the Edgeworth-Kuiper belt, beyond Pluto. The line between dwarf planet and asteroid seems to be a bit vague, with some calling Ceres an asteroid.

Meteoroids, meteors and meteorites

Meteoroids are far smaller than asteroids, however, they are big enough to be significant. Often thought to have fragmented off passing asteroids – or even comets – meteoroids are the first episode of a three-part series that ends in a crater here on Earth.

Meteors are, essentially, shooting stars. When meteoroids burn up around the Earth’s atmosphere we can visibly see them shooting across the sky. This is the moment a meteoroid blossoms into a meteor.

Meteorites, then, are meteors that successfully negotiate their way through our atmosphere and onto the surface of our lovely planet.

Of course, if reading all that isn’t your thing, this fine infographic from Tim Lillis works just as well.

Comet meteorite

Main meteor image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic