Bad Astronomy

Asteroid comparison chart

Emily Lakdawalla – scientist, blogger, and all around cool chick – has just posted a totally awesome scale diagram comparing every asteroid and comet visited by spacecraft. It features pictures of all the rocks, each of which she has carefully resized so you can see just how big they are relative to each other:

Whoa. Look how big Lutetia, just visited by Rosetta, is compared to everything else! And yet, at 130 km across, it’s a dot compared to our Moon. In fact, you could smash together all the known asteroids in the main belt between Mars and Jupiter and they’d be far smaller than our rocky satellite.

Still, small doesn’t mean “uninteresting”. These rocks in Emily’s diagram are all fascinating beasts, and the more we learn about them the more compelling they become. And there’s more to come, with the Dawn mission about to see the big asteroids Vesta and Ceres up close… and go read Emily’s blog about this to see how they’d fit on the diagram (hint, they don’t, and by a long shot). You’ll also find a much larger version of the diagram there, and you really, really should look at it. Wow.