Asteroids are all over the news this week. Not one, not two, but three of them whizzed by Earth within 48 hours of each other. And if that wasn't enough, the Hubble Space Telescope had a front-row seat for the break-up of a 240,000 ton asteroid. This edition of your Week in Geek is dedicated to these small, rocky bodies that we rarely see, but that still tell us a lot about the history of our Solar System.
At first, glance the video above might look like abstract art, but it is actually a visualization by astronomer Alex Parker of more than 100,000 asteroids known to be orbiting the Sun. The data comes from the Sloan Digital Sky Survey, a workhorse telescope located on a plateau in New Mexico that has observed more than a quarter of the entire sky.
The video shows the main asteroid belt, located between the orbits of Mars and Jupiter, as well as the Trojan class of asteroids known as Trojans that lead and follow Jupiter in its course around the Sun. The colors you see are artificial, but representative of the properties of different classes of asteroids: C-type (blue), S-type (purple/red/orange/yellow), and V-type (green). These classes are defined by chemical composition. C-type asteroids are composed of a lot of carbon and are characteristically dark and hard to see (as they don't reflect much sunlight). S-type asteroids are a little brighter and are composed of iron and magnesium silicates. V-type asteroids are one of the rarest types; they are basaltic and thought to be fragments of crust broken off from other larger asteroids, primarily Vesta itself.
The great thing about this video is it lets you see how the composition of the asteroid belt varies: the inner most region is green and therefore dominated by V-types, and the outermost region is much bluer, indicating more C-types. Astronomers knew most of this before, but in a numbers-on-a-page kind of way. Putting data like this into visual form reveals subtleties that might otherwise go unnoticed and allows astronomers both to reduce misclassifications and better identify outliers that could lead us in exiting new directions. Also, it's gorgeous.
Further geek from the week: