Normally when we hear about an asteroid breaking up, it's because it can't stand up to the heat of passing through the Earth's atmosphere. Asteroids break up all the time, it's just that we only tend to notice them after they have split into a million pieces. This time however, astronomers just happened to be looking in the right place at the right time to capture the breakup of a large asteroid in its very early stages.
P/2013 R3, to use its catchy name, was first spotted by astronomers last September, and they thought it looked pretty interesting so they passed on the information to their colleagues at the Keck Observatory in Hawaii. Seeing what appeared to be an asteroid surrounded by a fuzzy cloud, they figured it was time to bring out the big guns so they convinced the folks controlling the Hubble Space telescope to spin it around so they could take a look.
With the extra clarity of the space telescope, it became evident that P/2013 R3 was spinning itself apart very slowly, and had separated into ten large asteroids. The four biggest pieces were each about 200 yards across, or ten times the size of that Chelyabinsk meteor which landed in Russia last year, and we all know how much damage that one did.
Astronomers have ruled out a collision as the cause of the breakup, and they suspect that the centrifugal forces from the asteroid's rotation are simply pulling it apart. This so-called Yorp effect has been theorized about in the past, but this is the first time it has actually been observed. The pieces are only moving apart from each other at a leisurely one mile per hour, so all of the pieces are moving in pretty much the same direction.
Luckily for us, the astronomers say that most of the pieces will get burned up by the Sun, but there is a chance that some may enter Earth's atmosphere as meteors. Let's just hope it's not one of those cruise ship-sized pieces.Check out the gallery to see the pictures captured by Hubble showing the disintegrating asteroid, and a video animation of the images set to some suitably spacey music.