It's not every day that astronomers get to witness an asteroid crumbling into a bunch of glowing chunks hurtling through space. In fact, it has never been wintessed before — until now. Scientists from NASA and the European Space Agency announced today that the Hubble Space Telescope has photographed the fragmentation of an asteroid, designated P/2013 R2, into 10 separate chunks, each with its own glowing comet-like dust tail. The four largest chunks are about 400 meters in diameter, which is more than four football fields wide. "This is a really bizarre thing to observe — we've never seen anything like it before, ”said co-author Jessica Agarwal of the Max Planck Institute for Solar System Research, Germany, quoted in a NASA/ESA press release about the discovery. The video above shows a sequence of Hubble observations of the asteroid over a little more than two months in late 2013 into January. (The sequence plays several times.) The fragments move around with respect to each other, and new chunks seem to break off. How did it happen?
An illustration of one possible explanation for how asteroid P/2013 R3 disintegrated through the influence of sunlight on the highly fractured chunk of rock. Source: NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI) The illustration above shows one theory. Under the influence of 4.5 billion years of pummeling from collisions with other asteroids, P/2013 R3 was likely not so much a solid chunk of rock as something more akin to a rubble pile, at least internally, with lots of fractures and weak areas. Over time, solar energy shining on the asteroid was absorbed and reradiated as heat. But the irregular surface would have meant that some areas radiated more heat, and others less. This, in turn, would have resulted in torque on the asteroid that slowly caused it to rotate faster and faster — until it fragmented.