Explaining strange asteroid shapes

It may not occur to most people, but asteroids are shaped funny, and they can also change shape. Now astronomers think they know why, as reported by Lee Pullen at Space.com.

But what changes the asteroids' shape? Gyula [Szabó from the University of Szeged in Hungary] and his team have shown that asteroids change shape from elongated to roughly spherical due to being impacted during their lifetimes. They are like pebbles on the beach that become worn smooth over many years -- only in space, erosion is caused by small impacts as rocks knock into each other and chip pieces off.

Impact specialist Jonti Horner from the UK's Open University agrees with Gyula. "The results make sense," he says. "Catastrophic impacts create a huge slew of fragment shapes, like the shards of a broken bottle. The debris then are weathered over time and smoothed towards sphericality by small impacts."

Space pebbles. Cool stuff.