Asteroids are linked to meteorites striking earth

The samples were dusted off the Hayabusa space capsule, which landed back in South Australia last year. They were analysed at The Australian National University (ANU).

"Previously there had been problems relating to the nature of asteroids with meteorites. Because the surfaces of meteorites are destroyed as they come in through the atmosphere," said Trevor Ireland from ANU.

"The samples from Itokawa are the previously unknown 'skin' of an asteroid and their investigation has confirmed that meteorites that land on earth are indeed related to the asteroids we see in space," said Ireland, the journal Science reports.

"The samples from the skin of the asteroid show that they have been exposed to cosmic rays and solar wind for less than 10 million years, meaning that the asteroid is very young in solar system terms, according to an ANU statement.

"The ages of the parent bodies are over 4.5 billion years old, and when the parent body had a collision, material was broken off and reassembled into Itokawa and sent on an orbit through the inner solar system.

"This demonstrates that inner solar system asteroids are only with us for a short time - geologically speaking," Ireland said.

The Hayabusa Mission involved two touchdowns on the asteroid.