By Greta Keenan Okinawa Institute of Science and Technology
In 2005, the Hayabusa spacecraft developed by the Japan Aerospace Exploration Agency (JAXA) landed on Itokawa, a small near-Earth asteroid named after the famous Japanese rocket scientist Hideo Itokawa. The aim of the unmanned mission was to study the asteroid and collect a sample of material to be returned to Earth for analysis. Contrary to scientific predictions that small asteroids are barren nuggets of rock, photographs taken by the Hayabusa spacecraft revealed that the surface of Itokawa is strewn with different sized particles. Even more puzzling was the lateral separation of small and large particles – with large boulders occupying the highlands and small pebbles occupying the lowlands.
ESO PR — ESO’s New Technology Telescope (NTT) has been used to find the first evidence that asteroids can have a highly varied internal structure. By making exquisitely precise measurements astronomers have found that different parts of the asteroid Itokawa have different densities. As well as revealing secrets about the asteroid’s formation, finding out what lies below the surface of asteroids may also shed light on what happens when bodies collide in the Solar System, and provide clues about how planets form.