Huge asteroid impact formed 'rubble pile' space rock
Local Japanese News In English
An asteroid larger than the Empire State Building is made from the guts of an even bigger space rock that broke apart in a cataclysmic impact, a new study finds.
The discovery is among the first scientific results based on dust samples collected by Hayabusa, a Japanese spacecraft that visited the asteroid 25143 Itokawa.
Itokawa is what's known as a rubble-pile asteroid-a body with such low density that the object can't be a solid hunk of rock and instead is most likely made from bits of debris held together by gravity. (See "Shaking Asteroid Sorts, Instead of Sheds, Its Rubble.")
Launched in 2003 by the Japan Aerospace Exploration Agency (JAXA), Hayabusa arrived at Itokawa in 2005. The craft returned to Earth last June, sending its sample-collection capsule to land in the Australian outback while the main body was destroyed in the fiery reentry. (National Geographic)
Source: News On Japan