Pieces of 4.6bn-year-old space rock ‘act as a time capsule from the earliest days of our solar system’, Nasa says
Discovered in 1999, it is a ‘rubble-pile asteroid’ which means it is a large jumble of space rocks compressed together by gravity. These rocks are thought to have broken off from a larger body, and are about 4.6 bn years old – meaning that they formed around the same time as the solar system.
Crucially, the asteroid is known to be rich in carbon-based substances and water-containing clay minerals – suggesting that liquid water was once present on the larger body from which Bennu formed.
