The asteroid belt lies between the orbits of Mars and Jupiter.   It formed out of the same protoplanetary disc as the Earth, but many asteroids have barely changed since then.  Sara Russell explains what these time capsules can reveal about the Earth and how we will learn much more from the spacecraft currently fetching and returning asteroid samples to Earth.
Sara Russell is a professor of planetary sciences and leader of the Planetary Materials Group at the Natural History Museum in London.  Her research seeks to unravel how the solar system formed and cast light on questions such as how the Earth got its water and organic materials.  She even has an asteroid named after her.