Vesta
The second-largest object in the asteroid belt and the likely home of the howardite, eucrite and diogenite meteorites.
Vesta is a giant asteroid about 525 kilometres across, discovered by Heinrich Olbers in 1807. It is the brightest asteroid seen from Earth and, at its best, can just be glimpsed with the naked eye from a very dark site. Unlike most asteroids, Vesta melted early in its history and separated into an iron core, a rocky mantle and a lava crust, making it something like a tiny planet.
Its south pole bears a huge impact basin called Rheasilvia, about 500 kilometres wide, with a central peak roughly 20 kilometres high. That impact, and an older one beneath it, blasted out vast amounts of rock. Some of it forms a family of small 'Vestoid' asteroids, and some reaches Earth as the HED meteorites: howardites, eucrites and diogenites. NASA's Dawn spacecraft orbited Vesta in 2011–2012 and found its surface minerals match these meteorites.
The eucrite Millbillillie, which fell in Australia in 1960, and the howardite Kapoeta, which fell in what is now South Sudan in 1942, are classic examples. HED stones often have a shiny black fusion crust over a pale grey interior full of broken fragments.
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Level: Explorer Ages 10 and up