Millbillillie Meteorite

Millbillillie Meteorite

The Millbillillie meteorite is named after the cattle station in Australia, where it fell in October 1960. Two cattle station workers witnessed a fireball blaze across the sky and fall to the North of them. However, no initial search for the meteorite was carried out and specimens were not recovered until ten years later. Since then between 100-300 kilograms have been recovered. Due to the red soil in the area, many specimens have red stains on their black fusion crust.

Millbillillie is classified as an achondrite eucrite. An achondrite is a stony meteorite which does not contain the small mineral granules known as chondrules. This indicates that it originated from a body large enough to have melted and separated into a layered structure of core, mantle, and crust. Eucrites are basalts that come from the crust and are formed by lava flows on the surface. They are very similar to terrestrial igneous rocks, as they are formed by the same processes.

Eucrites are part of the HED meteorite subgroup, which stands for "howardite–eucrite–diogenite". These are all believed to originate from the asteroid 4 Vesta, the largest asteroid in our Solar System. NASA’s Dawn spacecraft confirmed this theory when it scanned the surface of the asteroid in 2011 and collected data about its chemical composition. Vesta has a huge crater at its south pole which is 460 kilometres across and 13 kilometres deep. The impact that caused this crater ejected over two million cubic kilometres of rock into space. This single impact is believed to be the source of about 5 per cent of meteorites found on Earth.