It came from outer space
THIS IS A cross-section through a grain from a well-travelled rock. It was brought to Earth from the Fra Mauro highlands of the Moon in 1971, by the crew of Apollo 14. Four billion years before that, though, it had made the journey in the opposite direction, according to an analysis by Jeremy Bellucci of the Swedish Museum of Natural History, published in Earth and Planetary Science Letters.
Fra Mauro is composed of ejecta from a celestial collision between an asteroid and the Moon, which excavated the biggest lunar impact basin, Mare Imbrium. Most of the samples returned by Apollo 14 are breccias created by this impact. Breccia is a type of rock formed by the higgledy-piggledy mixing of bits of other rock, and this two-gram grain was part of one such brecciated boulder.
Dr Bellucci’s analysis of the minerals in the grain, particularly its...