A meteorite spanning about 1.6 feet (0.5m) across and weighing 205 pounds (93 kg) fell from space some 30,000 years ago in what is now Britain. And after much sleuthing, researchers think they know where it came from and how it survived so long without weathering away. The giant rock was likely discovered by an archaeologist about 200 years ago at a ancient burial site near Stonehenge, according to said Colin Pillinger, a professor of planetary sciences at the Open University.
     Pillinger curated the exhibition 'Objects in Space' at the Royal Society's London headquarters (through March 30) and is the first time the public will get a chance to see the meteorite. The exhibition explores not only the mystery that surrounds the origins of the giant meteorite, but also the history and our fascination with space rocks.
     As for how the meteorite survived its long stint on Earth, researchers point to the Ice Age. "The only meteorites that we know about that have survived these long ages are the ones that were collected in Antarctica," said Pillinger, adding that more recently, some ancient meteorites have been collected in the Sahara Desert. This rock came from neither the Sahara Desert nor Antarctica, but rather the Lake House in Wiltshire.
     "Britain was under an ice age for 20,000 years," Pillinger said, explaining the climate would have protected the rock from weathering. At some point, ancient people likely picked up the meteorite when scouting for rocks to build burial chambers. Then, years later, an archaeologist likely found the rock while excavating those ancient burial sites. The archaeologist then brought the rock back to his house in Wiltshire, where its more recent residents took notice and alerted researchers. "The men whose house this was found at spent a lot of time opening these burial sites 200 years ago for purposes of excavating them," Pillinger said. "Our hypothesis is that the stone probably came out of one of those burial chambers."
     Other objects on display include a much smaller meteorite, weighing about an ounce (32g), and excavated from a grain pit where peoples of the Iron Age stored their crops. It was discovered in the 1970s at Danebury Hill Fort in Hampshire, though it wasn't until the 1980s when scientists analyzed metal in the walnut-size object did they realize its extraterrestrial origin.

Edited from Discovery News, Space.com, Huffington Post (9 February 2012)