Object of the Month – March 2023 – Cast of the Ashdon Meteorite
One hundred years ago, on 9 March 1923, a meteorite came from space and landed at Ashdon in north-west Essex. The fall was witnessed by a thatcher called Frederick Pratt who was working in a wheat field at Ashdon Hall Farm. He heard a ‘sissing’ sound and looked up to see ‘the earth fly up like water’. Later he dug up the stone from a depth of two feet with another farm worker called Curven. Frederick took it to the police station in Saffron Walden, then to his vicar in the village of Wendens Ambo. Reverend Francis W. Berry purchased the meteorite and donated it to the Natural History Museum where it was investigated by the Keeper of Minerals George T. Prior. He classified it as a stony chondrite meteorite. It contains minerals feldspar, pyroxene and olivine, white specks of nickel-iron and other minerals from which the solar system formed 4.5 billion years ago.
SAFWM : 1923.3 Cast of the Ashdon Meteorite ©
Chondrites
Chondrites are by far the most abundant class of meteorites, but they are also the most interesting, as they are thought to have been formed at the same time, and from the same stuff, as the inner rocky planets of our Solar System. They contain a mixture of fine-grained crystalline and glassy materials, and there are several different types, but they are all characterised by the presence of ‘chondrules’ – tiny, near-spherical beadlike objects about a millimetre in size. Chondrules are named after the Greek word chondrus, meaning grain, and are only found in meteorites. There is no scientific consensus on how chondrules were formed but they are thought to have once been molten droplets in space, formed at very high temperatures, which solidified and aggregated into asteroids.
The Ashdon Meteorite
The Ashdon meteorite is 12cm x 9cm x 6cm in size and weighs 1.27kg. When it landed it weighed 1.3kg, however two pieces were chipped off to find out what it was made of and the Natural History Museum took a thin section for microscopic examination. This plaster cast was made in 1926 using a mould of the original meteorite.
It is a flight-orientated stone. The smooth face of the meteorite was melted by the heat generated as it travelled through the Earth’s atmosphere from space. The face became a shield-shape as white hot molten rock was forced backwards by hypersonic flight. The other side of the meteorite is rough and irregular, as shown in the photograph below.
Meteor Shower Landing Soon! To celebrate the centenary of the fall more meteorites will be on display from Sunday 12 March to Friday 14 April. These rocks from space include meteorites that landed in Africa, Greenland, North America and Russia. You will also be able to see pieces of rock ejected from Mars and the Moon which landed on Earth as meteorites.
In association with the upcoming meteorite display, the museum shop will be stocking Gerald Lucy & Mike Howgate’s booklet, The Ashdon Meteorite for a very reasonable £3 per copy.
