Museum Notebook:The Mokoia meteorite

The Mokoia Meteorite - An Amazing Space Rock

NASA recently announced that organic molecules have been found on Mars, delighting space enthusiasts, but they neglected to add that extraterrestrial molecules can also be found in Whanganui.

Every living thing on Earth is made of organic molecules and their presence points to the possible existence of living cells. While it is unlikely that sophisticated aliens will be found on Mars, any type of primitive life, even fossilised, increases the possibility of discovering more complex life elsewhere in space.

Organic matter from space is rare but it has occasionally turned up within meteorites, debris left over from the formation of the solar system more than 5,000 million years ago. Meteorites contain varying quantities of rock and metal.

Captured by Earth's gravity, they fall through the atmosphere, turning into fireballs and exploding before impact.

The Mokoia meteorite in the Whanganui Regional Museum collection is actually two parts of a much larger rock of carbonaceous chondrite, the rarest of all meteor types. Carbonaceous chondrite is mainly composed of carbon: the atom that defines organic molecules.

The fragments fell at Mokoia, about 30 km north of Whanganui, on 26 November 1908. In the middle of an ordinary November day a flash caused witnesses to look up at a bright ball of light rushing overhead trailing a silvery tail.

Mokoia via Google

Whanganui witnesses spoke of the delay between the light and the subsequent loud explosion, described as a "cannonade", heard from North Taranaki to Hawke's Bay. The main body of the meteor was seen falling into the sea off Castlecliff Beach in Whanganui.

There were determined efforts to locate the extra-terrestrial visitor, but only a twist of fate preserved it for meteorite hunter W. Syme. If it had embedded itself in the ground he could easily have missed it. However it struck a tree near Mokoia and was still smouldering days later when he reached it.

The meteorite was passed to the Museum and it was only later that analysis revealed how rare and amazing the space rock is. The supernova star explosions that enriched our region of the galaxy and eventually gave rise to our solar system, threw out plenty of carbon and lumps of it still float about until they hit a planet like ours.

It is possible that NASA's organic carbon molecules arrived on Mars the same way as the carbon in our meteorite. Mars has probably also been dusted with this primordial material over the years.

Some theorists suggest that carbon-rich meteorites may have contributed to the beginning of life on Earth. Consequently, scientists from around the world have requested and received small pieces of the Mokoia meteorite.

The resultant scientific papers record that it also contains amino acids, the building blocks of proteins. They aren't in the proportions made by life on Earth but their presence is significant and amazing. We are extremely fortunate to have this very rare piece of space rock here in Whanganui.

Margie Beautrais is a Whanganui Regional Museum educator.