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In the 1950s geologists realized a meteorite found near Wedderburn in Australia had a composition like no other. Decades later a mineral never before known to occur naturally has been found in a slice taken from this rarity and the race is on to learn what this can tell us about a planet blasted apart in the early days of the Solar System.
The Wedderburn meteorite has proportionally more nickel (24 percent) than any meteorite ever seen. Moreover, it has an unusually high carbon concentration for an iron-nickel meteorite, although far lower than other types.
This composition alone suggests the material was once part of the core of a planet. Dr Stuart Mills of Museums Victoria told IFLScience this has been confirmed by some of the minerals within it, which require the high pressures of a planetary core to form without human assistance.
Although rare such rocks exist because, in the early days of the Solar System, some partially formed planets slammed into each other with such force both broke apart, scattering fragments from their cores across the inner Solar System. These items, like the more common meteorites with less exotic origins, have been wandering through space for 4.5 billion years before touching down on Earth.
Planetary scientists are keen to learn why the Wedderburn meteorite has more nickel and carbon than its counterparts, and what this says about the planet from which it came. Dr Chi Ma of Caltech has raised the stakes further by finding an iron carbide with the formula Fe5C2 and distinctive structure in the meteorite’s heart.
In American Mineralogist Ma names the new mineral edscottite after Professor Ed Scott, a meteorite expert whose PhD was on the Wedderburn meteorite.
Edscottite was first seen as a stage in the process of making steel. Chinese scientists have recently explored using the nanoparticles of the same material to improve tumor tracing. The molecules preferentially bind to cancer cells and make them visible to MRIs and other scanners, and therefore easier to target for treatment.
By tradition, minerals only get a name when found in nature – humans have found so many more ways of finding elements than we have discovered existing naturally that those we create ourselves are referred to by their formulae.
Having started at just 210 grams (7 ounces) and now lost much of its material for study the Wedderburn is so small the museum doesn’t want to cut its precious stone any further. Instead, it is appealing for some of the slices taken in the 1950s, now scattered in laboratories around the world, to be returned, and hopes these will satisfy planetary scientists seeking more natural edscottite.
Mills told IFLScience meteorites break up in the atmosphere, and where there is one there are almost always others of the same composition. Naturally, the museum would love to get its hands on these. Iron meteorites oxidize in wet climates but it is thought the meteorite struck the Earth around 800 years ago, and even another 70 years should not have destroyed other fragments.
The museum was recently presented with a large meteorite from the same region that a fossicker initially thought was a gold nugget. That one was special for its size, but even a few grams of natural edscottite would be a much greater prize.
