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An Expedition to Search For Antarctica's 'Lost Meteorites' Has Been Approved

What's hiding below the ice?

FIONA MACDONALD
2 FEB 2017
 

Antarctica should be the perfect place to find meteorites - the dark rocks are easy to spot against the ice-covered landscape, and upward-flowing ice regularly dumps buried meteorites onto the surface.

But, oddly enough, relatively few iron-based meteorites have ever been found on the continent, leading scientists to suspect that something is causing them to get lost beneath the ice. Now, an expedition has been green-lit to go and look for them.

 

If the team, funded by the British Antarctic Survey, can find some of these iron-based meteorites, it could give us crucial clues about how life got started on our planet, and how the rest of the Solar System formed.

"We now have the opportunity to commence on a truly exciting scientific adventure," said expedition leader Geoffrey Evatt, a mathematician from the University of Manchester.

"If successful, our expeditions will help scientists to decode the origins of the Solar System."

Iron meteorites are so interesting to researchers because they're formed from the cores of planetesimals - small planets in the early days of the Solar System that went on to be destroyed by further planetary impacts.

Getting a better understanding of their composition and age can tell scientists a lot about how planets are formed, and how the Solar System evolved.

But that's if they can find them.

 

Two-thirds of the world's meteorites have been found in Antarctica, many of them in areas of glacial ice known as meteorite stranding zones, which force meteorites to the surface with regular uprisings of ice.

But back in 2012, Evatt worked with glaciologists to show that iron meteorites have been conspicuously missing from those discoveries.

In fact, only 0.7 percent of the meteorites collected from the meteorite stranding zones are iron-based - compared to 5.5 percent of the meteorites collected from the rest of the world. 

"Meteorite collection data shows that iron and stony-iron meteorites are significantly under-represented from these regions as compared with all other sites on Earth," Evatt and colleagues wrote in a paper in Nature Communications last year.

The team hypothesises that the iron meteorites are getting heated up by sunlight in Antarctica as a result of their metallic content, and melting the ice surrounding them. This then causes them to sink and get trapped below the surface.

They concluded that the meteorites are most likely hidden as a sparsely distributed layer, just a few centimetres beneath the surface of the Antarctic ice - which means they wouldn't be that hard to retrieve, but have been masked from previous meteorite-hunting expeditions.

Their approved mission proposal will use new technology based on metal-detectors to scan for the hidden meteorites. 

The team will test the technology next year on the Arctic island of Svalbard, and make a preliminary visit to Antarctica in 2019. The main expedition is expected to take place in early 2020, when the researchers will find out if their hypothesis is correct.

"The whole notion of a layer of missing meteorites in Antarctica came out of blue-sky discussions at an interdisciplinary workshop, between a group of applied mathematicians and glaciologists, back in 2012," said Evatt.

"Having subsequently turned those initial ideas into firm scientific reasoning, we now have the opportunity to put our mathematical hypothesis to the most extreme of tests."

Until they get down there, there's no way of knowing where Antarctica's missing meteorites are hiding - or if they're even there at all.

But seeing as we can learn so much from them, we're glad scientists will soon get the chance to find out. 

You can read the team's paper predicting the location of the lost meteorites in Nature Communications.

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