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2 February 2017

Antarctic Expedition to Hunt for Meteorites Hopes to Reveal Secrets of the Early Solar System

Img: British Antarctic Survey 
Much can be learnt from the abundance of meteorites and other space rocks that have gotten caught up in the Earth’s gravity and plummeted to its surface over the millennia. They hold within the secrets of the solar system’s very creation, offering insights into how planets and other large bodies formed in the early life of the universe.

There are currently more than 35,000 meteorites catalogued in collections around the world, and of that figure a remarkable two-thirds were recovered from the frozen continent of Antarctica, making the South Pole a region of particular interest to researchers. Now, a British research team from the University of Manchester wants to take a closer look at one specific type of meteorite - those comprised predominantly of iron.

These iron meteorites were formed from the cores of planetesimals (small planets that were later destroyed by further planetary impacts), and could teach us a lot about how our solar system formed. It is also hoped that they will provide insights into the formation of our own planet, the iron core of which remains inaccessible to scientists for somewhat obvious reasons (there’s a blue, planet-looking thing in the way).

The go-ahead has now been given to the research team to launch the first British expedition of its kind - to collect the iron fragments of creation locked within the icy wastes of Antarctica. While the main expedition isn’t expected to take place until 2020, a preliminary trip to Antarctica will be made in 2019 and small-scale test missions will commence in 2018, located on the Arctic island of Svalbard.

The reason as to why such a large concentration of meteorites has been found in Antarctica over the years is twofold; firstly, the colour contrast between the dark rock of non-metallic meteorites and the snowy white backdrop make the fragments stand out clearly. Secondly, when meteorites do crash and bury themselves into Antarctica’s interior, the ever-moving ice sheets carry them off towards the coast. If, en route, said ice should encounter an obstacle such as a mountain range, the ice can behave in such a way as to force meteorites to the surface in areas known as ‘stranding zones’. Fierce winds strip these areas of their snowy covering and thus reveal the precious cargo underneath.

However, only 0.5% of meteorites found in Antarctica are made of iron. Global statistical averages indicate that this figure should be closer to 5.5%, so what happened to the rest of them?

The answer, it turns out, is something we’re rather familiar with here at Keep Me Warm - temperature. The properties of iron-rich meteorites, specifically their high thermal conductivity, means that they struggle to break the surface, as mathematician and glacial systems specialist DR Geoff Evatt explains:

“As they get nearer to the surface, the iron meteorites see the sun and absorb heat energy, and that allows them to melt back down. Iron has high thermal conductivity; it transfers heat from its top side to its underside where it can melt the ice below and essentially sink back down.

“That doesn't happen with the stony-type meteorites because although they absorb the energy, they can't transfer it as efficiently to their undersides.

“We think there must be a great mass of missing iron meteorites just under 30cm below the surface.”
A (not to scale) schematic diagram highlighting the boundaries and geometry and the mathematical model for the Antarctic situation, in which an englacial meteorite is exposed to solar radiation. - Img Source
The team plans to use technology adapted from landmine sensors, made possible due to a research grant from The Leverhulme Trust, to scan under the ice for signs of meteorite deposits. A prototype system is expected to be ready for testing at the UK’s recently relocated Halley Research Station in the Antarctic summer of 2018-2019.

Prof Tony Peyton, of Manchester's School of Electrical and Electronic Engineering, is charged with developing the scanning technology. He told the BBC:

“The issue is not so much signal to noise that we would have in our more extreme and demanding applications; the issue for us is really the ergonomics and practicality of engineering a system that can cover the area that we want and also cope with the environmental factors - the temperature range and the vibration.”

The exact location of the search is yet to be decided, but the fact that the research team will require access to both the Halley Research Station and logistical support from the British Antarctic Survey (BAS) will somewhat limit their options. As a result, the site is likely to be located around the Shackleton, Argentina or Pensacola ranges. Satellite images suggest the presence of extensive areas of dense blue ice in the proximity of these ranges – exactly the kind of ice the team are looking for, pushed upwards and swept clean by the wind.

If successful, it is hoped that the expedition will become an annual event. In fact, the team already have plans to collaborate with NASA’s recently announced Psyche space mission, as meteorite expert and Royal Society University Research Fellow Dr Katherine Joy explains:

“NASA has just announced the Psyche space mission which will visit an iron asteroid. That's going to a body made of exactly the type of material we hope to be collecting in Antarctica,

“Understanding the differences and similarities between what Psyche samples in-situ and what we see in meteorites in Antarctica is going to be critical to unlocking some of the secrets of the earliest days of the Solar System.”

Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.