British scientists are preparing for the first ever UK-led expedition to look for meteorites in Antarctica, with the hope of finding an elusive hidden cache they suspect lies beneath the ice.
Antarctica has a lot of meteorites. Being dark, they are easy to spot on an icy white background, and are actually pushed towards the surface by upward flowing ice into what are known as Meteorite Stranding Zones. The new expedition, however, is specifically looking for iron-rich meteorites, which are much rarer than their rocky brethren and could help explain how planets are created.
The scientists from the University of Manchester, with logistical and operational support from the British Antarctic Survey at its Halley research station (yes, the one that looks like a bunch of Star Wars AT-AT walkers), are planning a reconnaissance mission in 2019 to scout for potential areas to search. The main expedition will likely then take place in 2020.
“We are delighted to be supporting this research project to hunt for the lost meteorites of Antarctica,” said Professor David Vaughan, director of science at British Antarctic Survey, in a statement. “The continent constantly reveals so many secrets about our Earth such as our past climate from ice and sediment cores so it’s great to work with UK researchers to help them solve another puzzle about Earth’s, and our Solar System’s, formation.”
Over two-thirds of the planet’s meteorites have been found in Antarctica, however the majority have been stony meteorites, with iron ones significantly underrepresented in the specimens collected. Iron meteorites are formed from the cores of planetesimals, tiny planets that were destroyed on impact with larger planetary bodies at the beginning of the Solar System. Why more haven’t been found is curious.
"In Antarctica, only 0.7 percent of the meteorites collected from these Meteorite Stranding Zones are iron-based, way below the 5.5 percent collected from the rest of the world," principal investigator Dr Geoffrey Evatt told IFLScience. However, "iron meteorites allow us to look into the cores of planets that used to exist billions of years ago. In so doing, we can learn how they formed, and thus how Earth is likely to have formed."
The research team believes that the “missing” iron meteorites may be found in a layer only a few centimeters under the ice. In a paper published in Nature Communications last year, they detailed their hypothesis that the meteorites have not been found because the Sun’s rays that penetrate the ice are warming the iron-rich rocks more than the non-metallic, causing them to sink and remain permanently trapped under the surface.
They plan to start searching three currently unexplored sites in the Shackleton mountain range area of Antarctica, within air travel distance of the Halley research station, in four years' time. A small-scale test mission to Svalbard, Norway, is planned for as early as 2018. The mission proper will involve using adapted technology originally designed for sweeping for landmines. The sensors will be dragged by skidoos across the ice to find the space material.
"To find these missing meteorites is the main challenge of our work. We're expecting to use two specially constructed wide-array metal detectors (based on landmine clearance technology), each around 10 meters across," Evatt explained. "With us expecting only around one iron meteorite per square kilometer, we'll clearly have to cover lots of terrain!"
“It will be exciting to see what the differences are between those samples we have to study in the lab, and the surface of an asteroid that has been pelted through time by impacting dust and other asteroids,” Dr Katherine Joy, who co-authored the study, also told IFLScience, when asked about NASA’s newly announced Psyche mission to observe the metallic-rich asteroid 16 Psyche.
Commenting on the opportunity to turn their mathematical hypothesis into an actual test, Dr Evatt said: “We now have the opportunity to commence on a truly exciting scientific adventure. If successful, our expeditions will help scientists to decode the origins of the Solar System and cement the UK as a leader in meteoritics and planetary science.”
Dr Evatt hopes this exploration will make the UK one of the "big players" in meteoritics and planetary science