Scientists first found natural superconducting materials in extraterrestrial objects by finding superconducting grains in two different meteorites that fell to Earth.
The discovery shows that meteorites are much more than space debris falling from the sky. Recent research has led to the discovery of meteorites delivering possible extraterrestrial proteins, minerals we have never encountered, and materials older than the solar system itself. But we've never seen anything like it before.
Superconductivity is a set of physical properties that provide a material 'ideal' electrical conductivity, which means that all electrical resistance within the material disappears, among other effects. This valuable phenomenon is incredibly rare in natural materials that have not been specially processed – and at least it is rare on Earth.
The researchers say extreme conditions in space create exotic material phases not seen on Earth as a result of astronomical events that can cause incredibly high temperatures and extremely high pressures.
Because of this, meteorites could be good candidates for searching for naturally formed superconducting materials forged in deep space. The only problem is that previous searches have never identified such superconducting compounds. At least until now.
In a new study by scientists at the University of California, San Diego, scientists examined fragments from 15 different meteorites using a technique called magnetic field modulated microwave spectroscopy to detect traces of superconductivity inside samples.
They got two superconductors: one in an iron meteorite called Mundrabilla, one of the largest meteorites ever found, discovered in Australia in 1911; another, rare ureilite meteorite called GRA 95205, discovered in Antarctica a quarter of a century ago.
The team's measurements, which were also based on vibrating sample magnetometry (VSM) and energy dispersive X-ray spectroscopy (EDX) techniques, both of these space rocks contain negligible amounts of extraterrestrial superconducting grains.
“Naturally occurring superconducting materials are unusual, but they are especially important because these materials can be superconducting in extraterrestrial environments,” says physicist James Wempler.
“These measurements and analyzes identified the likely phases as alloys of lead, indium and tin.”
The fact that superconducting grains have been found in two separate meteorites – and from such a small sample of cosmic rocks – means that more of these superconducting materials are likely to exist in astronomical environments, and their superconducting properties may in turn have all kinds of impact on their extraterrestrial environment.
“Superconducting particles in cold regions of space can affect the structure of stellar objects,” the scientists write.
The results are presented in PNAS.
Sources: Photo: Fragment of the Mundrabilla meteorite. (James Wempler)
