Researchers led by a team at the the University of Cambridge have extracted tiny nanomaterials from a meteorites found in Argentina. A careful examination of the magnetic signatures left on these materials has revealed secrets about the early solar system, the life and death of the asteroid and provided some clues about the future of the Earth.

The Argentine meteorites are composed of crystals of gem-quality around a matrix of iron and nickel. Contained within the iron however are tiny particles of tetrataenite about 100 nanometers across, which is about one-thousandth the width of a human hair. This magnetically stable material holds a ‘memory’ of magnetic events going back to their birth in the early solar system, 4.5 billion years ago.

Researchers used the Bessy II synchrotron in Berlin, an extremely powerful x-ray microscope, to capture the highest-resolution paleomagnetic measurements ever made. Among other things they were able to capture the exact moment that the core of the asteroid which spawned the meteorite froze, killing its magnetic field.

“We’re taking ancient magnetic field measurements in nanoscale materials to the highest ever resolution in order to piece together the magnetic history of asteroids – it’s like a cosmic archaeological mission,” said PhD student James Bryson to Phys.org. Bryson is the lead author of the teams research paper which appears in the journal Nature.

The research demonstrated that magnetic fields generated by asteroids lasted much longer than previously thought, in many cases hundreds of millions of years. An asteroid’s magnetic field works in much the same way as the Earth’s. At the time they are formed, the core material is heated by radioactive material, as it spins the molten metal inside generates a magnetic field. This field then cools as the material cools and eventually disappears when the material freezes.

“It’s funny that we study other bodies in order to learn more about the Earth. Since asteroids are much smaller than the Earth, they cooled much more quickly, so these processes occur on shorter timescales, enabling us to study the whole process of core solidification,” said Bryson.

Scientists currently believe that the Earth’s core began to cool less than a billion years ago. It is not known however what affect this has had on the Earth’s magnetic field.

“Ideas about how the Earth’s core evolved through [our planet’s] history are really changing at the moment. We believe that Earth’s magnetic field is linked to core solidification. Earth’s solid inner core may have started to form at very interesting time in terms of the evolution of life on Earth. By studying an asteroid we get to see this in fast forward. We can see the start of core solidification in the magnetic records as well as its end, and start to think about how these processes work on Earth,” lead researcher Dr Richard Harrison, from the University of Cambridge, told BBC News.

The researchers believe that, given sufficient time, the Earth’s core could cool and eventually freeze. Like the asteroid, this would cause our planet to lose its protective magnetic field. It is unlikely that the Earth will have that much time.

“There’s no need to panic. The core won’t completely freeze for billions of years, and chances are, the Sun will get us first,” ” said Dr Harrison.