Scientists say they've learned to crack some of the secrets of the cosmos by using meteorites that have fallen to earth, "reading" their magnetic information just like you would a hard drive.
Microscopic magnetic particles inside a meteorite carry memories of the asteroid it was born in, just like a hard drive contains information stored as variations in a magnetic field, and researchers say they've been able to read those meteorite "memories."
With a huge X-ray instrument known as a synchrotron, the scientists managed to read signals created inside a meteorite more than 4 billion years ago, says study leader Richard Harrison of the University of Cambridge in Britain.
Understanding how the metallic core of an asteroid solidifies as it is formed could lead to better understanding about the Earth's iron-rich core and its own magnetic field, he says.
"Ideas about how the Earth's core evolved through [our planet's] history are really changing at the moment," he says.
Scientist believe the origin of our planet's magnetic envelope is tied to the solidification of part of its core and the rest of it reaming liquid, he says.
"By studying an asteroid we get to see this in fast forward," Harris explains. "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."
Before the new research, it was thought the metal in meteorites could only provide a very poor magnetic recording, he says.
However, by beaming high-intensity X-rays into meteorite samples the team was able to detect and decode magnetic signals in magnetic particles inside the space rocks no bigger than a thousandth the width of a single human hair.
"We treat it as a kind of cosmic archaeology," Harrison says. "As if we found an ancient scroll with text written in tiny, tiny letters. And this method enables the meteorite to tell us its story."
The meteorite study offers a possible glimpse into what may happen to Earth's magnetic field billions of years in the future, the researchers say.
The magnetic fields generated in asteroids were much longer-lived than previously believed, they found, lasting for as long as several hundred million years after the asteroid formed.
Since they were created by a similar mechanism to the one that generates the Earth's own magnetic field, that finding could help answer many questions about the longevity and stability of magnetic field of both large and small solar system inhabitants, they say.
The Earth will eventually lose its magnetic field as its solid inner core gets better and the liquid outer core disappears, and when it's gone we'll no longer be protected from the Sun's radiation.
"There's no need to panic just yet, however," Harrison says. "The core won't completely freeze for billions of years, and chances are, the Sun will get us first."
