Researchers have decoded ancient recordings from fragments of an asteroid dating back billions of years to the start of the Solar System.
They found tiny "space magnets" in meteorites which retain a memory of the birth and death of the asteroid's core.
Like the data recorded on the surface of a computer hard drive, the magnetic signals written in the space rock reveal how Earth's own metallic core and magnetic field may one day die.
The work appears in Nature journal.
Using a giant X-ray microscope, called a synchrotron, the team was able to read the signals that formed more than four-and-a-half billion years ago, soon after the birth of the Solar System.
More at the link, and it's beautiful to look at. it concludes by stating the Earth's magnetic field will likely die off when the core completely freezes, and Earth will no longer be protected from the Sun's radiation.
But "There's no need to panic" said Dr Harrison. "The core won't completely freeze for billions of years, and chances are, the Sun will get us first."