Almost certainly you saw the chart – the Earth's layers are exposed as a slightly more complicated hard-boiled egg. The bark we live on is actually a thin sheath, and the hot (but still hard) mantle forms a thick layer beneath it. In the center ̵
While you will never visit the core, it will deeply affect your life. Earth's magnetic field is produced by the convection of the liquid outer core, which directs the compasses and protects us from the effects of the solar wind. The history of the Earth's magnetic field is a big issue – not least because we are not really sure when the inner core has solidified.
Magnet … well, you know
There are actually geological records of the magnetic field. The small crystals of the magnetic minerals in the cooling magma will align with the magnetic field before they are frozen in place. This may be useful because the Earth's magnetic field often flips the poles (meaning that the compass needles would point geographically to the south). The orientation of these mineral needles also shows how close they are to the equator when they are formed. The information captured by these minerals was the last piece that actually cracked the plate tectonics case and allowed us to find out where every continent was in the past.
We can also understand how powerful the magnetic field is. of these records. This is what a team led by Richard Bono and John Tarduno of Rochester University was most interested in when they analyzed about 565 million annual rocks in Quebec.
We do not have much data from this period, some researchers suspect it may have been when the inner core finally began to harden. In this case, the magma rocks, which the researchers worked on underground cooling, means that their record probably covers about 75,000 years. This should be longer than it normally takes to invert the magnetic poles, so any temporary changes like this should be averaged.
The team found that the magnetic field was incredibly weak at the time surveyed. The late Jurassic period is evidenced by the presence of an abnormally weak magnetic field, but this is only about a fifth, as strong as that period of time. In addition, magnetic poles seem to rotate extremely often. This is a very strange behavior.
These data actually coincide with the limited information we have of the periods closest to that time, which is also quite odd. And the study becomes really interesting when you compare it with the simulations of the history of the Earth's core. Some of these simulations predict that the hardening of the inner core is relatively recent geologically, which is happening at that time. In these models, the reorganization of the kernel causes the magnetic field to disappear for a while, turning in a weakened state.
Researchers say their evidence fits into a scenario where the inner core began to cure about 565 million years ago – nearly 4 billion years in Earth's life. This adds to the question of how the magnetic field generating "geodynamics" in the nucleus had previously appeared and how it lasted so long. He also adds to the overwhelming list of strange things that happened in this chapter of Earth's history, which includes a remarkable evolutionary explosion of a complex animal life.
In a summary accompanying the report in Carnegie Institution for Science researcher Peter Driscoll (who is not involved in the study) outlines the work needed to follow this succinct hypothesis: "Additional palaeo-magnetic observations, both directions and intensities, are the obvious next step towards a clearer picture of the state of the kernel at that time. Curing and iron conductivity experiments will further reduce the thermodynamics of the core. Finally, the numerical models of the developing nucleus can provide detailed predictions to check how all these components come together. "
And if this timeline of inner core formation is correct, Driscoll writes that" the formation of the inner core may have  2019. DOI: 10.1038 / s41561-018-0288-0, 10.1038 / s41561-019-0301-2 (for DOIs).