Skip to main content

New theory suggests magnesium could be the key to understanding Earth's magnetic field





Two types of chemical convection in Earth's core. Precipitating a thin layer of magnesium-rich minerals at the top of the core provides as much energy for the magnetic field as forcing silicon and oxygen out of the entire inner core. Credit: Joseph O'Rourke


A pair of planetary scientists has come up with a new theory to help explain the mechanism behind the generation of the Earth's magnetic field. In their paper published in the journal Nature, Joseph O'Rourke and David Stevenson, both with the California Institute of Technology, suggest that magnesium that made its way to the core of the planet during its early history could be the key to understanding how the magnetic field was generated in the past and what drives it in the present. Bruce Buffett with the University of California offers a News & Views piece on the work done by the team in the same journal issue.


For many years, scientists have believed that the Earth's  is likely generated by energy that is released as the core cools and material solidifies, and radioactive decay—causing churning, the essence of the geodynamo. But, there is a problem with that idea, scientists also believe that the core did not cool enough to form an inner core, until approximately one billion years ago—that begs the questions of what caused the magnetic field to come about before there was sufficient cooling? The research pair with this new effort suggest it has to do with —they propose that it was introduced to the core during the time when the Earth was being formed, by collisions with other protoplanets, approximately 3.4 to 4.2 billion years ago.
They further suggest that magnesium could make up as much as 1 percent of the material in the core, and because magnesium is only soluble in iron at very high temperatures, they believe that it is slowly precipitating out to the boundary between the core and the mantle. That process, the team notes, would leave the iron behind denser, which would cause the release of energy, which they suggest could explain the power source behind the dynamo. Their theory would explain how it is that the magnetic field has been present for so long—it would also suggest that it continues to play at least a part in how the field is generated today—with magnesium possibly driving iron convection from the top part of the core while the release of light elements from the inner would drive convection from the bottom side.
The team used computer models in developing their theory which means experiments will have to be conducted to help bolster their ideas.
Labels:

Comments

Post a Comment

Popular posts from this blog

Einstein’s Lost Theory Describes a Universe Without a Big Bang

Einstein with Edwin Hubble, in 1931, at the Mount Wilson Observatory in California, looking through the lens of the 100-inch telescope through which Hubble discovered the expansion of the universe in 1929.  Courtesy of the Archives, Calif Inst of Technology. In 1917, a year after Albert Einstein’s  general theory of relativity  was published—but still two years before he would become the international celebrity we know—Einstein chose to tackle the  entire universe . For anyone else, this might seem an exceedingly ambitious task—but this was Einstein. Einstein began by applying his  field equations of gravitation  to what he considered to be the entire universe. The field equations were the mathematical essence of his general theory of relativity, which extended Newton’s theory of gravity  to realms where speeds approach that of light and masses are very large. But his math was better than he wanted to believe—...
Post a Comment
Read more

There’s a Previously Undiscovered Organ in Your Body, And It Could Explain How Cancer Spreads

Ever heard of the interstitium? No? That’s OK, you’re not alone  —  scientists hadn’t either. Until recently. And, hey, guess what  —  you’ve got one! The interstitium is your newest organ. Scientists identified it for the first time because they are better able to observe living tissues at a microscopic scale, according to a recent study published  in  Scientific Reports , Scientists had long believed that connective tissue surrounding our organs was a thick, compact layer. That’s what they saw when they looked at it in the lab, outside the body, at least. But in a routine endoscopy (exploration of the gastrointestinal tract), a micro camera revealed something unexpected: When observed in a living body, the connective tissue turned out to be “an open, fluid-filled space supported by a lattice made of thick collagen bundles,” pathologist and study author Neil Theise  told  Research Gate . This network of channels is present throughout ...
Post a Comment
Read more

First light-bending calculator designed with metamaterials

Exotic materials that bend light in extreme ways could be used to perform complex mathematical operations, creating a new kind of analogue computer. Tools for manipulating light waves have taken off in recent years thanks to the development of  metamaterials . These materials have complex internal structures on scales smaller than the wavelength of the light they interact with, and so they produce unusual effects. Most famously, metamaterials promise to deliver " invisibility cloaks " that can route light around an object, making it seem to disappear. Nader Engheta  at the University of Pennsylvania, Philadelphia, and his colleagues decided to explore a different use for metamaterials, one that adapts the  old idea of analogue computing . Today's digital computers are based on electrical switches that are either on or off. But before these machines were analogue computers based on varying electrical or mechanical properties. The  slide rule  is one example...
Post a Comment
Read more