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The power source for Earth ’s magnetic field may be magnesium that has been trapped in the core since our planet ’s crimson birth , a raw mannequin suggests .
Magnesiumis the fourth most unwashed factor in the Earth ’s out layer , but previously , scientists thought there was almost no magnesium in the core . Iron and magnesium do n’t easily mix , and researchers thought that theEarth ’s corewas mostly iron .
However , that intellection has changed because of recent theory proposing that the Earth was born from a series of violent hit with other protoplanets . During the impact , temperatures and atmospheric pressure were so intense that iron and alloy could combine in an alloy , concord to a study published today ( Jan. 20 ) in thejournal Nature . The study author add that smashing together two planetary body likely injected magnesium into the core . About 1 percent of the heart and soul ( by weight ) could be magnesium , the fresh good example shows . [ Religion and Science : 6 Visions of Earth ’s Core ]
" We think we now empathise why the Earth has had a magnetic field for the last 4 billion eld , and that the process will keep come about into the foreseeable future , " said tether study author Joseph O’Rourke , a graduate student in planetary scientific discipline at Caltech in Pasadena , California .
O’Rourke and take cobalt - author Dave Stevenson , a Caltech professor , created a model of Earth ’s formation to look into magnesium ’s behavior in the center . As Earth ’s core has easy cooled , magnesium - oxide mineral are " lead by the nose " out from the inwardness ’s branding iron and nickel note metal , the model indicate . This unanimous magnesium " snow " is light than the fluid metallic element and float outwards through the liquid - alloy out core , churn it and power the convection that produce the global magnetic theatre of operations .
The new model could facilitate figure out an authoritative question in world-wide science : What has powered the Earth ’s magnetized field for the past 4 billion years ? Many scientists call back iron cooling and solidify in Earth ’s core generates theplanet ’s magnetized field(also called the geodynamo ) . However , these models ca n’t explicate how the magnetized bailiwick was beget before the solid inner gist formed about 1 billion class ago . The new Mg model provides an alternative push source .
With the Modern model , " you do n’t have to stir anything crazy in the past tense to explain the geodynamo , " O’Rourke tell Live Science .
The new model involve to be verified with experimental tests , the researchers tell . There is little grounds indicate how Mg behaves at the temperatures and pressuresproduced during planetary collision .
" The idea is an interesting one , " said Rebecca Fischer , a postdoctoral blighter at the Smithsonian Museum of Natural History in Washington , D.C. , who was not involved in the written report . However , " before we can really , conclusively say how much magnesium goes into the core , we take better experimental information , " Fischer enjoin Live Science .
One group is already conducting such experiments . James Badro , a geophysicist at the Institut de Physique du Globe in Paris , has led survey that simulate the early Earth and look to affirm O’Rourke and Stevenson ’s molding .
" There ’s enough datum to win over us that our model of the atomic number 12 process run in universal , but screen out a lot of the details will require more experiments , " O’Rourke said .
A magnetized field is important for life because it shields the planet and the atmosphere from the solar malarky . Knowing how ancient Earth ’s magnetic field of battle quetch into gear mechanism may assist improve estimates of when life first appeared and inform the search for life on other planets .
