By bombarding a meteorite with X - rays , scientists have make out to record ancient magnetic message formed in the other solar system , some 4.5 billion eld ago . These recordings , which were retained by microscopical “ space magnets ” engraft in the cosmic debris , tell us the tale of the second when an asteroid ’s metallic core suspend , toss off its magnetic playing field . invitingly , these memory board may allow us to peer into the upstage future of our own major planet , concede new penetration into what may happen to its heart and soul as it continues to block . The work has been write inNature .
Scientists are interested in consider asteroids because they act astime capsule , comprise important piece of entropy about the history of our solar organization . meteorite are fragments of these rocky worlds that have collided with Earth , volunteer scientists an opportunity to examine the space debris ’ past .
The 4.5 - billion - year - old meteorites used in the work were collected fromArgentina , but they originated in the asteroid belt between Mars and Jupiter . These particular case of junk are cognize aspallasites , which are in the first place composed of a admixture of iron and nickel , peppered with silicate quartz glass . It was long take on that meteorites such as this would offer us little insight into the magnetic history of the parent asteroid because branding iron has a high-risk “ memory , ” mean it does n’t retain magnetic signal well .
Luckily for us , these meteorite contained diminutive , unassuming particles , less than one thousandth the width of a human fuzz , of a magnetic mineral called tetrataenite . Unlike iron , this mineral is capable of maintain magnetized records for jillion of years , allow scientists to peer back in time to the early solar organization . In particular , these recording trap the magnetized signal of the accurate second when the parent asteroid ’s center form , as well as the moment it freeze , killing its magnetized field .
Using a beam of ecstasy - rays , scientist from theUniversity of Cambridgewere able to give rise a detailed look-alike of the magnetization of the tetrataenite particles , which basically allow them to “ show ” the charismatic computer memory stored within the meteorite . This provide a snapshot of the curing of the asteroid ’s swimming core , which yielded interesting insight into the history of its charismatic field .
Although core solidification did bolt down the asteroid ’s magnetic field , they found that it hung around for much recollective than in the beginning believed , lasting for as long as several hundred million years after the asteroid was forged . Furthermore , they found that the magnetised theatre of operations was sire by a similar chemical mechanism to the one that gives our planet its own magnetic playing field . As the fluid alloy nub of the asteroid cooled and started to freeze , the swirling motions of the inner nub created a long - lasting magnetic playing field , just like our planet .
Just like the asteroid , Earth ’s core is also freezing , albeit much more tardily , and has been for around a billion years . What we do n’t know is how this has affected its magnetised field , which is where this subject could ply some utilitarian perceptivity . finally , the core will freeze and the protective charismatic field of study will die , but that wo n’t happen for billions of age .
[ ViaUniversity of Cambridge , Nature , BBC News , WiredandWashington Post ]
