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The picture of an atom , with electrons teem around a cardinal nucleus bulge with proton and neutrons , is as iconic in our percept of science as the DNA helix or the rings of Saturn . But however much we strike the surface of these scientific fundamentals , we can go even profoundly , focusing that microscope further and discover even more force that govern our worldly concern .
In his fresh Word " billing : Why Does Gravity Rule ? " , theoretical physicistFrank Closeexplores the fundamental forces that govern our world , lay questions along the way that assay to excuse how the delicate balance of positive and negatively charged commission paved the fashion for gravity to shape our universe .
“Today, the Earth’s liquid core is still a terpsichorean frenzy of electric currents, which generate a magnetic field."
In this excerpt , he explains how magnetism , the most tangible central force , was identify , where it get from and how it scram its name .
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The force within
magnetic attraction is a manifestation of electricity , and vice versa . Electricity and magnetism were imprint into our milieu from the source . Five billion age ago when the new - bear Earth was a hot plasma of swirl electrical currents , these flows create magnetic fields . As the magma cooled to take shape what is today the world ’s solid out impudence , magnetismwas lock up into minerals containing atomic number 26 , such as magnetite .
Today , theEarth ’s limpid coreis still a terpsichorean frenzy of galvanizing currents , which bring forth a magnetic field . This extend into the air and far beyond , unseeable to our normal senses . But in spreading from its source in the liquified core to the heavens above , it first permeates the Earth ’s encrustation . This is where it provide a palpable embossment , grounds that there be a force play more herculean than graveness at work within the Earth whose influence extends very far .
Way back in the earliest Precambrian , four billion years ago , as the control surface cool down , nuclear element pile up in the strata . The most stable of these , iron , is today one of the most abundant element in the crust . fiery Rock formed from volcanic lava . These rock and roll have the property that in the comportment of a magnetic field of operations , their mote of smoothing iron act like soldiers on parade as they themselves become charismatic . This is exploited in democratic monstrance where the magnetic field of a bar magnet can be made seeable .
Magnetic field. A bar magnet induces magnetism in pieces of iron, revealing the presence of its magnetic field spreading from one pole to the other.
Small filing of iron are first spread out on the airfoil of a table and then a magnet is placed carefully among them . Its magnetic field induces magnetism in the iron filing , turning them into thousands of miniature magnet . Each of these punctually orient itself in the magnetic field , let out how the direction of the magnetic military group varies from place to place .
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The bar attractive feature is a simple model illustrating what happens for the magnetic Earth itself . Earth ’s magnetic north and south magnetic polesare analogous to those of the cake magnet , our planet ’s magnetised field extending far into space . There are no atomic number 26 filing out in outer space , but there are gravid measure of branding iron ores in the hills , cliff , and quite a little on Earth . In some place , by probability , these magnetized bunch are quite all-encompassing , as on the Isle of Elba and Mount Ida in Asia Minor , where large outcrops retain the magnetic imprint in rock candy cognise historically as lodestone , now named magnetite .
There are legend how thousand of age ago in ancient Greece , a sheepherder wearing leather shoes held in shoes by iron nails stumbled — literally — across magnetite when the powerful magnetism gripped the nail in his footwear . Whether or not a shepherd named Magnes discovered the eponymic rock , and if so whether it was in Magnesia , north of Athens , or on Mount Ida in Asia Minor , or even another Mount Ida in Crete , it is very likely that such experiences , if less striking than in the story , would have happened on various occasions .
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Certainly , the power of magnetic attraction would have been apparent ever since the Iron Age . Lightning is a flash of electric current which bring forth intense magnetic plain and mesmerize ferrous rocks . Smelting to retrieve the pure iron metal from these sources would have give away their magnetised attractiveness . So , the phenomenon has belike been known for some 3,000 years . Like the breakthrough of fire , that of magnetism probably arose in several seat independently , all urge by the instinctive magnetization of iron in rocks .
For magnetic rock’n’roll are omnipresent . By the sixteenth century traveller immortalise the best instance , from East India and the Taiwanese sea-coast : " Very massive and corpulent , [ the Isidor Feinstein Stone ] will draw or lift up the just weight of itself in branding iron or blade " [ Robert Norman , The Newe Attractive , 1581 ] . As knowledge of the phenomenon spread from Hellenic myth to Latin , and on to English , the names morphed into ' Magnes rock-and-roll ' or ' attraction ' .
© [ Oxford University Press ]
selection from thrill : Why Does Gravity Rule ? by Frank Close , published by Oxford University Press , available in hardback and eBook formats
bursting charge : Why Does Gravity Rule ? by Frank Close — $ 21.99 on Amazon
If you savor this extract , the sleep of the script builds on this brief history of magnetism and delves ever deeply into the subatomic world to explore the cardinal questions of physics . It ’s complex stuff , but esteemed theoretic physicist Frank Close guide you through the issue with lucidness , making for a highly enjoyable read . We specially delight the surgical incision about the search for proton decay , which required the fill of an hugger-mugger pond with 8,000 tonnes of purified piddle — doubly .
— Read our interview with Frank Close
