Why Does Earth Behaves like a Magnet?
By Raktim bar
The Earth behaves like a magnet because the earth is a magnet(in a sense).But it is not permanent magnet,because permanent magnet cannot occur at temperatures above about 650 degree Celsius(1200 degree Farenhite)when the thermal motion of atoms becomes too vigorous to maintain the ordered orientations needed for parmannt magnetization.The core of the earth has a temperature of several thousand degree Celsius and hence,is not permanently magnetized.(USGS)
But The matter of that The Earth is a ‘Big Magnet’ Who discovered it?
Ans:According to gns.cri.nz,Also in this century,Georg Hartmann and Robert Norman independently discovered mangnetic inclination,the angle between the magnetic field and the horizontal.Then in 1600 William Gillbert published Demagnet,in which he concluded that the Earth behaves like a Giant Magnet.
n But if we ask that what is DeMagnet?
Ans: De Magnete consists of six books.
Book 1
Historical survey of magnetism and theory of Earth's magnetism. The loadstone in antiquity from Plato onwards and the gradual identification of iron ores. The south pole of a loadstone points to the north pole of the Earth and vice versa as the terrestrial globe is magnetic.
Book 2
Versorium
Distinction between electricity and magnetism. An amber stick when rubbed affects a rotating needle made of any type of metal (a versorium) and attracts paper, leaves and even water. But electricity is different from heat and to magnetism which only attracts iron-bearing materials (he calls it coition). He shows the effects of cutting a spherical loadstone (which he calls a terrella) through the poles and equator and the direction of attraction at different points. Magnets act at a distance but the force has no permanent presence and is not hindered like light. Materials including gold, silver and diamonds are not affected by magnets, nor can one produce perpetual motion.
Book 3
Cutting a terrella
The Earth's normal magnetism. He proposes (incorrectly) that the angle of the ecliptic and precession of the equinoxes are caused by magnetism. A loadstone cut out of rock and floated in water returns to the same direction. Iron heated to white heat and cooled lying along a meridian also acquires magnetism. But stroking with other materials fails—he proved this with an experiment with 75 diamonds in front of witnesses. The best way to magnetize a compass (magnetized versorium).
Book 4
Declination. The compass does not always point to true north. There is considerable variation. Using the terrella he shows that variations in the height of the surface can lead to differences but insists that variation is a global issue. In the midst of the ocean or continent there is no variation. He shows how to measure variation and the sources of common errors.
Book 5
Angles of force on the terrella
Magnetic dip. The angle of inclination (dip) of a compass to the horizon differs according to latitude. He shows how to construct a dip instrument. At the equator it is level and increases towards the poles as he has shown earlier with his terrella.
Book 6
Terrestrial rotation. Heraclides and others held that the Earth rotates from west to east and this is supported by Copernicus (the "restorer of astronomy"), but Aristotle said otherwise. "If the rotations of the earth seems headlong and not to be permitted by nature because of its rapidity, then worse than insane, both as regards itself and the whole universe is the motion of the primum mobile." He rejects the idea of a sphere of the fixed stars for which no proof has been offered and leaves aside the question of other movements of the Earth but "infers not with mere probability, but with certainty the diurnal revolution of the earth." He states that "the cause of the diurnal motion are to be found in the magnetic energy and the alliance of bodies" but offers no further guidance. The inclination of the Earth's pole to the ecliptic produces the seasons. He explains the Precession of the equinoxes as the movement of the Earth's axis.
In Chapter III, Gilbert argues in favor of the Copernican System. He posits that due to the inordinate distance of the celestial spheres, if in fact the spheres exist at all, it is an absurd idea that they would rotate every 24 hours, as opposed to the rotation of the relatively tiny sphere of the Earth. He states, "How far away from the earth are those remotest of stars: they are beyond the reach of eye, or man's devices, or man's thought. What an absurdity is this motion (of spheres)". He also argues for the extreme variability of the distance to the various heavenly bodies and states that situated "in thinnest aether, or in the most subtle fifth essence, or in vacuity – how shall the stars keep their places in the mighty swirl of these enormous spheres composed of a substance of which no one knows aught?".(Src:Wikipedia:William Gillbert: https://en.wikipedia.org/wiki/De_Magnet
Earth is not a permananet magnet but is a magnet(in a sense) of course,it’s an ElectroMagnet.But if we ask Why?Then the matter starts:
Deep in the Earth,Molten metal(mostly iron) flows due to heat which causes convection .(The heat appears to be generated by iron condensing at the solid core)This follow tends to organize itself into pattern,just like the pattern you will see in the oil if ypu heat in a frying pan.such patterns in a flowing conductor tend to create magnetism.The same idea is used in the “dynamo”,a device that creates both electric current and magnetism from movig conductors.Commercial dynamos’s are the source of essentially all of our wall-outlet electricity.
The principle of a dynamo is this if there is a littile magnetic field ,then when a conductor moves past it,it causes current to flow which ,if the geometry is right enhances the orginal field.So it grows until the force is a large enough to modify the pattern.
The question why the magnet sometimes flips is not yet settled.It says that the flow pattern is disrupted by an instability in the material that is deposited by the flowing iron at the core mantle interface .This leads to a disruption of the dipole character of the field,which is the then restored as a pattern reestablishes.itself however it has a 50%chance of coming back in thee opposite direction.
The Earth is composed of layers having different chemical compositions and different physical properties.The Crust of the earth Has some permanent magnetization,and the earth cores generates its own magnetic field,sustaining the main part of the field we measured at the surface.So we could say the earth is therefore ,a “Magnet”
Are Earthquakes associated with variations in the geomagnetic field?
Ans:Electro magnetic variations have been observed after earthquakes ,but despite decades of work there is no convincing evidence of electro -magnetic precursors to earthquake.It’s worth acknowledging that Geo-physicists would actuallylove to demonstrate the reality of such precursors especially if they could be used for reliably predicting Earthquakes.(USGS)
Basically,we should have to know about an unknown fact which have no idea to almost people.Let’s discuss about it.
Are you know that the pole of the earth are not fixed?
Ans: Yes,the poles are shifting but we can not measure with our eye sight,Year and year past the poles are shifting but the amount of shifting is too much small like dx(small amount of changing in differentiation)But it’s true that the poles are not permanently fixed.
As we get an idea about that “in a sense”Earth behaves like a magnet,for this reason there should occur poles!Yes.
A survey of 2015,the poles of Geo-magnet at a position of North poles Latitude(86.3degree north) and Longitude(160 degree west) the distance of the area is decreased and the position of south poles Latitude(64.3degree South) and longitude(136.6 degree East) the distance of this pole is far away near about 2860Km(British Geological Survey)
Sorry for english readers the above picture language is in Bengali in English (Elsmeyer Island,Greece Fiyord)
Coclusion:In the light of the above,I discuss about the matter of that(“The Earth Behaves Like a Magnet”)I try to give you a brief description about this fact.I f I have any error on this article please comment me.and if you like to read it so please share this to your friends etc.Thank you for read it!
To prepare this article i got help from Wikipedia,USGS,NASA JPL,PHYLAB,FORBES,CSUN,and from my knowledge.
Written By Raktim Bar.
Helpful Link to you:https://www.youtube.com/watch?v=DYLQmSuqPjY
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