How the earth's magnetic field is measured?
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With a Magnetometer. See below for more detail.
1092387
The closest magnetic source.
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Well, technically, it is the Earth's Core.  But if you're referring to MAN-MADE magnets, you are typically looking at superconducting magnets.\n\nRight now, it seems like the two contenders are superconductors at MIT and in Japan.\n\n\nThis may be the next contender:\n\nhttp://www.research.fsu.edu/researchr/springsummer99/departments/abstracts/BiggestMagnet.html
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The human body is not capable of being made magnetic.  It shows virtually no response to magnetic fields as high as 3 Tesla and more--and as a reference, the magnetic field of the earth is 0.0005 Tesla...\n\nA sufficiently intense magnetic field COULD levitate the human body, though--it's been done with bugs and frogs, without any perceptable injury or even awareness of the field.
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Earth\n\n In our Solar System , planet Earth is the third in distance from the Sun and the fifth largest in diameter. The mean distance of the Earth from the Sun is 149,503,000 km, and radius varies from 6378 km in the equator to 6356 km in polar direction. It is the only planet known to support (intelligent) life, although some of the other planets have atmospheres and contain water (it has been shown lately that there could have been some life in ancient Mars!)\nFor the space physicist, the most important aspect of the Earth is that it behaves as an enormous magnet. The English physician and natural philosopher William Gilbert was the first to demonstrate this similarity in about 1600, although the effects of terrestrial magnetism had been utilized much earlier in primitive compasses. In first order the magnetic field created by this magnet is that of a dipole whose axis is tilted with respect to the spin axis by about 11 degrees. The north magnetic pole is presently located off the western coast of Bathurst Island, in the Canadian Northwest Territories, almost 1290 km northwest of Hudson Bay. The south magnetic pole is presently situated at the edge of the Antarctic continent in Adélie Land about 1930 km northeast of Little America. The magnetic field points down towards the surface of the Earth in the northern hemisphere, and away from it in the southern hemisphere. The difference between the dipole axis and geographic axis is one of the reasons why there are so many different coordinate systems needed to describe locations in space around the Earth.\n\nThe area around the Earth governed by its magnetic field is called the magnetosphere . The properties of the magnetosphere are strongly affected by the solar wind . The interaction between the solar wind and the magnetosphere is important in space physics.
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South Magnetic Pole\nIs the point on the Earth's surface where the direction of the Earth's magnetic field is vertically upwards. The magnetic dip, the angle between the horizontal plane and the Earth's magnetic field lines, is 90° at the magnetic poles. The south magnetic pole is not fixed and its position moves about 5 kilometres a year presently in a north to northwesterly direction. The location of the south magnetic pole as at February 1998 was 64.59° S and 138.53° E.\n\nGeomagnetic Pole\nEither of two points of intersection of the surface of the Earth with the extended axis of a magnetic dipole which is assumed to be located at the centre of the Earth and approximates the source of the Earth's magnetic field. It should not be confused with the magnetic pole which relates to the actual magnetic field of the Earth. The south geomagnetic pole is at 78° 30' S and 111° E which is near Russia’s Vostok Station.
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The pole in the north direction of earth is the south magnetic pole of earth's magnet.\n\nThe position of magnetic pole is changing but not the pole itself. If the pole cahnges then the magnetic needle in the compass will deflect in the opposite direction.
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Above the line, the directon is north\n\nBelow the line, the direction is south.\n\nI think.  From what i remember, you use the right-hand rule.  Imagine pointing your right thumb toward west.  Your four fingers, will indicate the direction of the magnetic field.
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My favourite is the test done to prove the magnetic force of earth.  I do not remember who the scientist was but in the dome of St. Pauls's Cathedral in London UK, he suspended a rope from the highest point down to the ground where he had a level patch of sand.  A weighted point on the rope was just about able to touch the sand.  Sure enough, as time went on the rope began to move with the direction of the earth leaving evidence of stripes in the sand.
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There is a confusion about magnetic attration and gravity attraction. First of all,nothing has been proven to show that there is something in the earth that pulls you down.It makes more senseto believe that gravity is an external phenomena rather than an internal one.\n\nThere is no magnetic response unless two poles exist in a material. In this case we have an internal phenomena which has to do the atomic structure of the material which forms\nan external circuit of twisted space. It requires two opposite ends to observe a magnetic response. The poles of a material which is magnetized can exhibit both attraction and repulsion.\nMost material display some magnetism.\nFerrous material are able to store magnetic power more so than other material because of the arrangement of their electronic structures.\n\nIt is believed by scientists that  the magnetism of the earth is caused by a molted iron core;however ,it has\nbeen shown that at high temperature a magnetic field cannot be established.\n\nThe best explanation presented was that the earth magnetic field is caused by the motion of the ocean around the earth.
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If you mean the earth having a magnetic field, then the main way is that it takes fatal amounts of solar radiation and deflects it around our planet and off into space.  If you live far north or far south you can see the solar particles being deflected.  It's called aurora or the northern/southern lights.
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I answered your question already.  Magnetic field strength is governed by amount of current flow.
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Only 70% of the power flux reaches the surface ot the earth.\nThe electric field is defined a Newton per unit charge..\nThe power flux from the sun is really radiation power its Usually measured in Joules per second per meter^2. \nVolt per meter is = to force per unit distance. Its resulting units are kg /sec^2. which is not equal to joules/sec/meter^2.
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No.The magnetosphere is the result of Earth`s magnetic field. It depends directly on the magnetic field. But is not expanding or getting smaller, at least not at a large scale. There are variations, but little ones. The magnetic field is created by Earth`s spinning melted iron core. If the angular speed of the core decreases or increases, then the magnetic field and the magnetosphere will do the same thing. For now, thank`s God, is constant.
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We do not really understand what causes the earth's magnetic field, but presumably it is caused by electric currents flowing in the earth, possibly as charged pieces of molten metal move around in the outer core. \n\nSo in this way, the earth's field is due to something more like an electromagnet, which is not destroyed by heat, instead of a permanent magnet, which is destroyed by heat.
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Earth's magnetic field is fading. Today it is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss started keeping tabs on it in 1845, scientists say. \n\nIf the trend continues, the field may collapse altogether and then reverse. Compasses would point south instead of north.
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IF YOU DON'T UNDERSTAND MY ANSWER.....FOLLOW THIS LINK ;\n\nhttp://en.wikipedia.org/wiki/Dipole\n\nA dipole (Greek: di(s) = double and polos = pivot) is a pair of electric charges or magnetic poles of equal magnitude but opposite polarity (opposite electronic charges), separated by some, usually small, distance. Dipoles can be characterized by their DIPOLE MOMENT : A VECTOR QUANTITY WITH A MAGNITUDE EQUAL TO THE PRODUCT OF THE CHARGE OR MAGNETIC STRENGTH OF ONE OF THE POLES AND THE DISTANCE SEPARATING THE TWO POLES. The direction of the dipole moment corresponds, for electric dipoles, to the direction from the negative to the positive charge. For magnetic dipoles, the dipole moment points from the magnetic south to the magnetic north pole — confusingly, the "north" and "south" convention for magnetic dipoles is the opposite of that used to describe the Earth's geographic and magnetic poles, so that the Earth's geomagnetic north pole is the south pole of its dipole moment. Because of the absence of magnetic monopoles, magnetic dipoles are actually created by current loops or by quantum-mechanical spin.\n\nSince the direction of an electric field is defined as the direction of the force on a positive charge, electric field lines point away from a positive charge and toward a negative charge.\n\nWhen placed in an electric or magnetic field, equal but opposite forces arise on each side of the dipole creating a torque τ:\n\nτ = p x E  (for an electric dipole moment p) (measured in coulomb-meters)\n\nor\n\nτ = m x B = u0m x H  (for a magnetic dipole moment m) (measured in ampere-square meters).\n\nThe resulting torque will tend to align the dipole with the applied field.