what is the cause of earth"s magnetism?

Answer 1

The molten iron core is like a bar magnet. However, since the core is molten, the strength and direction of the magnetic field are changing.

Answer 2

There is a big magnet, 10 deg. from True North.This sets up a magnetic field, like all permanent magnets do. The polarisation within the magnet is South to North, whereas outside it is from N. to S. When a wire with electricity is exposed earth then the effect is the production of radio waves in the form of Sine curves.

Answer 3

All magnetic objects produce invisible lines of force that extend between the poles of the object. An easy way to visualize this is to spread iron filings on a sheet of paper and place a bar magnet under the paper. The iron filings will arrange themselves around the magnet and along the magnetic field lines.

In the simplest terms, Earth can be thought of as a dipole (2-pole) magnet. Magnetic field lines radiate between Earth's north and south magnetic poles just as they do between the poles of a bar magnet. Charged particles become trapped on these field lines (just as the iron filings are trapped), forming the magnetosphere.

Earth's magnetic field lines are not as symmetrical as those of the bar magnet. The impact of the solar wind causes the lines facing sunward to compress, while the field lines facing away from the Sun stream back to form Earth's magnetotail. The magnetosphere extends into the vacuum of space from approximately 80 to 60,000 kilometers (50 to 37,280 miles) on the side toward the Sun, and trails out more than 300,000 kilometers (186,500 miles) away from the Sun.

Answer 4

The Earth acts like a great spherical magnet, in that it is surrounded by a magnetic field. This magnetic field changes both with time and with location on the Earth and resembles, in general, the field generated by a dipole magnet (i.e., a straight magnet with a north and south pole) located at the center of the Earth. The axis of the dipole is offset from the axis of the Earth's rotation by approximately 11 degrees. This means that the north and south geographic poles and the north and south magnetic poles are not located in the same place. At any point and time, the Earth's magnetic field is characterized by a direction and intensity which can be measured. Often the parameters measured are the magnetic declination, D, the horizontal intensity, H, and the vertical intensity, Z. From these these elements, all other parameters of the magnetic field can be calculated.

the magnetic field is different in different places. In fact, the magnetic field changes with both location and time and changes the way it is changing. It is so irregular that it must be measured in many places to get a satisfactory picture of its distribution. This is done using satellites, at the approximately 200 operating magnetic observatories worldwide, and at several more temporary sites. However, there are some regular features of the magnetic field. At the magnetic poles, a dip needle stands vertical (dip=90 degrees), the horizontal intensity is zero, and a compass does not show direction (D is undefined). At the north magnetic pole, the north end of the dip needle is down; at the south magnetic pole, the north end is up. At the magnetic equator the dip or inclination is zero. Unlike the Earth's geographic equator, the magnetic equator is not fixed, but slowly changes.

The geomagnetic field measured at any point on the Earth's surface is a combination of several magnetic fields generated by various sources. These fields are superimposed on and interact with each other. More than 90% of the field measured is generated INTERNAL to the planet in the Earth's outer core. This portion of the geomagnetic field is often referred to as the Main Field. The Main Field varies slowly in time and can be described by Mathematical Models such as the International Geomagnetic Reference Field (IGRF) and World Magnetic Model (WMM).

The Main Field creates a cavity in interplanetary space called the magnetosphere, where the Earth's magnetic field dominates in the magnetic field of the solar wind. The magnetosphere is shaped somewhat like a comet in response to the dynamic pressure of the solar wind. It is compressed on the side toward the sun to about 10 Earth radii and is extended tail-like on the side away from the sun to more than 100 Earth radii. The magnetosphere deflects the flow of most solar wind particles around the Earth, while the geomagnetic field lines guide charged particle motion within the magnetosphere.

The differential flow of ions and electrons inside the magnetosphere and in the ionosphere form current systems, which cause variations in the intensity of the Earth's magnetic field. These EXTERNAL currents in the ionized upper atmosphere and magnetosphere vary on a much shorter time scale than the INTERNAL Main Field and may create magnetic fields as large as 10% of the Main Field.

It is the Main Field component that is modeled by the International Geomagnetic Reference Field (IGRF) and World Magnetic Model (WMM). Other important sources are the fields arising from electrical currents flowing in the ionized upper atmosphere, and the fields induced by currents flowing within the Earth's crust. The Main Field component varies slowly in time and can be grossly described as that of a bar magnet with north and south poles deep inside the Earth and magnetic field lines that extend well out into space. The Earth's magnetic field varies both in space and time.

Answer 5

It may be due to rotation of earth about its axis. This is because every substance is made up of charged particles. Therefore, a substance rotating about an axis is equivalent to circulating currents,which are responsible for magnetisation.
In the outer layer of earth's atmosphere gases are in ionised state ,primarily on account of cosmic rays.as earth rotates strong electric currents are set up due to movement of (charged) ions.These currents might be magnetising earth
The earth's core is very hot and molten.Circulating ions in the highly conducting liquid region of the earth core could form current loops and produce a magnetic field

Answer 6

The exact source of earth's magnetism is not copletely known,but it probably involves some dynamo effect.There is athick core of radius 3500km inside the earth.The core is in molten state.It contains melted iron,nickel and othr minerals which easily conduct electric current.With the rotation of earth about its axis ,the core also rotates.this produces a circulating surface current over the core.This surface current produces earth's magnetism.

Answer 7

My research in fundamental physics has unfolded the fact that both radiation and matter including the atomic constituents: electron, proton and neutron consist of electrical, magnetic and gravitational fields. Therefore, Earth's gravitational field is also associated with electrical and magnetic fields.

M.A.Padmanabha Rao Ph.D (AIIMS)
Professor of Medical Physics,
Himalayan Institute of Medical Sciences, Jolly Grant (2001)
Head, Radiation Safety Group& Deputy Director,
Defence Laboratory (DRDO), Jodhpur, Rajasthan (1983-97)
Lecturer in Medical Physics, Department of Nuclear Medicine,
All India Institute of Medical Sciences, New Delhi, 1964-1983).
[e-mail]; Delhi Ph: 91-11-28534251

Answer 8

What we have studied about magnetism is limited. It has only physical approach. Did you ever think of mental magnetism. Two persons are attracted and what magnet is behind it. Human body is made of five matters, where the so-called science of schools teaches only about three. The doubts would increase when you study more and more.
Flesh is of earth and blood is of water, respirational needs make up by air (when solid, liquid and gas is over) temperature and mind are there which are matters made up of for creation of human body. The earth part is cycling (attracts) the earth parts of our body and air attracts the air in our body. The other cycle of transformation, which is called as growth of our human body. (Transformation is towards front and we can not be back to young age) This is the Science of individual knowledge taught individually one himself and thus the human body of earth, water and air draws back to the earth, but birds body is more of air (less earth parts - light flesh and hollow-bones) and they can fly. What weight is the force of attraction, which in Moon is less compared to earth. Magnetism is merely a part of attraction of physical body and "attraction and repulsion" are a Superior study of Magnetism.

Answer 9

Electric currents in the earth's outer core, see the reference.

Answer 10

cause of gravitational force every thing attract toward earth.it's called earth's magnetism.