Protects the planet from huge blasts of deadly solar radiation, has been weakening over the past six months, according to data collected by a European Space Agency (ESA) satellite array called Swarm.
The Earth's magnetic field is similar to that of a bar magnet tilted 11 degrees from the spin axis of the Earth. The problem with that picture is that the Curie temperature of iron is about 770 C. The magnetic field of the Earth is fairly weak on the surface. After all, the planet Earth is almost 8,000 miles in diameter, so the magnetic field has to travel a long way to affect your compass. That is why a compass needs to have a lightweight magnet and a frictionless bearing. Let’s take a look at the Earth’s magnetic field. The Earth is like a great big magnet. The north pole of the magnet is near the top of the planet, near the geographic north pole, and the south pole is near the geographic south pole. Magnetic field lines extend from these poles for tens of thousands of kilometers into space; this is the Earth’s magneto sphere. Dangerous particles don't hit the Earth's surface because they are forced by the magnetic field to move around the Earth. Particles do enter at the funnels over the poles or they gain entry far downstream from the Earth. The particles that enter downstream or at the magnetotail cause the auroral lights. The Earth has a magnetic field with north and south poles. The Earth's magnetic field reaches 36,000 miles into space. The magnetic field of the Earth is surrounded in a region called the magnetosphere. It does seem clear that the generation of the magnetic field is linked to the rotation of the earth, since Venus with a similar iron-core composition but a 243 Earth-day rotation period does not have a measurable magnetic field. Earth's magnetic field, which protects the planet from huge blasts of deadly solar radiation, has been weakening over the past six months, according to data collected by a European Space Agency (ESA) satellite array called Swarm. A compass works the way it does because Earth has a magnetic field that looks a lot like the one in a magnet. The Earth's field is completely invisible, but it can be felt by a compass needle on the Earth's surface, and it reaches thousands of miles out into space. Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth 's interior to where it meets the solar wind, a stream of charged particles emanating from the Sun.
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/MagEarth.html http://adventure.howstuffworks.com/outdoor-activities/hiking/compass1.htm http://www.universetoday.com/27005/earths-magnetic-field/ http://www.windows2universe.org/glossary/plasmaspheric_gain.html http://www.windows2universe.org/glossary/plasmaspheric_gain.html http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/MagEarth.html http://www.scientificamerican.com/article/earth-s-magnetic-field-flip-could-happen-sooner-than-expected/ http://image.gsfc.nasa.gov/poetry/magnetism/magnetism.html https://en.wikipedia.org/wiki/Earth%27s_magnetic_field
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