Magnetic field of the Earth
Earth is a giant magnet with its south magnetic pole in the Northern Hemisphere
one pole (south) located north of Hudson Bay (Canada)
the other pole (north) located directly on the other side of Earth
strength of the magnetic field at the surface of the Earth ~ 0.5 G
magnetic axes tilted with 12 0 relative to the rotational axis
origin of the Earth’s magnetic field --> still a mystery (modern theories presume that is the result of the convection currents in melted metals in the core, but no accepted theories)
Earth’s magnetic field is a shield against high energy and charged cosmic particles
the strength of the magnetic field is varying--> momentary: decreasing
The Earth switched the poles 171 times during last 17 million years
During switching: long periods without any magnetic field--> danger to living organism.
Next disappearance of the magnetic field (prognoses) after 4000 years.