PHYSICS MADE EASY -the Earth's axis of rotation - basics
flowing Hi, this short video is only to give an understanding of the axis of Earth's Rotation about its Geographic North Pole~South Pole axis. This is tilted at an angle of 23.45 degrees , with respect to an imaginary vertical plane passing through the Earth's centre.
Another way of understanding this angle is that the earth is tilted with respect to a vertical plane which is perpendicular to a CENTRAL plane passing through the centre of sun and earth i.e. along the earth's orbit around the sun. This central plane cuts the earth along an axis which is not the equator. Because the earth is tilted at 23.45 degrees with respect to this central plane, therefore the earth's equatorial plane (passing through the equator) is also at an angle of 23.45 degrees to the central plane.
The earth's geographic poles are tilted to the sun at a CONSTANT angle.
Pl. note : The earth's Magnetic poles North-South are also tilted, in fact another 11 degrees with respect to the Geographical North-South pole axis. This difference is called "DECLINATION". and can be checked using a Compass which will always point in the Magnetic North-South direction and not to the Geographic North-South direction. In the animation, the Geographical North-South axis is shown in Red colour, whereas the Magnetic North--South axis is shown in white dotted line.
However, note that the North Magnetic Pole is near the Geographic South Pole, whereas the Magnetic South Pole is located near the Geographical North Pole. This opposite naming convention happened because scientists fixed the compass needle's end which points towards Geographic North as the North Pole of the compass, hence for the Earth that pole will be Magnetic SouthPole. The North Pole of cpmpass will be always attracted to the South Pole of "Earth as a bar magnet"
Compass needle behaviour at the poles: At the earth's Magnetic South Pole, the north pole of compass will dip downwards by 90 degrees. This is called "DIP"
The Magnetic North-South poles behave as if there is a GIANT BAR MAGNET inside the earth, but there is no such bar nagnet in reality. Actually, the magnetism is created by complex electric currents due to the molten IRON in the Earth's core. The electric current flows create a Magnet effect due to electromagnetism phenomenon.
The Earth's Magnetic Field surrounds the earth for more than 10,000 km, and it is our shield, it protects the Earth's living creaturs and flora/fauna from the harsh Solar Storms coming from the Sun. If we did not have this Magnetic Field, all our atmosphere would have got finished long back. Scientists found by experiments that this is exactly the tragedy that heppened to the atmosphere of Mars!
best regards
kaustubhan
