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Documentary: National Geographic / Naked Science / Earth's invisible shield
Earth, born of fire
Guide planets in our Solar System
Source
video
http://www.dondocumentales.com/2011/04/ciencia-al-desnudo-tierra-magnetica.html Publish Post
Documentary: National Geographic / Naked Science / Earth's invisible shield
At the core of our planet there is a ball of solid iron at a temperature approximately equal to the Sun's surface . The researchers call the "inner core." It really is a world inside another world. The inner core has a size of 70% of the Moon. Touring with natural period, 0.2 degrees of longitude per year faster than the Earth's surface, and has its own ocean: a very deep layer of liquid iron known as the outer core. "
The Earth's magnetic field originates in this ocean of iron, an electrically conducting fluid in constant motion. Resting on the hot inner core, outer core liquid is stirred furious. The outer core is also suffering from "hurricane", eddies generated by Coriolis forces caused by Earth's rotation. These complex motions generate our planet's magnetism through a process called "Dynamo effect." The changes we detected in the planet's surface are a sign of the chaos inside.
The magnetic field increases and decreases, the poles are moving, occasionally alternate. Sometimes completely reversed field. The north and south pole exchange their positions. Such investments recorded in the magnetism of ancient rocks, are unpredictable. Occur at irregular intervals, about once every 300,000 years, the last one took place 780,000 years ago. "Approaching a new change? Nobody knows.
An investment in the magnetic polarity takes a few thousands of years to complete and during that time the magnetic field disappears. The magnetic lines of force near Earth's surface curl and entangle and magnetic poles appear unexpectedly in unaccustomed places. The south magnetic pole might emerge in Africa, for example, or the North Pole could arise in Tahiti. Yet, it remains a planetary magnetic field, and still protecting us from space radiation and solar storms .
The magnetic north pole of Earth, for now, is located in northern Canada , about 600 km away from the nearest town: Resolute Bay. Source
Information: http://ciencia.nasa.gov/science-at-nasa/2003/29dec_magneticfield/
Earth, born of fire
Guide planets in our Solar System
Source
video
http://www.dondocumentales.com/2011/04/ciencia-al-desnudo-tierra-magnetica.html Publish Post
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