THE EARTH The earth is the largest terrestrial planet in our Solar System. It revolves around the Sun in a year and rotates about its axis at every 24 hours. DATA ABOUT THE EARTH Equatorial diameter 12 756 km Average distance from 1.496 x 108 km (1 AU) the Sun Inclination of equator 0ᵒ to ecliptic Inclination of equator 23ᵒ 17’ to orbit Orbital Period 365.256 days (1 yr) Period of rotation 23 hr. 56 min. 4.1 s Average orbital velocity 29.8 km/s Mass 5.98 x 1 024 kg Average density 5.5 g/cm Surface Gravity 9.8 m/s Escape velocity 11.2 km/s Surface temperature -50 to 50ᵒ C EARTH’S INTERIOR 1.Core – is composed of iron and nickel and is about 55 percent of the diameter of the earth in size. Outer core Is about 2100 km thick. It makes up about 30 % of the Earths total mass. Inner coreIs about 1300 km thick. It makes up about 2 % of the Earths total mass. 2. Mantle – is the layer of dense rock and metal oxides. It lies between the core and the Earth’s crust. 3. Crust – is thin and rocky. Its thickness is about 70 km under the ocean. THE EARTH’S MAGNETIC FIELD dynamo effect- the best current theory of the origin of the magnetic fields. It supposes that the liquid part of the core is stirred by the presence of convection currents solar wind- is a gas of rapidly moving atoms and ions that escape from the Sun and move through the Solar System.
Posted on: Thu, 03 Jul 2014 03:36:52 +0000
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