LOOKING-AT-EARTH

LOOKING AT EARTH 

Our planet is far from smooth-its continents and ocean floors are scarred and pitted with marks caused by plate movement. Earth’s place in space also affects its shape, as constantly spinning makes it bulge out around the middle instead of forming a sphere. Spinning also creates a magnetic safety field around the planet.

A spinning planet 

Earth’s gravity would pull it into the shape of a sphere,but its rotation makes it bulge slightly. This means its diameter at the equator is 41 km (25 miles) more than the distance between its polees.NOT QUITE ROUND –At the moment,scientists think that Earth’s equatorial buleg is growing at a rate of 7mm(0.3 in) every 10 years.

Magnetic Earth 

Because Earth’s outer core is liquid, the planet’s rotation stirs it into motion.This motion causes electric currents to develop in the liquid iron itself.Any pattern of electric currents creats a magnetic field,and in Earth’s case, the field is similar to what would be produced by a large bar magnet inside the planet. The field protects Earth from damage by harmful, energetic particles that come from the Sun. THE MAGENETIC FIELD-The magnetic poles do not coincide exactly with the geographic (rotational) poles,and they gradually change position over time.

Earth’s surface 

The solid surface of the Earth ranges from about 10,900 m (35,750 ft) below sea level in the Challenger Deep (part of the pacific’s Mariana trench) to 8,848 m (29,029 ft) above sea level at the summit of everest, which may be rising at about 4mm (0.16 in)per year. The surface of most land areas is less than 500m(1,650 ft) above sea level.