Image: Earth
Image Credit: Encarta Encyclopedia
Earth, the home of the only known life that we know of, and even
though after 4.6 years since its birthday, Earth still continues to change.
It is the third from the sun, and is actually not a perfect sphere.
Because of the pull at the poles, the earth bulges somewhat at them, making
it more of a pear shape than sphere. It takes it one year to complete
its orbit around the sun, and 23 hours 56 minutes and 4.1 seconds to rotate
on its axis.
Earth consists of five parts: atmosphere(gaseous),
hydrosphere(oceans) lithosphere, mantle, and core. The mass of the
hydrosphere is 1.35 X 108 and covers two thirds of the
world. The mantle and the core make up most of the rest of the mass.
The lithsophere is divided up into two shells: crust and upper mantle.
Earth also has an internal heat source, thought to come from the core.
It is believed the heat comes from radioactive decay of uranium and other
radioactive elements.
Image: Earth
Image Credit: Gods and
Goddesses
Originally, the Earth was homogenous and had
a rather cool temperature. Yet because of contractions, heat was
produced. It became so hot because of gravitational pulls,
that the substances began melting, and finally differentiated into the
crust, mantle, and core. The atmosphere was created from gases that
escaped from erupting volcanoes. The earth eventually turned into
what is known as Primordial Soup, which was a very harsh environment with
many deadly elements in the air. The oceans were as giant hot baths,
boiling from underwater volcanoes. Eventually though, this all stopped
and the earth began to cool down, and the atmosphere gradually changed
into what it is now.
The Earth acts as a giant magnet,
and it has two poles. The north pole is at hte western coast of Bathurst
Island in Canadian Northwestern Territories, and the south pole is at the
edge of the Antarctic continent in Adelie Land. Yet, one of the more
strange things about the poles is that they change position every year.
There are also three electrical current systems on Earth: atmosphere, inner
earth, and earth to atmosphere. The atmosphere currents are caused
by atmosphere ionization by solar radiation and movement of ion clouds.
Inner earth consists of eight current loops evenly distributed over Earth.
In the core, there is molten iron and nickel, which act as electric conductors.
So the loops are formed from other currents pushing the nickel and iron.
The electrical current from earth to atmosphere, also called the surface
charge, is probably one of the more common known ones. It happens
mostly during Storms. The Earth has a negative surface charge, and
if it were not replenished, the negative charge would disappear.
During fair weather, there is a constant influx of positive charge, but
during a storm, a huge amount of negative charge will be deposited on the
Earths surface. It is thought that the constant positive charge downwards
from everyday, will balance out the natural negative charge, and the charge
deposited by storms.
Click here to go back.
Last Updated
August 28, 1998.
All images,
unless otherwise credited, are credit of M. Mathis, 1998.