The Planet Earth

go to www.greenpeace.org.uk/ and TAKE ACTION if you can !!!!!The Planet Earth is the third planet away from the Sun, and is the fifth largest planet in the solar system. It is also the largest of its planetary system's terrestrial planets, making it the largest solid body in the solar system, and it is the only place in the universe known to humans to support life. It is also the densest planet in the solar system. Widely accepted scientific evidence indicates that the Earth was formed around 4.57 billion years ago and its natural satellite, the Moon, was orbiting it shortly thereafter, around 4.53 billion years ago. The outer surface is divided into several tectonic plates that gradually migrate across the surface over geologic time spans. The interior of the planet remains active, with a thick layer of convecting yet solid mantle and an iron core that generates a magnetic field. Its atmospheric conditions have been significantly altered by the presence of life forms, which create an ecological balance that modifies the surface conditions. About 71% of the surface is covered in salt-water oceans, and the remainder consists of continents and islands. There is significant interaction between the Earth and its space environment. The relatively large moon provides ocean tides and has gradually modified the length of the planet's rotation period. A cometary bombardment during the early history of the planet is believed to have played a role in the formation of the oceans. Later, asteroid impacts are understood to have caused significant changes to the surface environment. Long term periodic changes in the orbit of the planet may also be responsible for the ice ages that have covered significant portions of the surface in glacial sheets.A IMG{ border-style:none;