|Star System Sol - Planet Earth: The Blue Planet
Earth is also called the blue planet because 74% of its surface is covered by water. Water is essential to all life on
Earth and is the most abundant liquid found on Earth. Earth is teeming with a rich variety of life, indeed wherever
there is liquid water life exists on Earth - from ice fish which live in the cold Southern Ocean and have a body
temperature of about minus two degrees C (some algae live in Antarctic rocks at -15 degrees C), to heat-loving
bacteria that thrive in temperatures in excess of 100 degrees C (the current record holder thrives at 121 degrees C)
near volcanic vents on the sea floor. From bacteria that thrive in atmospheric clouds to bacteria that live two miles
underground inside rocks. From microscopic plankton that float on the sea's surface, to bizarre life-forms that live
more than 11 000 metres beneath the ocean's surface, in the deepest trenches, at pressures in excess of 1100
The following links are still under development, but discuss life on Earth in more depth. Where would you like
to go now?
|Click on the oak tree to learn about life on Earth in the Bio/Nature Tech section.
|Major Tourist Attractions
The Earth's oceans are teeming with life. Take a deep sea voyage to the Abyssal and Hadal depths or see
the native giants: whales, giant jellyfish and giant squid.
Forests and woodlands
See the beautiful, but rapidly disappearing, forests of the Earth, while they last! (Be quick!).
Marvel or despair at the site of enormous cities rife in crime, inner city poverty, inequity and deprivation.
Understanding city development and growth is a major subject of scientific study in the social sciences and
the Earth is a classic example of the problems that arise in primitive cities. See cities for more.
Planet type: large terrestrial, oceanic
Equatorial Radius: 6378 km
Equatorial Diameter: 12 756 km
Orbit: the Earth orbits Sol at an average distance of 149 597 870 km once every 365.25 days and rotates on its own
axis once every 24 hours.
Atmosphere: a mixture of gases called air (78% nitrogen, 21% oxygen, 0.9% argon, 0.033% carbon dioxide,
variable amounts of water vapour and traces of other gases, % given by volume). Pressure at surface is
about one atmosphere (101,325 Pa). Consists of the lower troposphere which contains the weather and
ends at the jet stream and tropopause at 10 km, followed by the stratosphere which contains some
ice-clouds and ends at 50 km above the surface at the ozone layer and stratopause, followed by the
mesophere which ends at the mesopause at an altitude of 80 km, followed by the thin thermosphere. The
ionosphere extends from 50 to 300-400 km and includes the mesosphere and thermosphere. The
thermosphere extends to 800 km and is followed by the exosphere which extends to 1600 km and consists of
ionised atomic hydrogen and helium.
Surface Temperature: average 15 degrees C.
Magnetic Field: strong, extends tens of thousands of km into space as the magnetosphere.
Natural Satellite: Moon (a secondary planet).
See also the internal structure of the Earth.
|Click on the image below to learn about the
structure and composition of the Earth:
Click on the image below to explore the
scientific principles behind Earth's
cities - their location, growth, structure