Earth – the third planet from the Sun is exceptional in the Solar System for many reasons. It is the only planet presently known to support life. It is also the only one with large amounts of liquid water on its surface...
    However, the Earth's internal structure is very similar to other planets in the inner part of our planetary system. At its center there is a heavy core of iron and nickel consisting of an inner solid part and the outer liquid one which is where the magnetic field is generated. You may read more about the Earth's magnetic field at a very interesting webpage by Zbigniew Suchowski... Above the core there is a mantle of much lighter silicate rocks with a solid but malleable consistency. The mantle is covered with a thin crust of solid rock. The crust itself is unusual in being divided into separate plates slowly moving with respect to each other constantly changing the arrangement of land masses. The Earth is also exceptional in having a pretty large natural satellite with respect to its own size.
    Apart from the differences the Earth has got a lot in common with other planets. It has vulcanic activity like Jupiter's moon Io or Neptune's – Triton. It also has impact craters like all the other bodies in the Solar System although most of them have been erased due to erosion and other factors. Many other bodies in the Solar System are also known to have surface features found on Earth like mountain chains or canyons.

    The Earth as seen from space (see photo) is a beatiful view of blue seas, brown continents with some green from the plants and white clouds. No other planet is so picteresque in that perspective! Since the Earth is massive enough it will be able to keep its atmosphere (with present composition: 78% N₂, 21% O₂ and 1% ther gases with the neighbouring planets' atmospheres consisting mainly of CO₂). Due to the heat received directly from the Sun or reflected off the masses of land and water the Earth's atmosphere is constantly in motion forming a complicated system of wind circulation. All the water covering 71% ist surface is also moving constantly. The land masses are also subject to continuous change being affected by such factors as the atmosphere and hydrosphere and also the already mentioned movements in the Earth's crust..
    Therefore the whole Earth can be called a "living planet" since not only the spirited matter but also the uspirited is subject to constant change and evolution....

THE ROTATING MAP OF EARTH

The source data to the map:
The texture

 
THE ORBIT OF EARTH

    The Earth is in an elliptical heliocentris orbit of →eccentricity e = 0.017 and a →semimajor axis a = 149,597,890 km (so about 149.6 million kilometers). This distance is used in astronomy as one of the basic distance units, called the →astronomical unit – AU.
    At perihelion (closest to the Sun) on the 3rd of January the Earth is at a distance of 147,098,076 km (0.98 AU). Then it is moving with its maximum orbital velocity of 30.8 km/sec. The angular size of the Sun's disk is 0°32'31''.
    At aphelion (furthest from the Sun) on the 4th of July it is at a distance of 152,097,704 km (1.02 AU). The Earth's velocity is then lower by 1 km/sec and the angular size of the Sun's disk is 0°31'27''. Please note that the disks of the Sun and the Moon are very similar in size! This similarity comes from the Sun being roughly 400 times bigger than the Moon and the Moon being 400 times closer than the Sun. Laser ranging experiments have shown that the moon is moving away from the Earth by 4 centimeters a year which means that in the future this similarity will unfortunately seize to exist with the Moon being visibly "smaller" than the Sun...
    We are fortunate not to have the Earth's orbit being subjected to much change thus not affecting the Sun's visible brightness (constantly about –26.7^m). This is one of the conditions that must have been met for life to survive and develop!
    It is also worth to remember that the plane of the Earth's orbit is called the →ecliptic and is used as reference for calculating the inclination of planetary orbits and those of other bodies in the Solar System...

    That conludes this brief description of the Earth since the main theme of my Web page is planetary satellites and not planets themselves. If you would like to find out more about the Earth you can visit other Web pages devoted only to this planet! Below the table there are a few links which may be a starting point in your journey through Cyberspace...