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Earth
Last update: Saturday 31st of July 2010
 Famous "Blue Marble" photograph of the Earth, taken from Apollo 17. | ||||||||||
| Orbital characteristics | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Epoch J2000 | ||||||||||
| Aphelion distance: | 152,097,701 km (1.016 710 333 5 AU) 94,509,130 miles | |||||||||
| Perihelion distance: | 147,098,074 km (0.983 289 891 2 AU) 91,402,725 miles | |||||||||
| Semi-major axis: | 149,597,887.5 km (1.000 000 112 4 AU) 92,956,041 miles | |||||||||
| Semi-minor axis: | 149,576,999.826 km (0.999 860 486 9 AU) 92,943,062 miles | |||||||||
| Orbital circumference: | 924,375,700 km ( 6.179 069 900 7 AU) | |||||||||
| Eccentricity: | 0.016 710 219 | |||||||||
| Sidereal period: | 365.256 366 day (1.000 017 5 yr) | |||||||||
| Avg. orbital speed: | 29.783 km/s (107,218 km/h) | |||||||||
| Max. orbital speed: | 30.287 km/s (109,033 km/h) | |||||||||
| Min. orbital speed: | 29.291 km/s (105,448 km/h) | |||||||||
| Inclination: | 0 (7.25° to Sun's equator) | |||||||||
| Longitude of ascending node: | 348.739 36° | |||||||||
| Argument of perihelion: | 114.207 83° | |||||||||
| Satellites: | 1 (the Moon) | |||||||||
| Physical characteristics | ||||||||||
| Ellipticity: | 0.003 352 9 | |||||||||
| Mean radius: | 6,372.797 km | |||||||||
| Equatorial radius: | 6,378.137 km | |||||||||
| Polar radius: | 6,356.752 km | |||||||||
| Aspect Ratio: | 0.996 647 1 | |||||||||
| Equatorial circumference: | 40,075.02 km | |||||||||
| Meridional circumference: | 40,007.86 km | |||||||||
| Mean circumference: | 40,041.47 km | |||||||||
| Surface area: | 510,065,600 km² | |||||||||
| Land area: | 148,939,100 km² (29.2 %) | |||||||||
| Water area: | 361,126,400 km² (70.8 %) | |||||||||
| Volume: | 1.083 207 3×1012 km³ | |||||||||
| Mass: | 5.9736×1024 kg | |||||||||
| Mean density: | 5,515.3 kg/m³ | |||||||||
| Equatorial surface gravity: | 9.780 1 m/s² (0.997 32 g) | |||||||||
| Escape velocity: | 11.186 km/s (≅39,600 km/h) | |||||||||
| Sidereal rotation period: | 0.997 258 d (23.934 h) | |||||||||
| Rotation velocity at equator: | 465.11 m/s | |||||||||
| Axial tilt: | 23.439 281° | |||||||||
| Right ascension of North pole: | undefined° | |||||||||
| Declination: | +90° | |||||||||
| Albedo: | 0.367 | |||||||||
| Surface temp.: Kelvin Celsius |
| |||||||||
| Adjectives: | Terrestrial, Terran, Telluric, Tellurian, Earthly | |||||||||
| Atmosphere | ||||||||||
| Surface pressure: | 101.3 kPa (MSL) | |||||||||
| Composition: | 78.08% N2 20.95% O2 0.93% Argon 0.038% Carbon dioxide Trace water vapor (varies with climate) | |||||||||
Earth (IPA: , IPA: ) is the third planet from the Sun and is the largest of the terrestrial planets. Earth is also referred to as "the Earth", "Planet Earth", "Terra", or "the World".
This is the only planet known to have liquid water on the surface and the only place in the universe known to harbor life. Earth has a magnetic field that, together with a primarily nitrogen-oxygen atmosphere, protects the surface from radiation that is harmful to life. The atmosphere also serves as a shield that causes smaller meteors to burn up before they strike the surface.
The Earth formed around 4.57 billion years ago and its only known natural satellite, the Moon, began orbiting it around 4.53 billion years ago. At present the Earth orbits the Sun once for every roughly 365.25 times it rotates about its axis. The axial tilt of 23.4° produces seasonal variations on the surface.
Atmospheric conditions on Earth 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. 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, a liquid outer core that generates a magnetic field, and a solid-iron inner core.
The space environment interacts with the Earth to a significant degree. The relatively large moon provides ocean tides, stabilizes the axial tilt and has gradually modified the length of the planet's rotation period. A cometary bombardment during the early history of the planet played a role in the formation of the oceans. Later, asteroid impacts caused significant changes to the surface environment. Long term periodic changes in the orbit of the planet are believed to have caused the ice ages that have covered significant portions of the surface in glacial sheets.
Detailed Google Earth images of British military bases were found in the homes of Iraqi insurgents, a London newspaper reported in January. A British army official told the Daily Telegraph that the confiscated images showed Land Rovers, buildings, tents, and bathroom facilities inside the military compound in Basra, Iraq.
Iron Realms Entertainment today released the 10th chapter for Earth Eternal.
The quote from the article about sums it up. "While the extent of insurgents' use of Google Earth is unknown, the news underscored what some experts see as a growing conflict between national security needs and the software's high-resolution, satellite view of the planet.."
An amazing shot of the solar eclipse from 1.6 million kilometers away from earth. Truly amazing image and a fun little article.
A face staring at me from an Indonesian hillside. I looked closer and realized that this could be the brother of the Martian face as imaged by the Viking Orbiter. Could the Indonesian face be a brother to the Martian face? You all know that I'm just kidding. The Indonesian face is merely shadows on a hillside. Or is it? You decide.