|Venus > Earth > Luna (The Moon)|
"How inappropriate to call this planet Earth when it is quite clearly Ocean." --Arthur C. Clarke
Discovery date: Always known.
Discoverer(s): The ancients.
Detection method: Unaided eye.
|Formula:||Oxygen, xenon, argon, carbon, carbon dioxide, water vapour|
|Age:||4.4 billion years|
|Temperature:||-129°F to 136°F|
|Rotation:||23 hrs 56 mins 4 secs|
|Orbital motion:||1.0 miles/second|
|Type:||Terrestrial planet, rocky planet|
|Voice actor(s):||Alexis Herrera|
|Death:||Killed by black hole (revived), vaporized (revived again), engulfed by the Sun (revived again), tore by black holes (revived again)|
|Life forms:||Humans, animals, plants|
|Mass:||318 times Ceres|
It is the largest of the local planetary system's terrestrial planets and is uniquely situated in a zone around the Sun to allow life to flourish. The Earth is believed to have formed around 4.4 billion years ago (see Age of the Earth) and its largest natural satellite, the Moon, is thought to have been orbiting it shortly thereafter, around 4.4 billion years ago. Since it formed, the earth has apparently changed through geological and biological processes that have hidden any trace of the original conditions.
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 Earth mantle and an iron core that generates a magnetic field. The atmospheric conditions have been significantly altered by the presence of life forms, which create an ecological balance that modifies the surface conditions.
Earth (IPA: /ɝθ/) is the hospitable, blue, third planet from the Sun and is the largest of the terrestrial planets in The Solar System, by both diameter and mass. Home to the millions of diverse life forms including the intelligent human race, it is also referred to as "The Earth", "Planet Earth", "Gaia" (after the greek goddess Gaia), and "The World". Earth is the only planet known to have liquid water on the surface and is the only place in the universe certain to harbor life. Earth has an intence magnetic field that, together with a thick ozone layer, protects the surface from dangerous solar radiation that is harmful to most of Earth's ecosystem. Its atmosphere is mostly comprised of nitrogen, oxygen, and water vapor. The atmosphere also serves as a shield that causes most small meteors to burn up before they can strike the surface though sometimes meteors do strike the surface. Earth formed around 4.4 billion years ago and its only known natural satellite, The Moon, began orbiting after a large planetary collision occured around 4.4 billion years ago. For over 1 billion years atmospheric conditions on Earth have been greatly altered by the formation of life forms, which created an ecological balance that inadvertently changed the atmosphere. About 71% of the surface is covered with salt-water oceans filled with sodium, chloride, magnesium, and several other salts. These oceans provide a sanctuary for many life forms that thrive there. The remaining 29% consists of continents and islands which are also inhabited by many life forms. The planet's outer surface is divided into several solid moving sections, or tectonic plates, that gradually migrate across the surface over periods of many millions of years, they also help to recycle the land forming new land and sloshing old land back to the mantle over a period of millions of years. Earth's interior remains very active, with a thick layer of relatively solid mantle, a liquid outer core that generates a protective magnetic field, and a thick solid-iron inner core.
Earth at glance Edit
- Distance from the Sun: 96,000,000 miles
- Diameter: 7,909 miles
- Length of year: 365.25 days
- Temperature: -126°F & 57°F to 136°F.
- Mass: 330 times Ceres
- Atmosphere: Oxygen (O2), carbon dioxide (CO2), argon, and water vapour (climate variable).
- Number satellites: 2
- Rotation period: 23 hours, 56 minutes, and 4 seconds.
About 70% 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 formed the oceans. Later, asteroid impacts are understood to have caused significant changes to the surface environment. 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.
The Earth's only natural orbiting body is the moon, although the asteroid Cruithne has been erroneously described as such. Cruithne was discovered in 1986 and follows an elliptical orbit around the Sun at about the same average orbital radius as the Earth. However, from the point of view of the moving Earth, Cruithne follows a horseshoe orbit around the Sun that avoids close proximity with the Earth.
- NASA's Earth fact sheet
- Discovering the Essential Universe (Second Edition) by Neil F. Comins (2001)
- space.about.com - Earth - Pictures and Astronomy Facts
- ↑ G.B. Dalrymple, 1991, "The Age of the Earth", Stanford University Press, California, ISBN 0-8047-1569-6.
- WikiSatellite view of Earth at WikiMapia
- USGS Geomagnetism Program
- Overview of the Seismic Structure of Earth Template:PDFlink
- NASA Earth Observatory
- Beautiful Views of Planet Earth Pictures of Earth from space
- Java 3D Earth's Globe
- Projectshum.org's Earth fact file (for younger folk
- MySolarSystem.com - Earth Facts about Earth and the moon.
- Alexis Herrera (UK/US; fifteenth season onwards)
- Yuka Shioyama (Japan; tenth season onwards)
- Blanche Ravalec (Mexico; tenth season onwards)
- Earth is the only planet that we know of that definitely supports life.
- It is predicted to support life for another 500 million years.
- Position from the Sun: Third.
- Fifth largest planet of the eight planets, and largest terrestrial planet in the Solar System.
- Has the largest moon of all inner planets.
- It is located in a band of space called the Goldilocks zone where the conditions are perfect for "Earth-like" life.