Earth, also known as Terra, and Tellus mostly in the 19th century, is the third-closest planet to the Sun. It is the largest of the solar system's terrestrial planets, and the only planetary body that modern science confirms as harboring life. Scientific evidence indicates that the planet formed around 4.57 billion (4.57×109) years ago, and shortly thereafter (4.533 billion years ago) acquired its single natural satellite, the Moon. Earth - Lexicography. Its astronomical symbol con ...

Including:

• Earth - Lexicography
• Earth - Physical characteristics
• Earth - Earth in the solar system
• Earth - The Moon
• Earth - Geography
• Earth - Environment and Ecosystem
• Earth - Climate
• Earth - Terrain
• Earth - Natural resources
• Earth - Land use
• Earth - Natural and environmental hazards
• Earth - Human geography
• Earth - Descriptions of Earth

Read more here: » Earth: Encyclopedia - Earth

See also:

Earth, Earth - Lexicography, Earth - Physical characteristics, Earth - Earth in the solar system, Earth - The Moon, Earth - Geography, Earth - Environment and Ecosystem, Earth - Climate, Earth - Terrain, Earth - Natural resources, Earth - Land use, Earth - Natural and environmental hazards, Earth - Human geography, Earth - Descriptions of Earth

Read more here: » Earth: Encyclopedia II - Earth - Physical characteristics

The Earth consists of several atmospheric, hydrologic, and mainly geologic layers. Its components are the atmosphere, the hydrosphere, the crust, the mantle, and its core. The biosphere is a tiny layer in this composition and is usually not considered part of the physical layers of the Earth. The geologic component layers of the Earth are located at the following depths below surface: 0 to 60 km - Lithosphere (locally varies between 5 and 200 km) 0 to 35 km - Crust (locally varies between 5 and 70 km) 35 ...

See also:

Earth, Earth - Physical characteristics, Earth - Earth in the solar system, Earth - The Moon, Earth - Geography, Earth - Environment and Ecosystem, Earth - Climate, Earth - Terrain, Earth - Natural resources, Earth - Land use, Earth - Natural and environmental hazards, Earth - Human geography, Earth - Descriptions of Earth

Read more here: » Earth: Encyclopedia II - Earth - Physical characteristics

Click image for description Venus, the second planet from the Sun, is named after the Roman goddess Venus. A terrestrial planet, it is sometimes called Earth's "sister planet", as the two are very similar in size and bulk composition. Although all planets' orbits are elliptical, Venus's orbit is the closest to circular, with an eccentricity of less than 1%. As Venus is closer to the Sun than the Earth, it always appears in roughly the same direction from Earth as the Sun (the greatest e ...

Including:

• Venus - Physical characteristics
• Venus - Atmosphere
• Venus - Surface features
• Venus - Venus' moon
• Venus - Aspects
• Venus - Observations and explorations of Venus
• Venus - Lowest distances to earth
• Venus - Cultural references

Read more here: » Venus: Encyclopedia - Venus

Click image for description Neptune is the eighth or, occasionally, the ninth planet from the Sun due to Pluto's eccentric orbit (if Pluto counts as a planet), and the outermost gas giant in our solar system. Although the smallest of the gas giants, Neptune is more massive than Uranus: Its stronger gravitational field has compressed it to a higher density. Faint dark rings have been detected around the blue planet, but are less substantial than those of Saturn. When these ...

Including:

• Neptune - Discovery
• Neptune - Naming
• Neptune - Physical characteristics
• Neptune - Planetary rings
• Neptune - Natural satellites and Trojan asteroids
• Neptune - Appearance and visibility from Earth
• Neptune - Occultation of stars by Neptune between 1800 and 2100
• Neptune - Neptune in fiction and film
• Neptune - Notes

Read more here: » Neptune: Encyclopedia - Neptune

The Cybermen are a fictional race of cyborgs who are amongst the most persistent enemies of the Doctor in the British science fiction television series, Doctor Who. They were created by Dr. Kit Pedler, the unofficial scientific advisor to the programme and Gerry Davis in 1966, first appearing in the serial, The Tenth Planet, the last to feature William Hartnell as the First Doctor. They have since made numerous reappearances in their bid for world or galactic conquest. The Cybermen are due to reappear in the 2006 series ...

Including:

• Cyberman - Physical characteristics
• Cyberman - Technology
• Cyberman - Weapons
• Cyberman - Cybermats
• Cyberman - Costume design
• Cyberman - History within the show
• Cyberman - Origins
• Cyberman - The Earth invasions
• Cyberman - The Cyber-Wars
• Cyberman - Other appearances
• Cyberman - Spin-offs
• Cyberman - Popular culture
• Cyberman - Major appearances
• Cyberman - Television
• Cyberman - Stage plays
• Cyberman - Audio plays
• Cyberman - Novels

Read more here: » Cyberman: Encyclopedia - Cyberman

The Moon as seen from Earth Ammonia Carbon dioxide The Moon is the planet Earth's only natural satellite. It has no formal name other than "The Moon", although in English it is occasionally called Luna (Latin for moon), or Selene, to distinguish it from the generic "moon" (natural satellites of other planets are also called moons). Its symbol is a crescent (Unicode: ☾). The terms lunar, selene/seleno-, and cynthion (from the Lunar deities Selene and Cynthia) refer to the Moon (apo ...

Including:

• Moon - The two sides
• Moon - Orbit
• Moon - Earth & Moon
• Moon - Origin and history
• Moon - Physical characteristics
• Moon - Composition
• Moon - Selenography
• Moon - Presence of water
• Moon - Magnetic field
• Moon - Atmosphere
• Moon - Eclipses
• Moon - Occultation of stars
• Moon - Observation of the Moon
• Moon - Exploration of the Moon
• Moon - Human understanding of the Moon
• Moon - Myth and folk culture
• Moon - The Moon as muse
• Moon - Astrology
• Moon - Scientific understanding
• Moon - Meteor impact on the Moon
• Moon - Legal status
• Moon - Satellites
• Moon - Surface installations
• Moon - Lunar location listings

Read more here: » Moon: Encyclopedia - Moon

A magnet is an object that has a magnetic field. The word magnet comes from the Greek "magnítis líthos" (μαγνήτης λίθος), which means "magnesian stone". Magnesia is an area in Greece (Now Manisa, Turkey) where deposits of magnetite have been discovered since antiquity. Magnet - Introduction. In the modern sense, a magnet is any material that has a magnetic field. It can be in the form of a permanent magnet or an electromagnet. Permanent magnets do not rely upon outside in ...

Including:

• Magnet - Introduction
• Magnet - Physical origin of magnetism
• Magnet - Permanent Magnets
• Magnet - Electromagnets
• Magnet - Characteristics of magnetic materials
• Magnet - Permanent magnets and dipoles
• Magnet - North/south pole designation and the Earth's magnetic field
• Magnet - Common uses for magnets
• Magnet - How to magnetize materials
• Magnet - How to demagnetize materials
• Magnet - Types of permanent magnets
• Magnet - Magnetic forces
• Magnet - Magnets and other magnets
• Magnet - Magnets and ferromagnetic materials
• Magnet - Magnets and diamagnetic materials
• Magnet - Magnets and paramagnetic materials
• Magnet - Calculating the magnetic force
• Magnet - Online references
• Magnet - Printed references
• Magnet - External articles

Read more here: » Magnet: Encyclopedia - Magnet

A world map is a map of the surface of the Earth, which may be made using any of a number of different map projections. Maps of the world are often either 'political' or 'physical'. The most important purpose of the political map is to show territorial borders; the purpose of the physical map is to show features of geography such as mountains, soil type or land use. Geological maps show not only the physical surface, but characteristics of the underlying rock, fault lines, and subsurface structures. World map - Pr ...

Including:

• World map - Projections
• World map - Projections

Read more here: » World map: Encyclopedia - World map

The asteroid 433 Eros (eer'-os) was named after the Greek god of love Eros. It is an S-type asteroid approximately 13 × 13 × 33 km in size, the second-largest near-Earth asteroid. It is also a Mars-crosser asteroid. Eros was visited by the NEAR Shoemaker probe, which orbited it, taking extensive photographs of its surface, and then, on February 12, 2001 at the end of its mission, landed on the asteroid's surface using only its maneuvering jets. 433 Eros - Physical characteristics. Surface gr ...

Including:

• 433 Eros - Physical characteristics
• 433 Eros - Legal controversy
• 433 Eros - Aspects
• 433 Eros - Eros in fiction

Read more here: » 433 Eros: Encyclopedia - 433 Eros

6 Hebe (hee'-bee, Greek ‘Ήβη) is one of the largest Main belt asteroids, and is probably the parent body of the H chondrite meteorites, which account for a remarkable 40% of all meteorites striking the Earth. 6 Hebe - Discovery. Hebe was the sixth asteroid to be discovered, on July 1, 1847. It was the second and final asteroid discovery by Karl Ludwig Hencke, who had previously found 5 Astraea. The name "Hebe" was proposed by Carl Friedrich Gauss, and refers to the Greek goddess of youth, ...

Including:

• 6 Hebe - Discovery
• 6 Hebe - Major meteorite source
• 6 Hebe - Physical characteristics
• 6 Hebe - Jebe
• 6 Hebe - Aspects

Read more here: » 6 Hebe: Encyclopedia - 6 Hebe

4 Vesta (ves'-tə, IPA /ˈvɛstə/) is the second most massive asteroid in the asteroid belt, with a mean diameter of about 530 km and an estimated mass 12% the mass of the entire asteroid belt. Its size and unusually bright surface make Vesta the brightest asteroid, and the only one ever visible to the naked eye from Earth, apart from 1 Ceres under exceptional viewing conditions. Due to the availability of rock samples in the form of the HED meteorites, it has also been the ...

Including:

• 4 Vesta - Discovery
• 4 Vesta - Physical characteristics
• 4 Vesta - Geology
• 4 Vesta - Surface features
• 4 Vesta - Further details
• 4 Vesta - Aspects

Read more here: » 4 Vesta: Encyclopedia - 4 Vesta

Mars is the fourth planet from the Sun in our solar system. It is named after Mars, the Roman god of war (Ares in Greek mythology). Its name was chosen because of its red color, a feature that also earned it the nickname "The Red Planet". Mars has two moons, Phobos and Deimos, both are small and oddly-shaped, each possibly being captured asteroids. The prefix areo- refers to Mars in the same way geo- refers to Earth—for example, areology versus geology. (Areology is also used to refer to the study of Mars as a whole rather than ju ...

Including:

• Mars - Mythology
• Mars - Physical characteristics
• Mars - Atmosphere
• Mars - Geology
• Mars - Topography
• Mars - Canals
• Mars - Ice patches
• Mars - The moons of Mars
• Mars - The exploration of Mars
• Mars - Nomenclature
• Mars - Early nomenclature
• Mars - Modern nomenclature
• Mars - Observation of Mars
• Mars - Appearance
• Mars - Martian meteorites
• Mars - Life on Mars
• Mars - The Mars flag
• Mars - Mars in fiction

Read more here: » Mars: Encyclopedia - Mars

A UFO or Unidentified Flying Object is simply defined as any object or optical phenomenon observed in the sky which cannot be identified, even after being thoroughly investigated by qualified people. A fuller definition was given by Dr. J. Allen Hynek, late astronomer, U.S. Air Force consultant and UFO proponent, as "the reported perception of an object or light seen in the sky or upon the land the appearance, trajectory, and general dynamic and luminescent behaviour of which do not suggest a logical, conve ...

Including:

• Unidentified flying object - History
• Unidentified flying object - Etymology
• Unidentified flying object - Foreign versions of term
• Unidentified flying object - Pronunciation
• Unidentified flying object - UFOs and popular culture
• Unidentified flying object - Typical reported characteristics of UFOs
• Unidentified flying object - Scientific UFO field studies
• Unidentified flying object - Norway
• Unidentified flying object - United States
• Unidentified flying object - Official governmental studies
• Unidentified flying object - Canada
• Unidentified flying object - United States
• Unidentified flying object - Civilian UFO investigation groups
• Unidentified flying object - United States
• Unidentified flying object - Other UFO organizations
• Unidentified flying object - Science and UFOs
• Unidentified flying object - Physical evidence
• Unidentified flying object - Identified flying objects IFOs
• Unidentified flying object - Popular ideas for explaining UFOs
• Unidentified flying object - Evidence and explanations
• Unidentified flying object - Evidence and suppression
• Unidentified flying object - Hoaxes or reality
• Unidentified flying object - Psychology
• Unidentified flying object - Paranormal mystical and occult crossover
• Unidentified flying object - Politics
• Unidentified flying object - Conspiracy theories
• Unidentified flying object - Notable UFO-related sightings and events
• Unidentified flying object - Prominent UFO researchers
• Unidentified flying object - Theories
• Unidentified flying object - Film and television
• Unidentified flying object - Sources

Read more here: » Unidentified flying object: Encyclopedia - Unidentified flying object

Venus - Atmosphere. Venus has an atmosphere consisting mainly of carbon dioxide and a small amount of nitrogen, with a pressure at the surface about 90 times that of Earth (a pressure equivalent to a depth of 1 kilometer under Earth's oceans); its atmosphere is also roughly 90 times more massive than ours. This enormously CO2-rich atmosphere results in a strong greenhouse effect that raises the surface temperature more than 400 °C (750 °F) above what it would be otherwise, causing temperatu ...

See also:

Venus, Venus - Physical characteristics, Venus - Atmosphere, Venus - Surface features, Venus - Venus' moon, Venus - Aspects, Venus - Observations and explorations of Venus, Venus - Lowest distances to earth, Venus - Cultural references

Read more here: » Venus: Encyclopedia II - Venus - Physical characteristics

Orbiting so far from the sun, Neptune receives very little heat — in fact the uppermost regions of the atmosphere are −218 °C (55 K). Because Neptune is a gas giant, there is no solid surface; as one ventures deeper and deeper inside the layers of gas, however, the temperature rises steadily. It is thought that this may be leftover heat generated by infalling matter during the planet's birth, now slowly radiating away into space. Neptune's atmosphere has the highest wind speeds in the solar system, up to 2000 km/h, ...

See also:

Neptune, Neptune - Discovery, Neptune - Naming, Neptune - Physical characteristics, Neptune - Planetary rings, Neptune - Natural satellites and Trojan asteroids, Neptune - Appearance and visibility from Earth, Neptune - Occultation of stars by Neptune between 1800 and 2100, Neptune - Neptune in fiction and film, Neptune - Notes

Read more here: » Neptune: Encyclopedia II - Neptune - Physical characteristics

The Cybermen are humanoid, but have been cybernetically augmented to the point where they have few to no organic parts. In their first appearance in the series, the only portions of their bodies that still seemed human were their hands, but by their next appearance, their bodies were entirely covered up in their metallic suits. It is presumed (and often implied) that beneath their suits still exist organic components and that they are not true robots: in The Tenth Planet, a Cyberman tells a group of humans that "our brains are ...

See also:

Cyberman, Cyberman - Physical characteristics, Cyberman - Technology, Cyberman - Weapons, Cyberman - Cybermats, Cyberman - Costume design, Cyberman - History within the show, Cyberman - Origins, Cyberman - The Earth invasions, Cyberman - The Cyber-Wars, Cyberman - Other appearances, Cyberman - Spin-offs, Cyberman - Popular culture, Cyberman - Major appearances, Cyberman - Television, Cyberman - Stage plays, Cyberman - Audio plays, Cyberman - Novels

Read more here: » Cyberman: Encyclopedia II - Cyberman - Physical characteristics

The Cybermen are humanoid, but have been cybernetically augmented to the point where they have few to no organic parts. In their first appearance in the series, the only portions of their bodies that still seemed human were their hands, but by their next appearance, their bodies were entirely covered up in their metallic suits. It is presumed (and often implied) that beneath their suits still exist organic components and that they are not true robots: in The Tenth Planet, a Cyberman tells a group of humans that "our brains are ...

See also:

Cyberman, Cyberman - Physical characteristics, Cyberman - Costume design, Cyberman - Technology, Cyberman - Weapons, Cyberman - Cybermats, Cyberman - History within the show, Cyberman - Origins, Cyberman - The Earth invasions, Cyberman - The Cyber-Wars, Cyberman - Other appearances, Cyberman - Spin-offs, Cyberman - Popular culture, Cyberman - Major appearances, Cyberman - Television, Cyberman - Stage plays, Cyberman - Audio plays, Cyberman - Novels

Read more here: » Cyberman: Encyclopedia II - Cyberman - Physical characteristics

Titan is larger than the planet Mercury[6] (though less massive) and is the second largest natural satellite in the solar system after Ganymede[7]. It was originally thought to be slightly larger than Ganymede, this error was caused because there is a haze in its atmosphere which extends nearly 300 km above the surface and is almost opaqu ...

See also:

Titan moon, Titan moon - Name, Titan moon - Visibility from Earth, Titan moon - Physical characteristics, Titan moon - Atmosphere, Titan moon - Surface features, Titan moon - Exploration of Titan, Titan moon - Titan in fiction, Titan moon - Titan in literature, Titan moon - Titan in cinema and television, Titan moon - Titan in comics and anime, Titan moon - Titan in video games, Titan moon - Notes

Read more here: » Titan moon: Encyclopedia II - Titan moon - Physical characteristics

Moon - Composition. More than 4.5 billion years ago, the surface of the Moon was a liquid magma ocean. Scientists think that one component of lunar rocks, KREEP (K-potassium, Rare Earth Elements, and P-phosphorus), represents the last chemical remnant of that magma ocean. KREEP is actually a composite of what scientists term "incompatible elements": those which cannot fit into a crystal structure and thus were left behind, floating to the surface of the magma. For researchers, KREEP is a convenient tracer, useful ...

See also:

Moon, Moon - The two sides, Moon - Orbit, Moon - Earth & Moon, Moon - Origin and history, Moon - Physical characteristics, Moon - Composition, Moon - Selenography, Moon - Presence of water, Moon - Magnetic field, Moon - Atmosphere, Moon - Eclipses, Moon - Occultation of stars, Moon - Observation of the Moon, Moon - Exploration of the Moon, Moon - Human understanding of the Moon, Moon - Myth and folk culture, Moon - The Moon as muse, Moon - Astrology, Moon - Scientific understanding, Moon - Meteor impact on the Moon, Moon - Legal status, Moon - Satellites, Moon - Surface installations, Moon - Lunar location listings

Read more here: » Moon: Encyclopedia II - Moon - Physical characteristics