Planet Earth Info
The Planet Earth was formed approximately 4.5 billion years ago. So far, our very own Planet Earth is the only planet that harbors life. From the ancient years, there were many theories regarding the shape of the earth and the many myths associated with it as well. Today, our Planet Earth faces threat due to human intervention and activities. Have you ever wondered how this name was derived? Or what is the approximate distance of the Planet Earth from the sun? Let us now unearth some interesting facts about Planet Earth and know what makes this Planet really so special to usPlanet Earth Facts:- The Earth is not actually round in shape; in fact it is geoid. This simply means that the rounded shape has a slight bulge towards the equator.
- So what causes this geoid shape? This happens solely because the rotation of the Earth which causes the bulge around the equator.
- Earth is the third planet from the Sun. This is also the fifth largest planet in the entire solar system.
- Did you know this interesting fact about Planet Earth that it is the only planet whose name has not been derived from the Roman or Greek mythology? The name has originated from the 8th century Anglo Saxon word- Erda. This means ground or soil.
- Here’s another Planet Earth fact- oceans cover around 70% of the Earth’s surface. The way the water vapor is distributed through the atmosphere results in the weather that is experienced on Planet Earth.
- The Planet Earth takes approximately 23 hours, 56 minutes and 4.091 seconds to rotate around its axis. Therefore, on an average, the Planet Earth takes around 24 hours to complete a full rotation.
- Our Planet Earth is divided into various layers that comprise the surface of the Earth. The Earth’s crust varies in terms of thickness. The inner core and the crust of the Planet Earth are solid in nature. Where as the outer core and the mantle layers are semi fluid in nature. The Earth’s crust is relatively thinner under the ocean floors and thicker in other areas.
- One can note that towards the surface, the air consists of around 78 percent nitrogen with 21 percent oxygen. This air also contains 1 percent of other ingredients. This is the kind of atmosphere that greatly affects the weather of Planet Earth. It also helps to shield us from harmful radiations that may emanate from the Sun.
- Gravity is what keeps all living beings alive and prevents them from falling off the Planet Earth as it completes its rotation.
- Another interesting fact about the Planet Earth is that the gravitational pull between the Earth and the moon is what causes the tides in the oceans and seas. This is also the reason why only one side of the Moon always faces us; the period of rotation is equivalent to the time it takes to orbit the Earth.
BBC - Science & Nature - Planet Earth
This Planet Earth - www.thisplanetearth.co.uk
www.thisplanetearth.co.uk/main/
Earth
From Wikipedia, the free encyclopedia
Famous "Blue Marble" photograph of Earth, taken from Apollo 17 | ||||||||||
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Designations | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Pronunciation | /ˈɜrθ/ ( listen)[1] |
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| Adjective | earthly, tellurian, telluric, terran, terrestrial. | |||||||||
| Epoch J2000.0[note 1] | ||||||||||
| Aphelion | 152,097,701 km 1.0167103335 AU | |||||||||
| Perihelion | 147,098,074 km 0.9832898912 AU | |||||||||
| Semi-major axis | 149,597,887.5 km 1.0000001124 AU | |||||||||
| Eccentricity | 0.016710219 | |||||||||
| Orbital period | 365.256366 days 1.0000175 yr | |||||||||
| Average orbital speed | 29.783 km/s 107,218 km/h | |||||||||
| Inclination | 1.57869°[2] to Invariable plane | |||||||||
| Longitude of ascending node | 348.73936° | |||||||||
| Argument of perihelion | 114.20783° | |||||||||
| Satellites | 1 (the Moon) | |||||||||
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Physical characteristics | ||||||||||
| Mean radius | 6,371.0 km[3] | |||||||||
| Equatorial radius | 6,378.1 km[4] | |||||||||
| Polar radius | 6,356.8 km[5] | |||||||||
| Flattening | 0.0033528[4] | |||||||||
| Circumference | 40,075.02 km (equatorial) 40,007.86 km (meridional) 40,041.47 km (mean) | |||||||||
| Surface area | 510,072,000 km²[6][7][note 2]
148,940,000 km² land (29.2 %) | |||||||||
| Volume | 1.0832073 × 1012 km3 | |||||||||
| Mass | 5.9736 × 1024 kg[8] | |||||||||
| Mean density | 5.515 g/cm3 | |||||||||
| Equatorial surface gravity | 9.780327 m/s²[9] 0.99732 g | |||||||||
| Escape velocity | 11.186 km/s | |||||||||
| Sidereal rotation period |
0.99726968 d[10] 23h 56m 4.100s | |||||||||
| Equatorial rotation velocity | 1,674.4 km/h (465.1 m/s) | |||||||||
| Axial tilt | 23.439281° | |||||||||
| Albedo | 0.367[8] | |||||||||
| Surface temp. Kelvin Celsius |
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Atmosphere | ||||||||||
| Surface pressure | 101.3 kPa (MSL) | |||||||||
| Composition | 78.08% nitrogen (N2) 20.95% oxygen (O2) 0.93% argon 0.038% carbon dioxide About 1% water vapor (varies with climate)[8] | |||||||||
Earth (or the Earth) is the third planet from the Sun, and the fifth-largest of the eight planets in the Solar System. It is also the largest, most massive, and densest of the Solar System's four terrestrial planets. It is sometimes referred to as the World, the Blue Planet,[note 3] or Terra.[note 4]
Home to millions of species,[11] including humans, Earth is the only place in the Universe where life is known to exist. The planet formed 4.54 billion years ago,[12] and life appeared on its surface within a billion years. Since then, Earth's biosphere has significantly altered the atmosphere and other abiotic conditions on the planet, enabling the proliferation of aerobic organisms as well as the formation of the ozone layer which, together with Earth's magnetic field, blocks harmful radiation, permitting life on land.[13] The physical properties of the Earth, as well as its geological history and orbit, allowed life to persist during this period. The world is expected to continue supporting life for another 1.5 billion years, after which the rising luminosity of the Sun will eliminate the biosphere.[14]
Earth's outer surface is divided into several rigid segments, or tectonic plates, that gradually migrate across the surface over periods of many millions of years. About 71% of the surface is covered with salt-water oceans, the remainder consisting of continents and islands; liquid water, necessary for all known life, is not known to exist on any other planet's surface.[note 5][note 6] Earth's interior remains active, with a thick layer of relatively solid mantle, a liquid outer core that generates a magnetic field, and a solid iron inner core.
Earth interacts with other objects in outer space, including the Sun and the Moon. At present, Earth orbits the Sun once for every roughly 366.26 times it rotates about its axis. This length of time is a sidereal year, which is equal to 365.26 solar days.[note 7] The Earth's axis of rotation is tilted 23.4° away from the perpendicular to its orbital plane,[15] producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). Earth's only known natural satellite, the Moon, which began orbiting it about 4.53 billion years ago, provides ocean tides, stabilizes the axial tilt and gradually slows the planet's rotation. Between approximately 4.1 and 3.8 billion years ago, asteroid impacts during the Late Heavy Bombardment caused significant changes to the surface environment.
Both the mineral resources of the planet, as well as the products of the biosphere, contribute resources that are used to support a global human population. The inhabitants are grouped into about 200 independent sovereign states, which interact through diplomacy, travel, trade and military action. Human cultures have developed many views of the planet, including personification as a deity, a belief in a flat Earth or in Earth being the center of the universe, and a modern perspective of the world as an integrated environment that requires stewardship.