Term:earth

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OVERVIEW OF NOUN EARTH

1) Earth, world, globe: the 3rd planet from the sun; the planet we live on; “the Earth moves around the sun”; “she sailed around the world

Image of earth
Image of earth

2) earth, ground: the loose soft material that makes up a large part of the land surface; “they dug into the earth outside the church

3) land, dry land, earth, ground, solid ground, terra firma: the solid part of the earth’s surface; “the plane turned away from the sea and moved back over land”; “the earth shook for several minutes”; “he dropped the logs on the ground

4) Earth: the abode of mortals (as contrasted with heaven or hell); “it was hell on earth”

5) earth: once thought to be one of four elements composing the universe (Empedocles)

6) worldly concern, earthly concern, world, earth: the concerns of this life as distinguished from heaven and the afterlife; “they consider the church to be independent of the world

7) ground, earth: a connection between an electrical device and a large conducting body, such as the earth (which is taken to be at zero voltage)

OVERVIEW OF VERB EARTH

1) earth: hide in the earth like a hunted animal

2) earth: connect to the earth; “earth the circuit”

noun earth has 7 sense(s) (first 4 from tagged texts)


earth (Wikipedia)
This article is about the planet. For other uses, see Earth (disambiguation).
Earth Astronomical symbol of Earth
"The Blue Marble" photograph of Earth, taken by the Apollo 17 lunar mission. The Arabian peninsula, Africa and Madagascar lie in the upper half of the disc, whereas Antarctica is at the bottom.
"The Blue Marble" photograph of Earth, taken during the Apollo 17 lunar mission in 1972.
Orbital characteristics
Epoch J2000
Aphelion
151930000 km
(1.01559 AU) 
Perihelion
147095000 km
(0.9832687 AU) 
149598261 km
(1.00000261 AU) 
Eccentricity 0.01671123
365.256363004 d
(1.00001742096 yr)
29.78 km/s
(107200 km/h)
358.617 deg
Inclination
−11.26064 deg to J2000 ecliptic
102.94719 deg
Satellites
Physical characteristics
Mean radius
6371.0 km
Equatorial radius
6378.1 km
Polar radius
6356.8 km
Flattening 0.0033528
1/298.257222101 (ETRS89)
Circumference
  • 40075.017 km (equatorial) 
  • 40007.86 km (meridional) 
  • 510072000 km2
  •  (148940000 km2 (29.2%) land
  •   361132000 km2 (70.8%) water)
Volume 1.08321×1012 km3
Mass
5.97219×1024 kg
(3.0×10-6 solar mass)
Mean density
5.514 g/cm3
9.807 m/s2
(g)
0.3307
11.186 km/s
0.99726968 d
(23h 56m 4.100s)
Equatorial rotation velocity
1,674.4 km/h (465.1 m/s)
23 deg 26 min 21.4119 s
Albedo
Surface temp. min mean max
Kelvin 184 K 288 K 330 K
Celsius −89.2 °C 15 °C 56.7 °C
Atmosphere
Surface pressure
101.325 kPa (at MSL)
Composition by volume

Earth, also called the world (and, less frequently, Gaia or, in Latin, Terra), is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to accommodate life. The earliest life on Earth arose at least 3.5 billion years ago. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99 percent of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86 percent have not yet been described. Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade and communication media.

According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Within its first billion years,life appeared in its oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms and causing the formation of the atmosphere's ozone layer.[clarification needed (O3 created from O2 + UV radiation)] This layer blocks the most life-threatening parts of the Sun's radiation, enabling life to flourish on land as well as in water. Since then, the combination of Earth's distance from the Sun, its physical properties and its geological history have allowed life to thrive and evolve.

Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. Seventy-one percent of Earth's surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere. Earth's polar regions are mostly covered with ice, including the Antarctic ice sheet and the sea ice of the polar ice packs. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the magnetic field, and a convecting mantle that drives plate tectonics.

Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.

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