Most meteoritic material, by the time it reaches the Earth's surface, has been reduced to dust or to spherules of ablated material in its passage through the atmosphere.

It is the basis for Coordinated Universal Time ( UTC ), which is used for civil timekeeping all over the Earth's surface, and for Terrestrial Time, which is used for astronomical calculations.

With a total area of about, it covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area.

Covering approximately 22 % of Earth's surface, the Atlantic is second in size to the Pacific.

Africa is a continent comprising 62 political territories, representing the largest of the great southward projections from the main mass of Earth's surface.

Due to nuclear scarring of the Earth's surface and atmosphere, the hyperstructure is buried deep underground.

* In Mindstorm's Alpha Omega RPG, the world's populations have retreated into arcology city-states to protect themselves from the war-torn decimation of the Earth's surface

) removes acids from the atmosphere and delivers it to the Earth's surface.

* The case n = 2 is often illustrated by saying that at any moment there is always a pair of antipodal points on the Earth's surface with equal temperatures and equal barometric pressures.

As a result, vegetation forms predicted by conventional biome systems are rarely observed across most of Earth's land surface.

An expanding universe generally has a cosmological horizon which, by analogy with the more familiar horizon caused by the curvature of the Earth's surface, marks the boundary of the part of the universe that an observer can see.

Species which depended on photosynthesis declined or became extinct because of the reduction in solar energy reaching the Earth's surface due to atmospheric particles blocking the sunlight.

These events would have released massive amounts of dust and ash into the atmosphere, reducing surface sunlight, hindering photosynthesis, and severely disrupting Earth's biosphere.

Species that depended on photosynthesis declined or became extinct as atmospheric particles blocked sunlight and reduced the solar energy reaching the Earth's surface.

It is now accepted that the plates carrying the continents do move across the Earth's surface ; ironically one of the chief outstanding questions is the one Wegener failed to resolve: what is the nature of the forces propelling the plates?

He proposed that the Earth's mantle contained convection cells that dissipated radioactive heat and moved the crust at the surface.

* Third, there was the problem of why some parts of the Earth's surface ( crust ) should have solidifed while other parts were still fluid.

Central America has an area of, or almost 0. 1 % of the Earth's surface.

Their awareness of the Earth's surface and abundance of practical skills provided colonisers with a knowledge that, in turn, created power.

The work's subtitle was " An attempt to explain the former changes of the Earth's surface by reference to causes now in operation ", and this explains Lyell's impact on science.

* Observe an animation of the Coriolis effect over Earth's surface

Its surface and shores are below sea level, Earth's lowest elevation on land.

Conversely, there are other stars that never rise above the horizon, as seen from any given point on the Earth's surface ( except exactly on the equator ).

Europe is the world's second-smallest continent by surface area, covering about or 2 % of the Earth's surface and about 6. 8 % of its land area.

Beyond a few million kilometers from the Earth, but still in the region of the Earth's orbit, a prediction of the flux of dust is even more unreliable.

One may conclude that most of the detected micrometeoritic material is concentrated in orbital streams which intersect the Earth's orbit.

International Atomic Time ( TAI, from the French name Temps atomique international ) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid.

The position of the Arctic Circle is not fixed, but directly depends on the Earth's axial tilt, which fluctuates within a margin of 2 ° over a 40, 000 year period, notably due to tidal forces resulting from the orbit of the Moon.

Argon is the third most common gas in the Earth's atmosphere, at 0. 93 % ( 9, 300 ppm ), making it approximately 23. 8 times as abundant as next most common atmospheric gas, carbon dioxide ( 390 ppm ), and more than 500 times as abundant as the next most common noble gas, neon ( 18 ppm ).

Nearly all of this argon is radiogenic argon-40 derived from the decay of potassium-40 in the Earth's crust.

Argon constitutes 0. 934 % by volume and 1. 28 % by mass of the Earth's atmosphere, and air is the primary raw material used by industry to produce purified argon products.

In the Earth's atmosphere, is made by cosmic ray activity, primarily with.

The abundance of antimony in the Earth's crust is estimated at 0. 2 to 0. 5 parts per million, comparable to thallium at 0. 5 parts per million and silver at 0. 07 ppm.

Three years later it was found in nature, although it is the least abundant element in the Earth's crust among the non-transuranic elements, with an estimated total amount of less than at any given time.

It is instrumental for keeping time, in that UTC is basically the atomic time synchronized to Earth's rotation by means of exact observations.

Although, as of 2009, none of the extrasolar planets detected by ground-based astrometry has been verified in subsequent studies, astrometry is expected to be more accurate in space missions that are not affected by the distorting effects of the Earth's atmosphere.

According to Archimedes in the Sandreckoner ( 2. 1 ), Aristarchus of Samos estimated the distance to the Sun to be 10, 000 times the Earth's radius ( the true value is about 23, 000 ).

The Antarctic continent, located in the Earth's southern hemisphere, is centered asymmetrically around the South Pole and largely south of the Antarctic Circle.

Adiabatic cooling occurs in the Earth's atmosphere with orographic lifting and lee waves, and this can form pileus or lenticular clouds if the air is cooled below the dew point.

The most striking feature is the existence of two great lines of depression, due largely to the subsidence of whole segments of the Earth's crust, the lowest parts of which are occupied by vast lakes.

Bolometric magnitude corresponds to luminosity, expressed in magnitude units ; that is, after taking into account all electromagnetic wavelengths, including those unobserved due to instrumental pass-band, the Earth's atmospheric absorption, or extinction by interstellar dust.

Charpak and Broch noted that " there is a difference of about twenty-two thousand miles between Earth's location on any specific date in two successive years " and that thus they should not be under the same influence according to astrology.