At the Maragha observatory, Najm al-Dīn al-Qazwīnī al-Kātibī ( d. 1277 ), in his Hikmat al -' Ain, wrote an argument for a heliocentric model, but later abandoned the model.

At this time, cities such as Bukhoro ( Bukhara ) and Samarqand ( Samarkand ) began to appear as centers of government and culture.

At times Samarkand has been one of the greatest cities of Central Asia.

At the start of the 8th century Samarkand came under Arab control.

At the same time, most personnel and production units of the Lenfilm studio were evacuated to cities in Central Asia, such as Alma-Ata ( 1942 ) and Samarkand.

At Samarkand, they discover a not-quite-sane submind of the destroyed Runcible AI.

At first submissive to Abu Sa ' id, he took advantage of the Samarkand ruler's attempts to put down a revolt in Transoxiana in 1460 ; by the following year he was laying siege to Herat, which had fallen into Abu Sa ' id's hands in 1459.

At the entrance to the Samarqand Province from the Qashqadaryo Province Samarkand is the 2nd largest center for economy, science, and culture in Uzbekistan, after Tashkent.

" At any particular time of history there have always been one or two cities of the monstrous sort -- viz., Babel or Babylon, Ur-Lhassa, Nineve, Syracuse, Rome, Samarkand, Tenochtitlan, Peking -- but we live in the Megapolitan ( or Necropolitan ) Age, when such disastrous blights are manifold and threaten to conjoin and enshroud the world with funebral yet multipotent city-stuff.

At the time, UT2 as published by various observatories differed by several centiseconds.

At most observatories the turbulence is only significant on scales larger than r < sub > 0 </ sub > ( see below — the seeing parameter r < sub > 0 </ sub > is 10 – 20 cm at visible wavelengths under the best conditions ) and this limits the resolution of telescopes to be about the same as given by a space-based 10 – 20 cm telescope.

At the best high-altitude mountaintop observatories the wind brings in stable air which has not previously been in contact with the ground, sometimes providing seeing as good as 0. 4 ".

At the time of the Peloponnesian War, stone observatories were built at the sites of Prophet Elias and Zogeria.

At one astronomical unit from the sun ( the Earth's distance ) the dust orbits are probably nearly circular.

At the peak of the Cretaceous transgression, one-third of Earth's present land area was submerged.

At the Survey, he worked mainly in geodesy and gravimetry, refining the use of pendulums to determine small local variations in the Earth's gravity.

At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground.

At the close of the 20th Century, all of the Earth's kaiju have been collected and confined in an area known as Monster Island, by the United Nations Science Committee, in the Ogasawara island chain.

At its height, the British Empire covered a quarter of the Earth's land area and comprised a quarter of its population.

The idea was used by Edgar Rice Burroughs, the creator of Tarzan, in the seven-novel " Pellucidar " series, beginning with At the Earth's Core ( 1914 ).

At that time it had lost the first page, but the second ( the current beginning of the Ynglinga Saga ) starts Kringla heimsins, " the Earth's circle " of the Laing translation.

At Standard Sea Level conditions ( corresponding to a temperature of 15 degrees Celsius ), the speed of sound is 340. 3 m / s ( 1225 km / h, or 761. 2 mph, or 661. 5 knots, or 1116 ft / s ) in the Earth's atmosphere.

At Earth's orbit its typical density is 6 ions / cm < SUP > 3 </ SUP > ( variable, as is the velocity ), and it contains a variable interplanetary magnetic field ( IMF ) of ( typically ) 2 – 5 nT.

At 10-15 kilometers ( 6 – 9 miles ) above the Earth's surface, the absorption of sunlight would further heat the smoke, lifting some, or all of it, into the stratosphere, to where the smoke would persist for years, with no rain to wash it out.

At 165. 25 million square kilometres ( 63. 8 million square miles ) in area, this largest division of the World Ocean – and, in turn, the hydrosphere – covers about 46 % of the Earth's water surface and about one-third of its total surface area, making it larger than all of the Earth's land area combined.

At first, oxygen would quickly combine with other elements in Earth's crust, primarily iron, as it was produced.

# At the Earth's Core ( 1914 )

The first novel was filmed as At the Earth's Core ( 1976 ), directed by Kevin Connor and starring Doug McClure as David Innes and Peter Cushing as Abner Perry.

* At the Earth's Core ( 1976 movie )

Image: AtTheEarthsCore. jpg | At the Earth's Core-1960s paperback

At, Russia is the largest country in the world, covering more than one-eighth of the Earth's inhabited land area.

At standard temperature and pressure, radon forms a monatomic gas with a density of 9. 73 kg / m < sup > 3 </ sup >, about 8 times the density of the Earth's atmosphere at sea level, 1. 217 kg / m < sup > 3 </ sup >.

At the measured distance of Vega, this corresponded to an actual radius of 80 astronomical units ( AU ), where an AU is the average radius of the Earth's orbit around the Sun.

At high latitudes ( near the Earth's poles ), they are very low, making communication difficult or impossible due to factors such as atmospheric refraction, Earth's thermal emission, line-of-sight obstructions, and signal reflections from the ground or nearby structures.

At that point in Earth's history these rocks made up the soft bottom sediments of a large, shallow ocean, which stretched across much of North America.

At the Earth's surface, earthquakes manifest themselves by vibration, shaking and sometimes displacement of the ground.

At some small angular rate of rotation, however, an element of surface water can achieve lower potential energy by moving outward under the influence of the centrifugal force.

At these very high vacuums the effect of photon radiation pressure on the vanes can be observed in very sensitive apparatus ( see Nichols radiometer ) but this is insufficient to cause rotation.

At the completion of the required number of twist rotations, the arm motion is reversed ( the steering wheel is turned back ), which removes the body's tilt and stops the twisting rotation.

At the start of the season the Padres starting rotation order was as follows: Jake Peavy, Chris Young, Clay Hensley ( injured, replaced by Justin Germano ), Greg Maddux, David Wells.

At the same time, vika is the same word as a week ' seven days '; in both cases the real meaning is ' a shift, a rotation '.

At the high end of estimates for the rotation velocity for Vega is along the equator ( for a rotation period of about 12. 5 hours ), which is 87. 6 % of the speed that would cause the star to start breaking up from centrifugal effects.

At certain rotation angles, the reflected light will be reduced or eliminated.

At moderate frequencies, the energy is too high to cause rotation, yet too low to affect electrons directly, and is absorbed in the form of resonant molecular vibrations.

At either the North Pole or South Pole, the plane of oscillation of a pendulum remains fixed relative to the distant masses of the universe while Earth rotates underneath it, taking one sidereal day to complete a rotation.

At a distance of 60, 000 to 70, 000 km from the Moon, the orientation system was turned on and the spacecraft rotation was stopped.

At the quantum mechanical level, the information content of circular dichroism and optical rotation are identical.

At the same time, one archbishop and three bishops from Ireland ( selected by rotation ) were given seats in the House of Lords at Westminster, joining the two archbishops and twenty-four bishops from the Church of England.

At this latitude, the Earth's rotation gives a velocity of approximately when the launch trajectory heads eastward.

At the end of the 19th century, meteorologists recognized that the way the Earth's rotation is taken into account in meteorology is analogous to what Coriolis discussed: an example of Coriolis Effect.

These terms are also used colloquially by scientists and engineers to describe phenomena that can be neglected as not significant ( e. g., " Of course the rotation of the earth affects our experiment, but it's such a high-order effect that we wouldn't be able to measure it " or " At these velocities, relativity is a fourth-order effect that we only worry about at the annual calibration.

* At the beginning of this year an extreme decadal variation in length of day produces mean solar days having a duration of 86400. 00389 seconds of Terrestrial Time ( or ephemeris time ), the slowest rotation of Earth's crust ever to be recorded.

At high speeds, when a car tends to turn, its outer and inner wheels are subjected to different speed of rotation, that is conventionally controlled by using a differential.

At Utrecht the program consists of two and a half year of theory, two and a half year specialty-dedicated theory blocks, a clinical rotation in that specialty, and one year continuous practical experience.

At any one time, an Archbishop and three Bishops represented Ireland, with the seats passing according to a fixed rotation, except that those Lords Spiritual who were also elected to serve as representative peers would be omitted.

At least five processes can be involved in altering tide levels during storms: the pressure effect, the direct wind effect, the effect of the Earth's rotation, the effect of waves, and the rainfall effect.

At the International Astronomical Union ( IAU ) meeting in Dublin in 1955, he had proposed the system of distinguishing between variants of Universal Time, as UT0 ( UT as directly observed ), UT1 ( reduced to invariable meridian by correcting to remove effect of polar motion ) and UT2 ( further corrected to remove ( extrapolated ) seasonal variation in earth rotation rate ), a system which remains in some use today.

At the launch, then -" Hot 97. 5 " was the first urban station in Atlanta to feature hip hop and rap music in regular rotation, given the fact that hip hop and rap music on radio was still a niche genre at the time for Atlanta in spite of its major African American presence in the audience and the music culture.

At the peaks of the torsion function the rotation of the Frenet-Serret frame ( T, N, B ) around the tangent vector is clearly visible.