Orbit of the Earth

The sun is an almost spherical radiation source with a diameter of 1.392 106 km. It lies in one of the foci of the elliptical orbit of the earth. The solar radiation flow, which reaches the earth is inversely proportional to the square of the distance r between the sun and the earth. The mean distance is r0 = 149.6 106 km this distance is called one astronomical unit (AU)7. The smallest distance lies at 0.983 AU and occurs on 3rd January, the largest separation between the sun and... 

The rotational axis of the Earth gradually precesses like that of a spinning top, and the ellipitical orbit of the Earth also precesses. The periods of these two precessions are 19 and 23 kyr, respectively, yielding an average of c.21 kyr. Precession controls the distribution of insolation over the Earth s surface by varying the timing of the seasons relative to the perihelion, but, like obliquity, does not affect the total insolation. 

For periodic events, iperwd the time that it takes for the event to repeat itself. For example, every 365.24 days the earth lines up in exacdy the same position with respect to the sun. The orbit of the earth around the sun is said to be periodic because this event repeats itself. The inverse of a period is called frequency. For example, the frequency at which the earth goes around the sun is once a year. 

Actually, they provide the standard stratigraphic framework into which Pleistocene climatic events can be placed. In this respect, radiometric dating has been invaluable in establishing an absolute stratigraphy for the past 800,000 years. A model was developed in which the isotope is envisaged as a response of a single exponential system induced by variations in obliquity and precession of the orbit of the Earth (Imbrie et al. 1984). 

Near-Earth Object (NEO) Asteroid or comet whose orbit comes near or crosses the orbit of the Earth. 

PI films loaded with 15 wt. % of Si-microcapsules loaded with TMPTA monomer exposed 30 min are equivalent to 6 month exposure at the real space condition over geostationary orbit of the earth. 

Yuri Alexeyevich Gagarin s (1961) and lohn Glenn s (1962) pioneering orbits of the Earth extended the reach of human life to space. 

The sun radiates approximately as a blackbody, with an effective temperature of about 6000 K. The total solar flux is 3.9 x 10 W. Using Wien s law, it has been found that the frequency of maximum solar radiation intensity is 6.3 x 10 s (X = 0.48 /rm), which is in the visible part of the spectrum 99% of solar radiation occurs between the frequencies of 7.5 X 10 s (X = 4/um) and 2 x 10 s (X = 0.15/um) and about 50% in the visible region between 4.3 x 10 s (X = 0.7 /rm) and 7.5 X 10 s (X = 0.4 /Ltm). The intensity of this energy flux at the distance of the earth is about 1400 W m on an area normal to a beam of solar radiation. This value is called the solar constant. Due to the eccentricity of the earth s orbit as it revolves around the sun once a year, the earth is closer to the sun in January (perihelion) than in July (aphelion). This results in about a 7% difference in radiant flux at the outer limits of the atmosphere between these two times. 

The high sensitivity of atomic Sagnac interferometers to rotation rates will enable HYPER to measure the modulation of the precession due to the Lense-Thirring effect while the satellite orbits around the Earth. In a Sun-synchronous, circular orbit at 700 km altitude, HYPER will detect how the direction of the Earth s drag varies over the course of the near-polar orbit as a function of the latitudinal position 9 ... 

A collision with a Mars-sized object may have resulted in the formation of the Earth s moon. Our moon is by no means the largest satellite in the solar system, but it is unusual in that it and the moon of Pluto are the largest moons relative the mass of the planets they orbit. Geochemical studies of returned lunar samples have shown that close similarities exist between the bulk composition of the moon and the Earth s mantle. In particular, the abimdances of sidero-... 

It turns out that the GPS allows one to obtain information about the gravitational field of the earth and we will briefly outline here two different approaches. The first approach is based on the study of the satellite orbit while the other requires measurements of the satellite height. 

After the review of literature, we report here the results of the degradation of phenol, carried out in our laboratory in the presence of ultrasound, Ti02, rare earths and transition metal ions to highlight our interpretation of the mechanism. Various transition metal salts are known for their catalytic properties due to partly filled d-orbital of the metal atom. Mesoporous transition metal oxides are used not... 

In the region of the terrestrial planets, there may have been several thousand planetesimals of up to several hundred kilometres in diameter. During about ten million years, these united to form the four planets—Mercury, Venus, Earth and Mars—which are close to the sun. Far outside the orbit of the planet Mars, the heavier planets were formed, in particular Jupiter and Saturn, the huge masses of which attracted all the hydrogen and helium around them. Apart from their cores, these planets have a similar composition to that of the sun. Between the planets Mars and Jupiter, there is a large zone which should really contain another planet. It... 

The transit method requires that the central star, the planet and the observer are connected by a line of sight. The dark planet passes across the light source and thus diminishes its light intensity to some extent. Observation is only possible when observer, star and planet are in a favourable position, i.e., the planet lies between the star and the observer. In spite of this requirement, the method permits the discovery of planets of about the size of the Earth information is also available on the size, mass and density of the planet as well as on its orbit. Because of its limits of applicability, this method is not often used. In the case of the star OGLE-TR-56, it was possible to detect an extrasolar planet, the orbit of which is very close to its sun only a twentieth of the distance of Mercury away from it. The temperature of the planet was determined to be around 1,900 K its diameter is about 1.3 times larger than that of Jupiter, its density about 500 kg/m3 (Brown, 2003 Konacki, 2003). 

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