OBBIT: The Earth orbits the Sun at an average distance of 150 million miles, completing a solar orbit every 365.2564 days, or one sidereal year. From Earth, this creates an apparent movement of the Sun eastward moving with respect to the stars at a rate of about 1 ° / day, or a diameter of the Sun or Moon every 12 hours. Because of this motion, on average it takes the Earth 24 hours (one solar day) to complete one rotation on its axis until the sun returns to the meridian. The orbital speed of the Earth is about 29.8 km / s (107,000 km / h), which is fast enough to traverse the diameter of Earth (12,742 km) in seven minutes, or the distance between the Earth and Moon (384,000 km) in four hours.
ROTATION: The rotation period of the Earth from the Sun, ie, a solar day is around 86 400 second solar time (86 400.0025 seconds SIU) .130 The Earth solar day is now slightly longer than it was during the nineteenth century due to tidal acceleration, the days last between 0 and 2 ms SIU's.
martes, 7 de octubre de 2014
COMPOSITION AND STRUCTURE
FORM: The shape of the Earth is very similar to that of an oblate spheroid, a sphere flattened at the poles, resulting in a bulge around the ecuador.Este bulge is caused by the rotation of the Earth, and causes the diameter at the Ecuador is 43 km longer than the diameter of one pole to another. Approximately 22 000 years ago the Earth had a more spherical shape, most of the northern hemisphere was covered by ice, and as the ice melted causing less pressure on the earth's surface that is causing this type held "rebound", this phenomenon continued to occur until the mid-nineties when scientists realized that this process was reversed, ie, the swelling increased, satellite observations GRACE show that at least since 2002, the ice loss from Greenland and Antarctica has been primarily responsible for this trend. The average diameter of the reference spheroid is about 12,742 km, which is approximately 40,000 km / π, as the meter was originally defined as one ten-millionth of the distance from Ecuador to the North Pole from Paris, France.
CHEMICAL COMPOSITION: The mass of the Earth is approximately 5.98 × 1024 kg. (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8% It is composed mainly of iron ), calcium (1.5%) and aluminum (1.4%), with the remaining 1.2% consisting of small amounts of other elements. Because mass segregation, it is believed that the core region is mainly composed of iron (88.8%), with small amounts of nickel (5.8%), sulfur (4.5%), and less than 1 % consists of trace elements.
INTERNAL STRUCTURE: The interior of the Earth, like that of the other terrestrial planets, is divided into layers by their chemical composition or physical properties (rheological) properties, but unlike the other terrestrial planets, it has a different inner and outer core. Its outer layer is a solid crust silicate, chemically distinct, under which there is a high viscosity solid mantle. The crust is separated from the mantle discontinuity Mohorovičić, varying the thickness of the same from an average of 6 km in the oceans between 30 and 50 km on the continents. The crust and the upper cold and rigid upper mantle are commonly known as the lithosphere, and it is of the lithosphere that the tectonic plates are comprised. Below the lithosphere is the asthenosphere, a layer of relatively low viscosity of the lithosphere floats. Within the mantle, between 410 and 660 km below the surface, significant changes in the crystal structure. These changes create a transition zone that separates the upper and lower part of the mantle. Under the mantle is a liquid outer core of extremely low viscosity, resting on a solid inner core. The inner core may rotate at an angular velocity slightly greater than the rest of the world, moving from 0.1 to 0.5 ° per year.
CHEMICAL COMPOSITION: The mass of the Earth is approximately 5.98 × 1024 kg. (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8% It is composed mainly of iron ), calcium (1.5%) and aluminum (1.4%), with the remaining 1.2% consisting of small amounts of other elements. Because mass segregation, it is believed that the core region is mainly composed of iron (88.8%), with small amounts of nickel (5.8%), sulfur (4.5%), and less than 1 % consists of trace elements.
INTERNAL STRUCTURE: The interior of the Earth, like that of the other terrestrial planets, is divided into layers by their chemical composition or physical properties (rheological) properties, but unlike the other terrestrial planets, it has a different inner and outer core. Its outer layer is a solid crust silicate, chemically distinct, under which there is a high viscosity solid mantle. The crust is separated from the mantle discontinuity Mohorovičić, varying the thickness of the same from an average of 6 km in the oceans between 30 and 50 km on the continents. The crust and the upper cold and rigid upper mantle are commonly known as the lithosphere, and it is of the lithosphere that the tectonic plates are comprised. Below the lithosphere is the asthenosphere, a layer of relatively low viscosity of the lithosphere floats. Within the mantle, between 410 and 660 km below the surface, significant changes in the crystal structure. These changes create a transition zone that separates the upper and lower part of the mantle. Under the mantle is a liquid outer core of extremely low viscosity, resting on a solid inner core. The inner core may rotate at an angular velocity slightly greater than the rest of the world, moving from 0.1 to 0.5 ° per year.
EVOLUTION OF LIFE
At present, Earth provides the only example of an environment that has led to the evolution of life. It is believed that high energy chemical processes produced a self-replicating molecule around 4 billion years ago, and between 3500 and 3.8 billion years ago the last common ancestor existed universal. the development of photosynthesis allowed the living recogiesen energy directly from the Sun; the resulting oxygen accumulated in the atmosphere ozone layer formed (a form of molecular oxygen [O3]) in the upper atmosphere. The incorporation of smaller within larger cells resulted in the development of complex cells called eucariotas.43 True multicellular organisms formed as cells within colonies became increasingly specialized. Life colonized the surface of Earth in part by the absorption of ultraviolet radiation by the layer ozono.
In the 1960s a hypothesis which states that during the Neoproterozoic period, from 750 to 580 Ma, there was intense glaciation in which much of the planet was covered by an ice sheet emerged. This hypothesis has been termed the "global glaciation", and is of particular interest since this event preceded the so-called Cambrian explosion in which multicellular life forms began to proliferar.
In the 1960s a hypothesis which states that during the Neoproterozoic period, from 750 to 580 Ma, there was intense glaciation in which much of the planet was covered by an ice sheet emerged. This hypothesis has been termed the "global glaciation", and is of particular interest since this event preceded the so-called Cambrian explosion in which multicellular life forms began to proliferar.
lunes, 6 de octubre de 2014
PLANET EARTH
Planet earth .. is a planet in the Solar System that orbits its star-the Sun in the third innermost orbit. It is the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the four terrestrial.
The Earth was formed about 4.55 billion years ago and life began about a billion years después.16 is home to millions of species, including humans and currently the only astronomical body where it is known the existence of life.17 The atmosphere and other abiotic conditions have been significantly altered the planet's biosphere, favoring the proliferation of aerobic organisms as well as the formation of an ozone layer which, together with Earth's magnetic field block harmful solar radiation, thus allowing life on Earth.
The Earth was formed about 4.55 billion years ago and life began about a billion years después.16 is home to millions of species, including humans and currently the only astronomical body where it is known the existence of life.17 The atmosphere and other abiotic conditions have been significantly altered the planet's biosphere, favoring the proliferation of aerobic organisms as well as the formation of an ozone layer which, together with Earth's magnetic field block harmful solar radiation, thus allowing life on Earth.
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