The Ata-Puerca Mountains is an ancient landscape Region of Spain, formed by the dissolution of Soluble Rocks such as Lime-Stone, Dolomite, and Gypsum. It is characterized by underground drainage system with Sink-holes, Dolines, and Caves. The Region belongs to the Province of Burgos, Castille and Leon and near Ata-Puerca and Ibeas de Juarros.
It contains several Caves, where fossils and stone tools of the earliest known Humans in Western Europe have been found. They have been dated as being up to 1.2 million and 600 thousand years old, respectively. The Caves are known collectively as the "Archaeological Site of Ata-Puerca."
Larger Brain cases with a cranial volume of 1100-1400 cm3 overlapping the 1350 cm3 average of modern humans, were found in the caves belonging to that specific Region.
Numerous fossil bones indicate that some of them were giants (2.13m/7ft tall). Recent findings in a pit in Ata-Puerca suggest they were the 1st species of humans who bury its dead. They acquired a pre-linguistic system of communication. No form of art have been uncovered, although red ochre (mineral used to mix red pigment useful as a paint) were found in other Caves of the Region.
The morphology of the outer and middle ear suggest they had an extraordinary auditory sensitivity. They were able to differentiate between many different sounds.
In antiquity, the Ebro was used as the dividing line between Roman (North) and Carthaginian (South) expansions after the 1st Punic War (264-241 BC). When Rome, fearful of Hannibal's growing influence in The Iberian Peninsula, made the City of Saguntum (South of Ebro) a Protectorate of Rome. Hannibal viewed it as a Treaty Violation and as an aggressive action by Rome and used the event as the catalyst to the Second Punic War.
The Ebro is the most important River in Spain in terms of length, 928 km (577mi). The flow decreased notably by about 29 per cent during the 20th century due to the construction of Dams, low rain fall, increasing demands for irrigation due to high sunshine and strong and dry winds, and the evaporation from reservoirs in the river basin. Dams and hydraulic canalization altered the dynamic of the River forever. This situation had a direct impact on the deltaic system at the mouth of the river because its hydrological dynamics are mainly controlled by the River discharge. The decrease in River discharge has meant introduction of the Salt Wedge. Fresh water floats on top of the sea-water in a layer that gradually thins as it moves Seaward. The denser Sea Water moves landward along the bottom of the estuary. As a velocity difference develops between the two layers, shear forces generate internal waves at the interface, mixing the Sea-Water upward with the Fresh-Water. The sediment load was reduced by more than 99 per cent during the last century. The drastic reduction in sediment transport implies a sediment deficit in the Delta, which is causing the erosion of the Coast-Line and lack of sediment replenish. Due to this changes almost entire forested area were cleared for crops or for pulp-wood forest plantation. Numerous plant and animal species have disappeared.
The traditional local Administrative Division (Comarca) named La Bureva is located in the NorthEast of the Province of Burgos in the autonomous community of Castilla and Leon.
La Bureba Pass connects the Ebro River Valley leading to the Mediterranean Sea and the duero Valley leading to that River's outlet at the Atlantic Ocean. This conjunction results in a transition area between two Biomes that is a gradual blending of two communities rich in species derived from both ecosystems. The Pass was part of a Roman Cause-Way of the pilgrimage route known as Pilgrim Ways (Camino Frances) to the shrine of the Apostle James the Great in the catedral of Santiago de Compostela in Galicia in North-Western Spain, where tradition said that the remains of the Apostle are buried in there. Many take up this route as a form of Spiritual Path or retreat for their spiritual growth.
The location of the Archaeological Site of Ata-Puerca between 2 major Water-Sheds and its importance Mountain Pass explain the intensity and continuity of human habitation found there.
The Sites in this Region were found during the construction of Railway cuts through Grand Dolina, Galery, and Elephant, and the cut through the Cave of the "Bone Hill"(Sima de los Huesos).
Because of its importance, in 2000, the Archaeological Site of Ata-Puerca was added to the Unesco list of World Heritage Sites.
The World's largest Landscape made of Soluble Rocks is Australia's Nul-Arbor Plain. Slovenia has the World's highest risk of Sink-Holes, while the Western High-Land Rim in the Eastern United States is at the second-highest risk of Soluble Rocks Sink-Holes.
Wednesday, March 2, 2016
WHY ASTEROIDS IMPACT THE EARTH?
For millennia people have wondered about the unpredictable behaviour of Comets, Meteors and Asteroids in the Sky. As far as we know, the German Mathematician and Geographer Peter Apian (Petrus Apianus) was the 1st to postulate, in 1540, that a Cometary Tail always point away from the Sun. In 1619 Kepler suggested that this is because the light of the Sun exerts a Repulsive Force on the particles of the Cometary Tail. Keppler was the first to speculate on this "light pressure."
The depression named Nord-Linger Ries is a large circular depression in Western Bavaria, Germany, located North of the Danube in the now District of Donau-Ries.
The depression is interpreted as a major Meteor Impact Crater formed about 14 million years ago. The original crater rim had an estimated diameter of 24 km (15mi). The present floor of the depression is about 100 to 150m (330 to 490ft) below the eroded remains of the rim. The key evidence was the presence of Coesite, which, in none metamorphosed rocks, can only be formed by the shock pressures associated with meteorite impact.
Another impact crater, the much smaller (3.8km diameter) crater, is located about 42km(26mi) West-Southwest from the centre of Ries. The two craters are believed to have formed nearly simultaneously by the impact of a binary asteroid.
A binary asteroid is a system of two asteroids orbiting their common center of mass or the point around which they both orbit. Recent work suggests that most of them have a significant macro-porosity (a "rubble-pile" interior), and may have formed by disruption of a parent body after an oblique impact or fission.
Recent computer modelling of the Impact Event indicated that the impactors had diameters of about 1.5km (4900ft) (Larger One) and 150m (490ft) (Smaller One). They had a pre-impact separation of some tens of kilometers, and impacted the targeting area at an angle around 30 to 50 degrees from the surface in a West-SouthWest to East-NorthEast direction. The impact velocity is thought to have been about 20km/s (45000mph). The resulting explosion had he power of 1.8 million Hiroshima Bombs, an energy of roughly 2.4x10(x21) Joules.
Ivan Osipo-Vich Yarkov-Sky (24 May 1844-22 January 1902) was a Polish civil engineer working in Russia. By day, he was employed by the Alexand-Rovsk Railway company Moscow-Brest. He was obscure in his own time. In his spare time, he went deeply into the Physical Sciences and searched for a "Grand Theory" of the Physical World. In1888 he described a subtle Thermal Effect that he believed would act on planets and smaller objects orbiting the Sun. Writing in a pamphlet around the year 1900, he noted that the Diurnal Heating of a Rotating Object in Space would cause it to experience a Force that, while tiny, could lead to large long-term effects in the Orbits of Small Bodies, especially meteoroids and asteroids. This effect fell into oblivion. In 1950, longer after his death, his work on the Effects of Thermal Radiation on small objects in the Solar System (Asteroids) was re-discovered and now is so-called Yarkov-Sky Effect in Planetary Astronomy.
The effect is a consequence of the Fact that change in the temperature of an object warmed by radiation (and therefore the intensity of Thermal Radiation from the Object) lags behind changes in the incoming radiation. The surface of the object takes time to become warm when first illuminated; and takes time to cool down when illumination stops.
The Diurnal Effect on a rotating body illuminated by the Sun (e.g. an asteroid or the Earth) is that the surface is warmed by Solar Radiation during the day, and cools at night. Due to the Thermal Properties of the Surface, there is a lag between the absorption of Radiation from the sun, and the Emission of that same Radiation as Heat, so the warmest point on a rotating body occurs around 2 PM site on the surface, or slightly at Noon. This results in a difference between the directions of Absorption and Re-emission of Radiation, which yield a Net Force along the Direction of Motion of the Orbit. If the Object is a pro-grade rotator, the Force is in the direction of motion of the orbit, and causes the Semi-Major Axis of the Orbit to increase steadily; the Object spirals away from the Sun. A retro-grade rotator spirals inward. The Diurnal Effect is the component for Bodies with diameter greater than about 100 m.
The Seasonal Effect is the easiest to understand for the case of a non-rotating orbiting the Sun, for which Each Year consists of exactly One Day. As it travels around its orbit, the "Dusk" Hemisphere which has been heated over a long preceding time period is invariable in the direction of Orbital Motion. The excess of Thermal Radiation in this direction causes a Breaking Force which always causes Spiraling Inward toward the Sun.
In practice, for Rotating Bodies, the Seasonal Effect increases along with the Axial Tilt. It dominates only if the Diurnal Effect is small enough. This may occur because of very rapid Rotation (no time to cool off on the Night Side, hence an almost uniform longitudinal temperature distribution), small size (the whole body is heated throughout) or an Axial Tilt close to 90 degrees.
The Seasonal Effect is more important for smaller Asteroid Fragments (from a few metres up to about 100m), provided their surfaces are not covered by an insulating layer of loose, heterogeneous superficial material, and they do not have exceedingly slow Rotations. Additionally, on very long time-scales over which the Spin Axis of the Body may be repeatedly changed due to collisions (and hence also the direction of the Diurnal Effect changes), the Seasonal Effect will also tend to dominate.
In general, the effect is size dependent, and will affect the semi-major Axis of smaller asteroids, while leaving large asteroids practically unaffected.
The depression named Nord-Linger Ries is a large circular depression in Western Bavaria, Germany, located North of the Danube in the now District of Donau-Ries.
The depression is interpreted as a major Meteor Impact Crater formed about 14 million years ago. The original crater rim had an estimated diameter of 24 km (15mi). The present floor of the depression is about 100 to 150m (330 to 490ft) below the eroded remains of the rim. The key evidence was the presence of Coesite, which, in none metamorphosed rocks, can only be formed by the shock pressures associated with meteorite impact.
Another impact crater, the much smaller (3.8km diameter) crater, is located about 42km(26mi) West-Southwest from the centre of Ries. The two craters are believed to have formed nearly simultaneously by the impact of a binary asteroid.
A binary asteroid is a system of two asteroids orbiting their common center of mass or the point around which they both orbit. Recent work suggests that most of them have a significant macro-porosity (a "rubble-pile" interior), and may have formed by disruption of a parent body after an oblique impact or fission.
Recent computer modelling of the Impact Event indicated that the impactors had diameters of about 1.5km (4900ft) (Larger One) and 150m (490ft) (Smaller One). They had a pre-impact separation of some tens of kilometers, and impacted the targeting area at an angle around 30 to 50 degrees from the surface in a West-SouthWest to East-NorthEast direction. The impact velocity is thought to have been about 20km/s (45000mph). The resulting explosion had he power of 1.8 million Hiroshima Bombs, an energy of roughly 2.4x10(x21) Joules.
Ivan Osipo-Vich Yarkov-Sky (24 May 1844-22 January 1902) was a Polish civil engineer working in Russia. By day, he was employed by the Alexand-Rovsk Railway company Moscow-Brest. He was obscure in his own time. In his spare time, he went deeply into the Physical Sciences and searched for a "Grand Theory" of the Physical World. In1888 he described a subtle Thermal Effect that he believed would act on planets and smaller objects orbiting the Sun. Writing in a pamphlet around the year 1900, he noted that the Diurnal Heating of a Rotating Object in Space would cause it to experience a Force that, while tiny, could lead to large long-term effects in the Orbits of Small Bodies, especially meteoroids and asteroids. This effect fell into oblivion. In 1950, longer after his death, his work on the Effects of Thermal Radiation on small objects in the Solar System (Asteroids) was re-discovered and now is so-called Yarkov-Sky Effect in Planetary Astronomy.
The effect is a consequence of the Fact that change in the temperature of an object warmed by radiation (and therefore the intensity of Thermal Radiation from the Object) lags behind changes in the incoming radiation. The surface of the object takes time to become warm when first illuminated; and takes time to cool down when illumination stops.
The Diurnal Effect on a rotating body illuminated by the Sun (e.g. an asteroid or the Earth) is that the surface is warmed by Solar Radiation during the day, and cools at night. Due to the Thermal Properties of the Surface, there is a lag between the absorption of Radiation from the sun, and the Emission of that same Radiation as Heat, so the warmest point on a rotating body occurs around 2 PM site on the surface, or slightly at Noon. This results in a difference between the directions of Absorption and Re-emission of Radiation, which yield a Net Force along the Direction of Motion of the Orbit. If the Object is a pro-grade rotator, the Force is in the direction of motion of the orbit, and causes the Semi-Major Axis of the Orbit to increase steadily; the Object spirals away from the Sun. A retro-grade rotator spirals inward. The Diurnal Effect is the component for Bodies with diameter greater than about 100 m.
The Seasonal Effect is the easiest to understand for the case of a non-rotating orbiting the Sun, for which Each Year consists of exactly One Day. As it travels around its orbit, the "Dusk" Hemisphere which has been heated over a long preceding time period is invariable in the direction of Orbital Motion. The excess of Thermal Radiation in this direction causes a Breaking Force which always causes Spiraling Inward toward the Sun.
In practice, for Rotating Bodies, the Seasonal Effect increases along with the Axial Tilt. It dominates only if the Diurnal Effect is small enough. This may occur because of very rapid Rotation (no time to cool off on the Night Side, hence an almost uniform longitudinal temperature distribution), small size (the whole body is heated throughout) or an Axial Tilt close to 90 degrees.
The Seasonal Effect is more important for smaller Asteroid Fragments (from a few metres up to about 100m), provided their surfaces are not covered by an insulating layer of loose, heterogeneous superficial material, and they do not have exceedingly slow Rotations. Additionally, on very long time-scales over which the Spin Axis of the Body may be repeatedly changed due to collisions (and hence also the direction of the Diurnal Effect changes), the Seasonal Effect will also tend to dominate.
In general, the effect is size dependent, and will affect the semi-major Axis of smaller asteroids, while leaving large asteroids practically unaffected.
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