Thursday, October 29, 2009

Formation Of Earth - An Amazing History

The theory which explain the origin of earth and this Universe is called Big Bang Theory. According to this theory all matter in the Universe was, at one time, concentrated in a giant mass (a black hole?) that blew apart about 10 to 20 billion years ago (bya) and is still expanding.

Origin of Sun:
It is thought that our solar system had its origins when, about 5 bya, triggered by some unknown cause, a cloud of interstellar dust and gases collapsed and condensed. Some of the matter in the central mass contracted under its own gravity, condensed, and heated until forces were so strong that thermonuclear reactions began, and this was the origin of our star, the Sun.

Origin of Planets:
About 4.6 to 4.5 billion year ago, a disk-shaped cloud of subsidiary smaller lumps, pieces, dust, gases, etc. orbiting the sun subsequently coalesced and condensed to form theplanets, satellites, asteroids, comets, etc.

Formation Of Atmosphere:
 It is thought that Earth began as a cold world, and the very first atmosphere may have been hydrogen gas, but since that is so light weight and very chemically reactive, most of it would have floated off into space or reacted with other substances, thus would have been rapidly dissipated. Then some other volcanic activities and other chemical reaction took place.The inner four, solid planets have started out with similar atmospheres of H2O, CO2, CO, and N2. These chemicals made up the atmosphere of our planet for the first 1 billion years, and initially, provided similar atmospheres for the other three solid planets.However, the distance of each of these planets from the sun has influenced what subsequently took place there:
  • Mercury is too close to the sun and too hot. Any water that might have been there (and any other volatile chemicals) would, long ago, have evaporated into space.
  • Venus also is too close to the sun to have any surface water. 
  • Mars, on the other hand, is too far away from the sun, and so is too cold. Any water and carbon dioxide present on the planet are frozen solid in the “ice” cap. Also, the planet is too small to hold very much atmosphere, and there is not enough of a greenhouse effect to keep the planet warm. Thus, there is essentially no atmosphere left.
But these conditions happen to be just right here on planet Earth. We are just the right distance from the sun! On Earth, the heat and the size are such that the water is neither all frozen nor all vaporized. Because liquid water is present, this has enabled formation of the lakes and oceans needed for life to evolve.

Formation of Earth Surface:
Over the next 3.5 billion years, the amount of CO2 in our atmosphere was reduced as it became incorporated into rocks (limestone is CaCO3 and forms when H2O + CO2 --> H2CO3and H2CO3 + Ca++ --> CaCO3 + 2H+). The liquid oceans formed about 3.8 billion years ago, and life has been present for nearly as long. Evidence would indicate that on early Earth, there was much more volcanic activity, many more electrical storms, and more violent and destructive meteor impacts. Because of this impact heating (and Earth’s internal heat) the Earth subsequently melted, and heavier molten materials sank to the center, forming the core, while lighter ones floated to surface and formed the crust. Thus Earth now has several layers:
  • A central core composed of very dense metals such as iron and nickle
  • The mantle, which actually consists of several layers of varying composition, and is a molten, medium density, viscous liquid
  • The crust floats on the outside. Because the minerals in the crust are cooler, they have formed strong, rocky layers collectively referred to as the lithosphere.
Origins of Life:
The atmosphere was made largely of water vapor (H2O), carbon dioxide (CO2), carbon monoxide (CO), nitrogen (N2), methane (CH4), and ammonia (NH3). As the surface of Earth cooled again, torrential rains of this mixture formed the first seas, the “primordial soup.”
1. First, organic monomers (simple sugars, amino acids, fatty acids, and nucleotides) would have to be synthesized abiotically from inorganic substances like methane, carbon dioxide, and ammonia. Around all 20 amino acids, and a number of sugars, lipids, and nucleotides have been obtained from these inorganic substances(H2O, H2, CH4 and NH3)

2. The second step would be the formation of organic polymers and genetic material from the existing monomers (polysaccharides from simple sugars, proteins from amino acids, and RNA from nucleotides), possibly using hot sand or finely divided clay as a catalyst.

3. Thirdly, it is thought that non-living aggregates of these polymers formed. These may have exhibited some properties characteristic of living organisms, but were NOT ALIVE, and did not have all the properties of living organisms. In a research laboratory, scientists have seen mixtures of proteins, lipids, and carbohydrates form globules. If the proteins involved happen to be enzymes, these globules can even carry on "metabolic" activity, although they have no means to replicate themselves. Several widely-accepted theories as to how this may have happened include the possibly involvement of damp, zinc-containing clay as a catalyst to help the nucleotides polymerize first into RNA, and later into DNA.

4. It is thought, then, that about 4.1 to 3.5 billion years ago, the first prokaryotes, like bacteria, came into existance. It is difficult to pinpoint a date for this because bacteria don't have skeletons to leave behind. The first “fossils” (remains of colonies/secretions) of prokaryotes seem to be this age. Once the first cells, the first living organisms, the first prokaryotes came into existance, then the Theory of Evolution takes over to provide an explanation for how (not why) these primitive cells diversified into the five kingdoms of life which we recognize today.
Initially, the energy needed for growth and development was supplied by glycolysis and fermentation. There was no free oxygen in the early atmosphere, and indeed, any organisms living back then would have probably been poisoned/killed by this highly-reactive chemical. Only later, as photosynthetic organisms released increasing amounts of this toxic waste into the atmosphere, did the process of cellular respiration evolve as a means of making use of this oxygen.

Friday, October 16, 2009

Leaning Tower of Pisa

The Leaning Tower of Pisa (Italian: Torre pendente di Pisa) or simply The Tower of Pisa (La Torre di Pisa) is the campanile, or freestanding bell tower, of the cathedral of the Italian city of Pisa. It is situated behind the Cathedral and is the third oldest structure in Pisa's Cathedral Square. 

The height of the tower is 55.86 m (183.27 ft) from the ground on the lowest side and 56.70 m (186.02 ft) on the highest side. The width of the walls at the base is 4.09 m (13.42 ft) and at the top 2.48 m (8.14 ft). Its weight is estimated at 14,500 metric tons (16,000 short tons). The tower has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase. Prior to restoration work performed between 1990 and 2001, the tower leaned at an angle of 5.5 degrees, but the tower now leans at about 3.99 degrees.

Leaning Tower Construction History:
The Tower of Pisa was a work of art, performed in three stages over a period of about 177 years. Construction of the first floor of the white marble campanile began on August 9, 1173, a period of military success and prosperity. This first floor is a blind arcade articulated by engaged columns with classical Corinthian capitals.
The tower began to sink after construction had progressed to the third floor in 1178. This was due to a mere three-meter foundation, set in weak, unstable subsoil, a design that was flawed from the beginning. Construction was subsequently halted for almost a century, because the Pisans were almost continually engaged in battles with Genoa, Lucca and Florence. This allowed time for the underlying soil to settle. Otherwise, the tower would almost certainly have toppled. In 1198, clocks were temporarily installed on the third floor of the unfinished construction. 
In 1272, construction resumed under Giovanni di Simone, architect of the Camposanto. In an effort to compensate for the tilt, the engineers built upper floors with one side taller than the other. This made the tower begin to lean in the other direction. Because of this, the tower is actually curved. Construction was halted again in 1284, when the Pisans were defeated by the Genoans in the Battle of Meloria.
The seventh floor was completed in 1319. The bell-chamber was not finally added until 1372. It was built by Tommaso di Andrea Pisano, who succeeded in harmonizing the Gothic elements of the bell-chamber with the Romanesque style of the tower. There are seven bells, one for each note of the musical major scale. The largest one was installed in 1655.
After a phase (1990-2001) of structural strengthening, the tower is currently undergoing gradual surface restoration, in order to repair visual damage, mostly corrosion and blackening. These are particularly strong due to the tower's age and to its particular exposure to wind and rain.

Tuesday, October 13, 2009

Bermuda Triangle - Devil's Triangle

The Bermuda Triangle, also known as the Devil's Triangle, is a region in the western part of the North Atlantic Ocean in which a number of aircraft and surface vessels are alleged to have mysteriously disappeared and cannot be explained as human error, piracy, equipment failure, ornatural disasters. Popular culture has attributed some of these disappearances to the paranormal, a suspension of the laws of physics, or activity by extraterrestrial beings..The Bermuda Triangle is inexorably associated with time travel, UFOs, missing time and wormholes. Credible witnesses to the effects of the Bermuda Triangle have been witnessed by Charles Lindbergh to Christopher Columbus. When Charles Lindbergh was making a nonstop flight from Havana to St. Louis his magnetic compass started rotating. His Earth-inductor-compass needle jumped back and forth erratically. This has now all been revealed in his autobiography. Even a great pilot like Charles Lindbergh witnessed unusual events while flying in the reaches of the Bermuda Triangle.

Area Of Triangle:
The area is one of the most heavily-sailed shipping lanes in the world, with ships crossing through it daily for ports in the Americas, Europe, and the Caribbean Islands. Cruise ships are also plentiful, and pleasure craft regularly go back and forth between Florida and the islands. It is also a heavily flown route for commercial and private aircraft heading towards Florida, the Caribbean, and South America from points north.

Bermuda Triangle Major Events

  • Flight 19 was the first incident that was heavily reported on, bringing the Bermuda Triangle into the spotlight and under speculation. In 1945, Flight 19, a small aircraft containing 5 U.S. Navy bombers set out over the sea on a training mission. The plane was being flown by an experienced pilot, and for reasons unknown to this day, just vanished. Neither the plane, nor the crew aboard was ever found.
  • As eerie as Flight 19's disappearance was, it was just a prelude to whatever happened to a Douglas DC-3 aircraft that disappeared without a trace over the Atlantic on December 28, 1948. The aircraft vanished without a trace sometime during its flight from Puerto Rico to Miami. Inexplicably, no wreckage, or any of the 32 people onboard were ever found.
  • These disappearances sparked an interest in what some were calling the Devil's Triangle.
  • Research on the area also pointed to the biggest loss of life that the U.S. Navy suffered that wasn't related to combat. On March 4, 1918, The USS Cyclops and its crew of 309 vanished without a trace sometime after leaving Barbados, an island in the Caribbean. Though many theories suggest everything from bad weather to an enemy attack, nothing has ever been proven to explain this mysterious disappearance.

Bermuda Triangle Theories:
Researchers and scientists have developed a host of theories to explain the mystery of the Bermuda Triangle. Many point to irregular and infrequent weather patterns, the Gulf Stream or rogue waves that crop up over the ocean and are difficult to predict. Other theories indicate man as the cause of the disappearances, suggesting error in reading compasses or flight tools, or even acts of violence such as piracy.
As theories may point to a natural or explainable reason for the mysteries in the Bermuda Triangle, there are other theories that point to phenomena that cannot be easily explained. Many believe that the Bermuda Triangle sits over the spot of the lost city of Atlantis. Another supernatural theory is that UFOs frequent the area over the Bermuda Triangle, and that the victims of these vanishings have been abducted by aliens.

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