Miyerkules, Oktubre 12, 2011

Theories of the origin of universe

                                                     
  The Steady State Universe Theory Originated by *Fred Hoyle in 1948, this theory says that, in the space between galaxies, new matter is quietly but continually appearing out of nothing. In 1965, Hoyle publicly abandoned the theory as ridiculous.
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The Oscillating Universe Theory This is another idea by *George Gamow. It says that when the universe finally runs down, another Big Bang will start it going again. The main difference is that, while the first Bang occurred when nothing exploded into all the matter in the universe, the later ones would be the result of all the matter packing into a tiny point and then exploding again.
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The Nebular Hypothesis (also called the Planetesimal Theory) says that, as the gas swirled around, eddies of gas caused the sun and planets. All seven theories require circling gas which contracts into the sun. We have already disproved the basics underlying this concept. Many say that material from the sun made the planets and moons. But the elemental composition of each of the planets is different from the sun and from one another. One could not come from the other. In addition, the sun would have to rotate extremely fast to hurl off planets and moons, yet it rotates very slowly. More on this later.
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The Fision Theory says that our sun burst and sent out the planets and moons. But they would fly outward forever; they would not stop and begin circling the sun or one another.
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The Capture Theory says our planets and moons were wandering around and were captured by our sun. But they would then crash into the sun; they would not circle it or one another. We never see planets or moons flying by us today, yet we now know of at least 150 moons in our solar system (Jet Propulsion Laboratory, 2006).
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The Accretion Theory says that small chunks of material gradually got together and formed our planet. Then more chunks formed our moon, which began circling us. This idea is pretty far out also. The planets, moons, and asteroids are all in carefully arranged orbits. The meteors fly fast in linear motion. No chunks are just floating around, and those chunks would not stick together anyway.
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The Planetary Collision Theory says our world collided with a small planet, producing our moon. But such an impact would totally destroy our planet. How could such an impact produce a circling moon? This would have had to be repeated for all 150 moons in our solar system. The theory would require thousands of planets passing through our solar system, for enough direct hits to produce all our moons. Why are not such flybys occurring today?
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The Stellar Collision Theory says that two stars collided, and produced our planets and moons. But they would not then pause and circle one of the suns which was waiting placidly to receive them. They would either be hurled away from the sun or crash back into it.
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The Gas Cloud Theory says gas clouds were pulled in from outer space by our sun's gravity; then they paused, formed themselves into planets and moons, and began circling one another. But gas does not clump, and linear motion toward the sun would not change into circular motion around it.
The Big Bang Theory holds that everything in the universe, stars, galaxies, radiation, interstellar gas, everything was created in one huge explosion. Since that time all of the matter in the universe is hurtling outward at speeds that increase with the distance from the site of the explosion, and which approach the speed of light for the most distant objects.
       There are several versions of the Big Bang Theory, but in its purest form, all the matter and energy in the universe suddenly sprang into existence at some point estimated to be about 13.5 billion years ago. This matter and energy instantaneously came into being, forming a mass no bigger than a proton. Prior to that instant, nothing existed, no matter, no energy, not even empty space or time itself.
       The Big Bang Theory explains the red shift, and also some of the background radiation that has been observed. But it explains little else. In particular, it fails to explain why the matter in the universe is distributed so unevenly.




Planets of the Solar System

SUN
                                              SUN

            The sun is the center of the solar system and a star.It is consist of hot plasma interwoven with magnetic fields with its diameter is about 1,392,000 km and almost perfectly spherical. It is 109 times that of Earth, and its mass (about 2×1030 kilograms, 330,000 times that of Earth) accounts for about 99.86% of the total mass of the Solar System. Chemically, about three quarters of the Sun's mass consists of hydrogen, while the rest is mostly helium. Less than 2% consists of heavier elements, including oxygen and others.

                                         MERCURY   

        Mercury is the smallest planet in our solar system. Mercury is about the same size as our Moon. It is very close to the Sun. Mercury travels around the Sun faster than any other planet. That is how it got its name. It was named after Mercury, the swift messenger of the gods in ancient Roman mythology. Mercury can only be seen from Earth just before sunrise or just after sunset, but not in the middle of the night. That is because Mercury always appears near the Sun when viewed from Earth. Mercury has a very thin atmosphere. Humans would not be able to live there. The surface of Mercury has holes in it where objects such as meteorites and asteroids crashed into it.
                                                                                                   VENUS
           Venus is the second planet from the sun and passes closer to the Earth than any other planet at a minimum distance of 108 million km. It can reach magnitudes of -4.7, which is much brighter than the next planet, Jupiter. This is because of its dense atmosphere, which reflect about 65% of the light hitting them.
                   




                                               EARTH
Earth is our home; the third planet from the Sun. It orbits the Sun at an average distance of 150 million km. Earth is the only planet in the Solar System known to support life. This is because our atmosphere keeps the planet warm from the vacuum of space, but it’s not so thick that we have a runaway greenhouse effect. The Earth has a solid core of iron surrounded by a liquid outer core that generates a magnetic field that also helps protect life on Earth from the radiation of space.
                                              MARS
 The 4th planet from the Sun is Mars, the second smallest planet in the Solar System. It orbits the Sun at an distance of 228 million km. You might think Mars is large, but it’s a tiny world, with about half the diameter of Earth, and just 1/10th the Mass. If you could stand on the surface of Mars, you’d experience about 1/3rd Earth’s gravity. Mars has almost no atmosphere to help trap heat from the Sun, and so temperatures can plunge below -140 °C in the Martian winter. Even at the height of summer, temperatures can get up to 20 °C in the day – just barely shirt sleeve weather.
                                           JUPITER
Mighty Jupiter is the biggest planet in our Solar System. It’s so large, in fact, that it has 2.5 times the mass of all the rest of the planets in the Solar System combined. Jupiter orbits from the Sun at an average distance of 779 million km. Its diameter at the equator is 142,984 km across; you could fit 11 Earths side by side and still have a little room. Jupiter is almost entirely made up of hydrogen and helium, with trace amounts of other elements.


                                           SATURN
Saturn is the 6th planet from the Sun, and the 2nd largest planet in the Solar System. It orbits the Sun at an average distance of 1.4 billion km. Saturn measures 120,000 km across; only a little less than Jupiter. But Saturn has much less mass, and do it has a low density. In fact, if you had a pool large enough, Saturn would float!                                                       


                                             URANUS
Next comes Uranus, the 7th planet from the Sun. It orbits the Sun at an average distance of 2.9 billion km. Uranus measures 51,000 km across, and is the 3rd largest planet in the Solar System. While all of the planets are tilted on their axes, Uranus is tilted over almost on its side. It has an axial tilt of 98°. Uranus was the first planet to be discovered with a telescope; it was first recognized as a planet in 1781 by William Herschel. 

                                                                                                   NEPTUNE
Neptune is the 8th and final planet in the Solar System, orbiting at an average distance of 4.5 billion km from the Sun. It’s the 4th largest planet, measuring about 49,000 km across. It might not be as big as Jupiter, but it’s still 3.8 times larger than Earth – you could fit 57 Earths inside Neptune. Neptune is the second planet discovered in modern times. It was discovered at the same time by both Urbain Le Verrier and John Couch Adams.