Across the horizon: the rising sun and endless possibilities
 
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Reports & Essays: Science - Earth

"AND""OR"

Stars
Stars are huge balls of glowing gas in the sky. The closest star to the earth to look like a ball is the sun. The other stars are too far away and only look like pinpoints of light. A star consists of two gases -- hydrogen and helium. The star shines because atomic energy makes these gases very hot. When it runs out of hydrogen gas, the star may explode into a huge cloud of gas and dust. Astronomers believe that most stars have enough hydrogen to last billions of years. A star manages to avoid collapsing because of the equilibrium achieved by itself. The gravitational pull from the core of the star is equal to the gravitational pull of the gases, forming a type of orbit. When this equality is broken, the star can go into several different stages. Usually if the star is small in mass, most of the gases will be consumed while some of it escapes. This occurs because there is not a tremendous gravitational pull upon those gases and therefore the star weakens and becomes smaller. It is then referred to as a White Dwarf. If the star was to have a larger mass however, then it may possibly Supernova, meaning that the nuclear fusion within the star simply goes out of control causing the star to explode. After exploding, a fraction of the star is usually left (if it has not turned into pure gas) and that fraction of the star is known as a Neutron Star. A black hole is one of the last option that a star may take. If the core of the star is so massive, (approximately 6-8 solar masses; one solar mass being equal to the sun's mass), then it is probable that when the star's gases are almost consumed those gases will collapse inward. They would be forced into the core by the gravitational force laid upon them. After a black hole is created, the gravitational force continues to pull in space debris and other type of matters to help add to the mass of the core, making the hole stronger and more powerful. Most black holes tend to be in a consistent spinning motion. The action absorbs various matter and spins it within the ring (known as the Event Horizon) that is formed around the black hole. The matter keeps within the Event Horizon until it has spun into the center where it is concentrated within the core adding to the mass. Such spinning black holes are known as Kerr Black Holes. Most black holes orbit around stars which may cause some problems for the neighboring stars. If a black hole gets powerful enough it may actually pull a star into it and disrupt the orbit of many other stars. The black hole could then grow even stronger (from the star's mass) as to possibly absorb another. When a black hole absorbs a star, the star is first pulled into the Ergosphere. From there, it is swept into the Event Horizon, named for its flat horizontal appearance. This is the place where all the action within the black hole occurs. When the star reaches the Event Horizon, its light is bent within the current and therefore cannot be seen in space. At this point, high amounts of radiation are given off, and with the proper equipment it can be detected and seen as an image of a black hole. Using this technique astronomers now believe that they have found a black hole known as Cygnus X1 which appears to have a huge star orbiting around it. The first scientists to really take an in depth look at black holes and the collapsing of stars were Professor Robert Oppenheimer and his student Hartland Snyder in the early 1900's. They concluded, on the basis of Einstein's theory of relativity, that if the speed of light was the utmost speed over any massive object, then nothing could escape a black hole once it is in its clutches. (1) The name "black hole" was coined because light could not escape from the gravitational pull from the core, thus making the black hole impossible for humans to see it without using a technical device for measuring such things like radiation. The second part of the word, "hole", was used because it is the spot where everything is absorbed and where the center core presides. This core is the main part of the black hole where the mass is concentrated and appears purely black on all readings even when using radiation detection devices. Just recently a major discovery was found with the help of a device known as The Hubble Telescope. This telescope has just recently found what many astronomers believe to be a black hole, after being focused on an star orbiting empty space. Several picture were sent back to Earth from the telescope showing many computer enhanced pictures of various radiation fluctuations and other diverse types of readings that could be read from the area in which the black hole is suspected to exist. Several diagrams were made showing how astronomers believe that if somehow one were to survive within the center of the black hole, that there would be enough gravitational force to possible warp you to another end in the universe or possibly to another universe. The creative ideas that can be hypothesized from this discovery are endless. Stars appear to have different colors. They differences are caused by the temperature of their surface. The temperature varies from about 5,000 degrees F. for red stars, such as Betelgeuse, to about 50,000 degrees F. for blue stars, such as Rigel. Stars of other colors have surface temperatures somewhere in between. The sun, a yellowish star, has a temperature of about 10,000 degrees F. The brightness of a star depends on the amount of light energy that a star sends out, not on its size or its closeness to the earth. Rigel is smaller and farther from the earth than is Betelgeuse, yet Rigel sends out so much more light energy that it looks brighter than Betelgeuse. Astronomers use an instrument called a photometer, attached to a telescope, to measure the brightness of stars. When the light from a star enters the photometer, it produces an electric current in ti. An electrical meter indicates the star's brightness in terms of the strength of the current. References: (1) Parker, Barry. Colliding Galaxies. PG#96

 



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