birth and death of a star
The night sky, unimaginably deep, is a breathtaking sight. Some three thousand stars can be seen with the naked eye, twinkling points of light that have inspired the human spirit since the dawn of time. Study of the stars, based on data collected from visible-light telescopes, radio telescopes, and detectors wavelengths can now reveal extraordinary amounts of information: size, temperature, chemical composition, internal structure, distance and rotation rate, among other factors. One of the most important discoveries that scientists and astronomers have made is mapping out the life cycle of a star. Little by little, they have discovered all the different stages of a star; from its birth to its eventual death. As giant molecular clouds orbit the center of a galaxy, they are tugged by gravitational and magnetic fields. How fast their constituent particles move depends on their temperatures: the colder the cloud, the slower the particles. Fast moving particles resist collapsing together, and so stars can form only in the dense cores of cold clouds. Typically, these clouds are only about 15 degrees above absolute zero. Periodically, the clouds begin to collapse. The trigger mechanisms for such collapses are thought to be
Although there are no nuclear processes going on within the protostar, it is still giving off energy from the material that is striking its surface. This is given off as radiation but is very quickly absorbed by the dusty envelope raining down on the surface of the protostar. This action heats the dust, which then re-radiates the energy at infrared wavelengths. The envelope that surrounds the envelope is vast; typically, it is 20 times larger than out entire solar system. collision between giant molecular clouds or entry onto galactic spiral arms. As the star crashes down upon itself, it releases so much energy that it explodes and virtually blows itself to bits. This is known as a supernova. The energy released in supernova explosions initiates the production if the elements heavier than iron. Stars that explode in this way are called supernovas, type II. Type I supernova involve white dwarf stars. If a white dwarf star is close enough to another star, that star can transfer some of its outer atmosphere onto the white dwarf. This builds up on the white dwarf until a catastrophic nuclear detonation tales place. This can destroy the white dwarf and produce a supernova type I. Iron builds up in the core of the star and does not fuse into anything else. This is because all of the nuclear fusion processes so far have released energy but, after iron, the energy needed to fuse elements together is greater than the energy released in the fusion process. There is nowhere for that energy to come from, and so the iron accumulates in an electron-ddgenerate mass at the center of the star. The electron pressure is not infinite, however and as the mass gradually builds up, the core begins to become unstable. When the mass contained in the core reaches just under on
Some common words found in the essay are:
, Ophichus VLA, II Type, Sun Chandrasekhar, white dwarf, Becklin- Neugubauer, carbon fusion, isolated regions, heavier elements, giant molecular clouds, protostar material, bok globules, builds core, star begins, nuclear fusion, molecular clouds,
Approximate Word count = 1203
Approximate Pages = 5 (250 words per page double spaced)
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