Wednesday, November 27, 2019

birth and death of a star essays

birth and death of a star essays 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 collision between giant molecular clouds or entry onto galactic spiral arms. Both of these occurrences set up compression waves within the cloud, which cause isolated regions to become so dense that gravity overwhelms all other processes and the could collapses. These isolated regions can often contain enough mass to create several hundred stars of similar mass to the sun. They are known as Barnard objects, and often appear as black regions in front of stars. Sometimes regions with emission nebulas reach the appropriate density and collapse. These appear as round, black bubble within the glowing gas. They are referred to as Bok globules. As Barnard objects and Bok globules collapse, isolat...

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