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
Sometimes regions with emission nebulas reach the appropriate density and collapse. The Universe is composed of 75% hydrogen and 23% helium; heavier elements make up the remaining 2%. They are referred to as Bok globules. The rest is nearly all helium with 2 percent being made up of the heavier elements. This is given off as radiation but is very quickly absorbed by the dusty envelope raining down on the surface of the protostar. Stars that explode in this way are called supernovas, type II. The envelope that surrounds the envelope is vast; typically, it is 20 times larger than out entire solar system. The silicon burning, which produces the iron core, usually takes place within a mere day or two. It is the smaller-scale collapses from which stars form. The first, young infrared star to be found was discovered in the Orion star-forming region. The shock waves from the supernova explosion are one of the mechanisms by which the interstellar medium is compressed and thus new stars formed. The overlying structure, in this case the rest of the star, begins to collapse downward. This raises the temperature even more. Hydrogen fusion takes place in the outermost shell of the core region and below that, helium is converted to carbon and oxygen. As the star crashes down upon itself, it releases so much energy that it explodes and virtually blows itself to bits.
Common topics in this essay:
,
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,
|
Acceptance Essays
