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Monday, April 18, 2011

Supernova Research Paper

Supernova Research Paper

In 1572, the Danish astronomer Tycho Brahe was witness to one of the most exciting cosmic phenomena known to exist -- a supernova, or gigantic stellar explosion. Little did he know that this same supernova “which now bears his name” would be so well-studied in later years that astronomers would know such intricate details as its chemical composition. Today the still-brilliant remnants of the Tycho supernova, which is located in the constellation Cassiopeia, has two major observers - the European XMM-Newton telescope and the NASA Chandra X-ray Observatory. These telescopes have, in a matter of months, already uncovered a wealth of data about the exploded star. Most recently, the European telescope has detailed the composition of Tycho, identifying in the supernova remnant many of the same chemical building blocks used to make the planets and life on Earth. Supernovae are some of the most violent events in the universe. They occur at the end of a giant star's life, when the star has used up all of its nuclear fuel. When that happens, the stellar core collapses in on itself, releasing huge amounts of energy into the local interstellar space around it in a giant explosion.
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Tycho Brahe was witness to one of the only three or four supernovae known to explode during human history. Though today the Tycho supernova is visible only through a telescope, at the time of its initial blast it was visible to the naked eye for about 18 months. In fact, the initial explosion probably appeared as one of the brightest stars in the sky. Today, astronomers are not studying visible light from the supernova, as Tycho would have seen it, but rather its X-ray light, which can be detected by both XMM-Newton and Chandra.

Scientists are interested in supernovae because they are thought to be great cosmological chefs. Most of the chemicals in the universe are created as a direct result of supernova explosions. "They're basically big cookers," said Richard Mushotsky, an XMM project scientist at NASA's Goddard Space Flight Center. "They cook the original elements like hydrogen and helium and they make them into all the stuff that we learned about in chemistry class “carbon, nitrogen, iron, etc."

"We astronomers are fond of saying that every atom we exist of once-upon-a-time lived in the center of a star that exploded like this," added Mushotsky. "So what both XMM and Chandra are able to do with exquisite accuracy is actually measure and map these elements."

But what about the heavier elements such as gold and platinum? The answer may lie in yet another of the more violent events in the Universe: collisions between superdense neutron stars. "Probably many of the heavy elements we're familiar with on Earth were made in this way," says Stephan Rosswog of the University of Leicester.

Shortly after the big bang, the Universe contained only the light elements, hydrogen and helium. When these materials later formed stars, heavier elements such as carbon and oxygen were forged in the stars' nuclear furnaces. And even heavier elements were created when very massive stars exploded as supernovae. Such explosions also blast debris into space where another generation of stars and planets form, but when it comes to the heaviest elements, such as gold and platinum, astronomers are not sure that supernovae can create enough of them. Most of these metals must be made in a nuclear reaction called the 'reprocess", in which a nucleus consumes many neutrons in quick succession. 'You would need much more extreme conditions than you get in supernova simulations," says Rosswog. He suspected the reprocess might flourish during collisions between neutron stars, the collapsed remains of stellar cores left behind after some supernova explosions. Sometimes two neutron stars orbit each other, and they can spiral ever closer together before eventually merging in a violent explosion. These mergers are rare, probably happening about once every 100,000 years in our Galaxy.

To test the idea, Rosswog's team simulated the collision of two neutron stars on a supercomputer at the University of Leicester, taking account of everything from the laws of quantum physics to Einstein's theory of general relativity. The merged stars collapsed to form a black hole, but in the process they spewed out quantities of very hot, dense, neutron-rich ash in which the reprocess could thrive. Rosswig told the National Astronomy Meeting held in Cambridge shortly after his simulation that neutron star mergers could easily produce the amount of heavy elements we see. "Right now, they're the best candidate for these elements," he says. He plans to look at the distribution of the heaviest elements in old populations of stars. Because neutron star collisions are so rare, there should be an uneven distribution of these heavy elements in the early Universe. "There should be some clumpiness," says Rosswog. However, Stan Woosley of the University of California at Santa Cruz doesn't think it's a closed case yet. "People still don't know just how and where the r-process happens," he says. "The new calculations make merging neutron stars more attractive but will not put the issue to rest." Woosley favours an alternative scenario in which, under the right conditions, supernova explosions could leave behind neutron stars that spout jets of neutrons into space. These might fuel enough reprocess reactions to build up the amounts of heavy elements we see.

So in conclusion, space science isn't just for the astronauts, and interest in space research shouldn't be limited to trekkies and rocket scientists, because space is where the basic building blocks of life were formed, and through the advancement of technology we are now able to more fully understand where the elements of our existence come from.

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Warning!!! All free online research papers, research paper samples and example research papers on Supernova topics are plagiarized and cannot be fully used in your high school, college or university education.

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