Реферат на тему Supernova Research Essay Research Paper
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Supernova Research Essay, Research Paper
“There is one thing even more vital to science than intelligent methods; and that is, the sincere desire to find out the truth, whatever it may be.”
-Charles Sanders Pierce
When it comes to science, there are many questions and few answers. Finding those few answers is what makes science interesting. One big question is science is whether or not the Universe is expanding. By observing and researching supernovas, one can decide that the Universe is expanding.
The word nova means new star (Ferris 59). Early in times, a sudden increase in brightness in the sky would be considered a new star. “It wasn’t until these new stars of 1054, recorded by China, and those of 1572 and 1604, made famous by Tycho Biahe and Johannes Kepler, would now be classified as supernova (North 587). Those two famous astronomers, along with China gave supernova its name.
When supernovas were first seen they were considered to be a part of our own universe. It was because “In 1917, Albert Einstein and other physicists believed our own Galaxy was all there was to the Universe- a uniformly dense collection of stars and other matter floating in the void” (1). Einstein was regarded as one of the most brilliant men of all time. People would surely not disagree with the mighty Einstein! No one would challenge Einstein until 1929. It was then that Edwin Hubble proposed that the universe was much larger than our own galaxy. His evidence was that the galaxy light was redshifted. (1) Redshifting, for example is like “the lowered pitch of a fire truck’s siren as it races away, and that the light from more distant galaxies was redshifted farther than closer ones” (1). With Hubble’s evidence it was immediately clear that there was more to supernovas than met the eye. With this evidence in mind Einstein called his theory on the Universe, “The biggest blunder of my life.”
Knowing that there is more to our Universe than our own galaxy scientists have been able to learn many things about the stars. It was this knowledge that lead scientists to learn that the early stars “were composed of hydrogen, helium and a very small amount of lithium and beryllium and almost nothing else” (6-2) These elements laid the structure for the structure of the stars. Every star has a battle inside of it. It is a battle between gravity and radiation pressure that happens when it arises from internal energy generation. (6) Stars are seen everywhere on earth but the ones most readily observed are the exploding stars called supernova (Ferris). It is at the end of a star’s life when a supernova occurs. The stars nuclear fuel gets exhausted and it can no longer support itself. If the star is an enormous one, then the stars core will collapse. This collapse will cause a massive amount of energy. (4) Every time a supernova occurs, it burned its core elements so hot that other elements were born. “Elements like carbon, oxygen, phosphorus and iron were made more common” (6-2). A supernova happens every few seconds. They are long and sought after landfalls of knowledge. (5) “They are thought to not only reveal the stars own fate, but also the universe in its entirety” (5). Evaluating supernovas is a key element in discovering the destiny of the universe.
One of biggest and most supported groups evaluating and researching supernovas is The Supernova Cosmology Project. It is a team of scientists out of The University of California at Berkeley. One of the things that The Supernova Cosmology Project does is to look into distant past by looking at distant objects in space. (1) The objects they focus most of all are supernovas. When looking for a supernovas, astronomers and scientists concentrate on finding type 1A supernovas because “Type 1A supernovas are superb candles, stellar explosions so bright that for a few days they can be brighter than entire galaxies. They can be seen across billions of light years” (1). Finding a 1A supernovas was no easy task until the Supernovas Cosmology Project developed a good method.
“Ground-based telescopes in Chile and elsewhere take pictures of small patches of sky, enough to include a thousand galaxies at a time. The same fields are recorded again three weeks later, both to take advantage of the dark of the moon, and, says Gerson Goldhaber, who developed the technique, “because we want to catch supernova before it reaches its maximum brightness.” Any new bright spot in the field is a supernova candidate” (1).
Astronomers compare the light from supernovas near and far to estimate the distance of each from earth. The farther away the supernova, the dimmer its light. The most distant ones discovered so far appear to have occurred more than seven billion years ago, about halfway back to the supposed moment of cosmic creation in the Big Bang. The nearer ones signal explosions some 5 billion years ago, a little before the sun and its planets were created. Next, the astronomers plot the supernova distances against the “redshift” of the objects’ light, a measure of how fast cosmic expansion was carrying the galaxies outward at the time of each explosion. This motion displaces the light of an object toward the long-wavelength, or red, end of the spectrum. (1)
The redshifts of the 40 supernovas the Supernova Cosmology Project studies, every single one showed that the universe has been expanding. (1) There was absoluteley no evidence to support that the Universe was not expanding by using the supernovas as measure sticks. “The most likely interpretation, the scientists concluded, is that the universe will expand foreever, galaxies continuing to drift apart and everything becoming darker and more tenuous” (5).
By observing and researching supernovas, one can decide that the Universe is expanding.
Ferris, Timothy. The Whole Shebang: A State-of-the-Universe Report. New York: Touchstone, 1997.
North, John. Astronomy and Cosmology. New York: W.W. Norton & Company, 1995.
Preuss, Paul. The Fate of the Cosmos. 20 November 1998
Royal Greenwich Observatory. 28 October 1998
Tyler, Pat. “Supernova.” High Energy Astrophysics Science Archive Research Center 25 February 2000
Wilford, John. “In the Light of Dying Stars, Scientists See Hints of Cosmic Immortality.” New York Times on the Web 21 April 1998