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Quasars and Active Galaxies

al quasar discovery was dependent on a combination of spectroscopy and radio astronomy. A brief description of spectroscopy is when a ray of light is split into the colors of a rainbow through a spectrum, energy is emitted or absorbed by the colors. Astronomers use the spectra of light to determine temperature, velocity, and more. The majority of astronomers believe that if the spectra of a point of light has a significant redshift, then the object is a good candidate for a quasar. A redshift symbolizes a motion-induced change in wavelength, indicating that an object is very far away, and rapidly moving away from the observer’s line of sight (Chaisson 71,93). If the object is extremely distant, and can be seen as a point of light, then it must emit an enormous amount of energy (Bartusiak 56; Disney 53). With the use of radio astronomy, it was determined that a star named 3C273, located in the Virgo constellation, was emitting radio waves. Normal stars, however, do not emit radio waves (Hawking). Because of this unusual phenomenon, the visible light spectrum of 3C273 was analyzed by Maarten Schmidt, an astronomer at the Mount Palomar Observatory in California. He was bewildered when he found a sixteen percent redshift “due to the expansion of the universe.” The redshift indicated an object approximately two billion light-years away. “Given the distance and the observed brightness of the object, Schmidt calculated that it had to be emitting several hundred times more light than any galaxy” (Disney 53,54). Through the use of spectroscopy, 3C273 was deemed a quasar rather than a star. The question of how a quasar could radiate so much energy, yet be relatively small was on the minds of astronomers and physicists. General relativists brought up the idea of gravitational collapse as a possible explanation. A catastrophic gravitational collapse of an object such as a star in a galaxy would caus...

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