Astronomers Essay Research Paper Part OneBrief Descriptions — страница 2

and then using a large optical telescope to find a visual starlike source at the point where the strong radio waves are being emitted. Sandage and Matthews identified the first of many such objects Sandage later discovered that some of the remote, starlike objects with similar characteristics are not radio sources. He also found that the light from a number of the sources varies rapidly and irregularly in intensity. Part Two Cerro Tololo Interamerican Observatory Cerro Tololo is a mountatin peak in the nothern range of the Andes in South America. At the summit, 7,200 ft. above sea level, the US has built on of the world’s foremost astronomical observatories. This is called the Cerro Tololo Interamerican Observatory or CTIO. It was founded in 1965 in Chile as the southern branch

of the Kitt Peak National Observatory. It is located about 285 miles north of Santiago and 50 miles inland from the coastal city of La Serena. The European Southern Observatory and the Carnegie Institution of Washington also operate major astronomical observatories nearby. It’s coordinates are : W 70d48m52.7s S 30d09m55.5s CTIO’s facilities are available for use for approved projects by all qualified astronomers in the western hemisphere. CTIO is operated by the Association of Universities for Research in Astronomy Inc. (AURA), under a cooperative agreement with the National Science Foundation as part of the National Optical Astronomy Observatories, which also operates Kitt Peak National Observatory in Tucson Arizona and is the operating agency for the US portion of the

International Gemini Project. The CTIO houses several telescopes and auxiliary instruments, the most significant of which is a reflecting telescope with a 4-metre mirror. On site are six optical telescopes, and one radio telescope: 4.0 Meter Blanco Telescope. 1.5 Meter Ritchey-Chretien Telescope. Yale 1.0 Meter Ritchey-Chretien Telescope f/10 (19.5 arcsec/mm). 0.9 Meter Telescope f/13.5 (16.5 arcsec/mm). Curtis/Schmidt Telescope (0.6/0.9 Meter) f/3.5 (96.6 arcsec/mm). Lowell (0.6m) Telescope f/13.5, f/75 (25.0, 4.5 arcsec/mm) 1.2m Radio Telescope (SCMT, Universidad de Chile). The observatory is best noted for its research on the central region of the Milky Way Galaxy, the Magellanic Clouds, and high-energy cosmic radio and X-ray sources. Part Three How Galaxies Evolve : The study

of the origin and evolution of galaxies has only just begun. In the past there has not been much data to work with, and many models of galaxy formation and evolution have been constructed on the basis of presumptions about conditions in the early universe, which are in turn based on models of the expansion of the Cosmos after the “big bang”–the explosion from which the Universe is thought to have originated. Prevailing theory has it that at crucial points in time there condensed from the expanding matter smaller clouds (protogalaxies) that could collapse under their own gravitational field and eventually form galaxies. At the time when the mass of such a stable perturbation in the cloud was approximately 10 solar masses, the galaxies formed. It is still not known whether

the clusters of galaxies emerged first or whether they resulted as accumulations of already formed galaxies. Following the separation of mass into individual galaxies, the next step probably depe! nded on the characteristics of the particular clump of matter involved, especially on its mass and angular momentum. The latter quantity was the most likely determinant of the form of the galaxy that eventually evolved. It is thought that a protogalaxy with a large amount of angular momentum tended to form a flat, rapidly rotating system (a spiral galaxy), whereas one with very little angular momentum developed into a more nearly spherical system (an elliptical galaxy.) Calculations show that a galaxy very gradually becomes dimmer and redder as time progresses and its constituent stars

evolve. There is some evidence from very distant galaxies–those whose light was emitted billions of years ago when they were younger–that the effects of this kind of slow evolution can actually be seen. Part Four Three Great Scientists Of The Past (In My Opinion) Based on my readings I believe that the following scientist have all made valuable contributions to astronomy : Copernicus Galileo Kepler Here are some brief descriptions of their contributon to the understanding of astronomy: Copernicus (1473-1543) : Nicolas Copernicus is often considered the founder of modern astronomy. His study led to his theory that the Earth rotates on its axis and that the Earth and the planets revolve around the sun. The Copernican theory was contrary to the Ptolemaic theory then generally