Distance to the Nearest Galaxy

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Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Shu, Frank H. The Physical University: An Introduction to Astronomy. California: University Science Books, 1982: 291. "The modern value for this distance is 2 million light years away, which places it well outside the confines of the Milky Way." 2 million light years
(Andromeda)
World Book Encyclopedia. New York: World Book, 1998: 8-9. "People in the Northern Hemisphere can see the Andromeda Galaxy, which is about 2 million light years away." 2 million light years
(Andromeda)
Jastrow, Robert. Red Giants and White Dwarfs. New York: Norton, 1990: 236. "The nearest galaxy of comparable size to our own is the Great Nebula in Andromeda, located approximately 2 million light years away from us" 2 million light years
(Andromeda)
Robinson, Michael Rowan. Cosmology. New York: Clarendon, 1977: 3. "Two million light years away, it is almost the twin of our own Galaxy seen tilted to our line of sight" 2 million light years
(Andromeda)
Deakes, Kevin. The Andromeda Galaxy. The Andromeda Observatory. South Yorkshire, England. "The Andromeda Galaxy is generally regarded as the most distant object visible to the human eye at a distance of 2.2 million light years away" 2.2 million light years
(Andromeda)
Moche, Dinah L. Astronomy. New York: Wiley, 1996: 154. "The Large Magellanic Cloud and the Small Magellanic Cloud are held by a force of gravity at a distance of about 169,000 light years and 210,000 light years away, respectively." 169,000 light years
(Large Magellanic Cloud)
210,000 light years
(Small Magellanic Cloud)
Mitton, Jacqueline. Dictionary of Astronomy. New York: Penguin, 1991: 236. "The Large Magellanic Cloud is in the constellation Tucana and is about 169,000 light years away. The Small Magellanic Cloud in Dorado is about 210,000 light years away." 169,000 light years
(Large Magellanic Cloud)
210,000 light years
(Small Magellanic Cloud)

A galaxy is a system of stars, dust and gas held together by gravity. Galaxies are scattered throughout the universe. They range in diameter from a few thousand to half a million light years. A light year is the distance that light travels in a year -- about 5.88 trillion miles (9.46 trillion kilometers). Astronomers have examined and photographed millions of galaxies through telescopes. They estimated that there are about 100 billion galaxies in the universe.

Among the numerous numbers of galaxies in the universe, our very own solar system is located in the galaxy known as the Milky Way. The Andromeda Galaxy located at a distance of 2 million light years away is the nearest major galaxy and is of comparable size to our own galaxy. The Magellanic Clouds are irregular dwarf galaxies that are even nearer. The Small and Large Magellanic Clouds are located 165,000 light years and 195,000 light years away respectively. However, Andromeda is the nearest major galaxy and is the most distant celestial object still visible to the naked eye.

The Andromeda Galaxy is a spiral galaxy, shaped like a disk with a bright central region. It looks something like a pinwheel, with bright spiral arms that seem to emerge or coil out from the center. The Andromeda Galaxy, which was discovered in the 18th century, was said to be the twin of our very own Milky Way Galaxy due to its resemblance in size, shape, and number of stars. By virtue of its proximity the Andromeda Galaxy has drawn the attention of astronomers through the last 100 years causing great debates. Many astronomers had questioned if the galaxy was really in fact outside our own Milky Way. In 1923 Edwin Hubble had provided solid evidence that this spiral nebulae was in fact located well outside the confines of our galaxy. He was able to accomplish such a task by observing Cepheid variables -- stars that brighten and dim periodically. From apparent brightness and the period-luminosity relation, Hubble was able to show that Andromeda Galaxy lay outside the Milky Way.

Andromeda is our sister galaxy, the nearest spiral, similar in most attributes to our own Milky Way. Understanding Andromeda provides for understanding not only about the galaxy itself, but also about our own galaxy as well.

Sara Li -- 1999

Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Ribasi, Ignace, et al. First Determination of the Distance and Fundamental Properties of an Eclipsing Binary in The Andromeda Galaxy. arXiv.org, astro-ph/0511045 (1 November 2005). "We present the first detailed spectroscopic and photometric analysis of an eclipsing binary in the Andromeda Galaxy (M31) …. The result is d=772+/-44 kpc ((m-M)_0=24.44+/-0.12 mag) …." 2.52 ± 0.14 million light years
(Andromeda)
Ibata, Rodrigo, G. Gilmore, M.J. Irwin Sagittarius: The Nearest Dwarf Galaxy. Monthly Notices of the Royal Astronomical Society. Vol. 277 (1995): 781. arXiv.org astro-ph/9506071. "We have discovered a new Galactic satellite galaxy in the constellation of Sagittarius. The Sagittarius dwarf galaxy is the nearest galaxy known, subtends an angle of $> 10$ degrees on the sky, lies at a distance of $24 \kpc$ from the Sun, $\sim 16 \kpc$ from the centre of the Milky Way." 78,000 light years
(Sagittarius Dwarf Elliptical)
Closest Galaxy Discovered, Universe Today, 04 November 2003. "An international team of astronomers from France, Italy, the UK and Australia has found a previously unknown galaxy colliding with our own Milky Way. This newly-discovered galaxy takes the record for the nearest galaxy to the centre of the Milky Way. Called the Canis Major dwarf galaxy after the constellation in which it lies, it is about 25000 light years away from thesolar system and 42000 light years from the centre of the Milky Way. This i[s] closer than the Sagittarius dwarf galaxy, discovered in 1994, which is also colliding with the Milky Way" 25,000 light years
(Canis Major Dwarf)

Editor's Supplement -- 2006


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