Finance          Automotive          Computers          Health          Shopping          Sports         News          Reference           Print Facts in English - BCUZ.COMlos hechos en Español

Milky Way



See also:Galaxy-Observation history
The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center.
The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center.

As Aristotle informs us in Meteorologica (DK 59 A80), the Greek philosophers Anaxagoras (ca. 500 BC–428 BC) and Democritus (450–370 BC) proposed that the Milky Way might consist of distant stars. The Persian astronomer Abū Rayhān al-Bīrūnī (973-1048 AD) further proposed the Milky Way galaxy to be a collection of countless nebulous stars.[41] Actual proof of this came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it was composed of a huge number of faint stars.[42] In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate "galaxies" themselves, similar to our own.[43]

The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the sky. He produced a diagram of the shape of the Galaxy with the Solar System close to the center.

Photograph of the "Great Andromeda Nebula" from 1899, later identified as the Andromeda Galaxy
Photograph of the "Great Andromeda Nebula" from 1899, later identified as the Andromeda Galaxy

In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant's earlier conjecture.[44]

In 1917, Heber Curtis had observed the nova S Andromedae within the "Great Andromeda Nebula" (Messier object M31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within our galaxy. As a result he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the "island universes" hypothesis, which held that the spiral nebulae were actually independent galaxies.[45] In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the universe. To support his claim that the Great Andromeda Nebula was an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.[46]

The matter was conclusively settled by Edwin Hubble in the early 1920s using a new telescope. He was able to resolve the outer parts of some spiral nebulae as collections of individual stars and identified some Cepheid variables, thus allowing him to estimate the distance to the nebulae: they were far too distant to be part of the Milky Way.[47] In 1936 Hubble produced a classification system for galaxies that is used to this day, the Hubble sequence.[48]


[

Further reading

  • Thorsten Dambeck in Sky and Telescope, "Gaia's Mission to the Milky Way", March 2008, p. 36 - 39

[

See also

[

References

  1. ^ The Milky Way is twice the size we thought it was. University of Sydney News. University of Sydney (2008-02-20). Retrieved on 2008-02-20.
  2. ^ a b [astro-ph/0212516] Gas Dynamics in the Milky Way: Second Pattern Speed and Large-Scale Morphology
  3. ^ a b Kogut, A.; Lineweaver, C.; Smoot, G. F.; Bennett, C. L.; Banday, A.; Boggess, N. W.; Cheng, E. S.; de Amici, G.; Fixsen, D. J.; Hinshaw, G.; Jackson, P. D.; Janssen, M.; Keegstra, P.; Loewenstein, K.; Lubin, P.; Mather, J. C.; Tenorio, L.; Weiss, R.; Wilkinson, D. T.; Wright, E. L. (1993). "Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps". Astrophysical Journal 419: 1. doi:10.1086/173453. 
  4. ^ Between 1×1010 and 8×1010
  5. ^ Freedman, Roger A.; Kaufmann, William J. (2007). Universe. WH Freeman & Co., p. 605. ISBN 0-7167-8584-6. 
  6. ^ "Galaxies — Milky Way Galaxy". Encyclopedia Britannica 19. (1998). Encyclopedia Britannica, Inc.. p. 618. 
  7. ^ Pasachoff, Jay M. (1994). Astronomy: From the Earth to the Universe. Harcourt School, p. 500. ISBN 0-03-001667-3. 
  8. ^ Christian, Eric. How large is the Milky Way?. Retrieved on 2007-11-28.
  9. ^ Sanders, Robert. "Milky Way galaxy is warped and vibrating like a drum", UCBerkeley News, January 9, 2006. Retrieved on 2006-05-24. 
  10. ^ Frommert, H.; Kronberg, C. (August 25, 2005). The Milky Way Galaxy. SEDS. Retrieved on 2007-05-09.
  11. ^ Milky Way fatter than first thought. The Sydney Morning Herald. Australian Associated Press (2008-02-20). Retrieved on 2008-04-24.
  12. ^ Connors, et al.. "N-body simulations of the Magellanic stream", Monthly Notices of the Royal Astronomical Society, January 26, 2007. Retrieved on 2007-01-26. 
  13. ^ Eduardo F. del Peloso a1a, Licio da Silva a1, Gustavo F. Porto de Mello and Lilia I. Arany-Prado (2005), "The age of the Galactic thin disk from Th/Eu nucleocosmochronology: extended sample" (Proceedings of the International Astronomical Union (2005), 1: 485–486 Cambridge University Press)
  14. ^ "Morphology of Our Galaxy's 'Twin'", Spitzer Space Telescope Newsroom, Spitzer Science Center. Retrieved on 2008-04-24. 
  15. ^ a b McKee, Maggie. "Bar at Milky Way's heart revealed", New Scientist, August 16, 2005. Retrieved on 2007-05-09. 
  16. ^ Ortwin, Gerhard (2002). "Mass distribution in our Galaxy". Space Science Reviews 100 (1/4): 129–138. doi:10.1023/A:1015818111633. 
  17. ^ Chen, W.; Gehrels, N.; Diehl, R.; Hartmann, D. (1996). "On the spiral arm interpretation of COMPTEL ^26^Al map features". Space Science Reviews 120: 315–316. 
  18. ^ Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics 49 (1): 3–18. doi:10.1007/s10511-006-0002-6. 
  19. ^ Vayntrub, Alina (2000). Mass of the Milky Way. The Physics Factbook. Retrieved on 2007-05-09.
  20. ^ a b Battaglia, G.; Helmi, A.; Morrison, H.; Harding, P.; Olszewski, E. W.; Mateo, M.; Freeman, K. C.; Norris, J.; Shectman, S. A. (2005). "The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way" (abstract). Monthly Notices of the Royal Astronomical Society 364: 433–442. 
  21. ^ Grant. J.; Lin, B.. "The Stars of the Milky Way", Fairfax Public Access Corporation. Retrieved on 2007-05-09. 
  22. ^ Blandford, R.D. (1999). "Origin and evolution of massive black holes in galactic nuclei". Galaxy Dynamics, proceedings of a conference held at Rutgers University, 8–12 Aug 1998,ASP Conference Series vol. 182. 
  23. ^ Staff (September 12, 2005). Introduction: Galactic Ring Survey. Boston University. Retrieved on 2007-05-10.
  24. ^ Imamura, Jim (August 10, 2006). Mass of the Milky Way Galaxy. University of Oregon. Retrieved on 2007-05-10.
  25. ^ a b Benjamin, R. A. (2008). "The Spiral Structure of the Galaxy: Something Old, Something New...". Beuther, H.; Linz, H.; Henning, T. (ed.) Massive Star Formation: Observations Confront Theory 387: 375, Astronomical Society of the Pacific Conference Series. 
    See also Bryner, Jeanna. "New Images: Milky Way Loses Two Arms", Space.com, 2008-06-03. Retrieved on 2008-06-04. 
  26. ^ Harris, William E. (February 2003). Catalog of Parameters for Milky Way Globular Clusters: The Database (text). SEDS. Retrieved on 2007-05-10.
  27. ^ Ibata, R.; Chapman, S.; Ferguson, A. M. N.; Lewis, G.; Irwin, M.; Tanvir, N. (2005). "On the accretion origin of a vast extended stellar disk around the Andromeda galaxy". Astrophysical Journal 634 (1): 287–313. doi:10.1086/491727. 
  28. ^ Outer Disk Ring?. SolStation. Retrieved on 2007-05-10.
  29. ^ Reid, Mark J. (1993). "The distance to the center of the Galaxy". Annual review of astronomy and astrophysics 31: 345–372. doi:10.1146/annurev.aa.31.090193.002021. 
  30. ^ Eisenhauer, F.; Schödel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003). "A Geometric Determination of the Distance to the Galactic Center". The Astrophysical Journal 597: L121–L124. doi:10.1086/380188. 
  31. ^ Horrobin, M.; Eisenhauer, F.; Tecza, M.; Thatte, N.; Genzel, R.; Abuter, R.; Iserlohe, C.; Schreiber, J.; Schegerer, A.; Lutz, D.; Ott, T.; Schödel, R. (2004). "First results from SPIFFI. I: The Galactic Center" (PDF). Astronomische Nachrichten 325: 120–123. doi:10.1002/asna.200310181. 
  32. ^ Eisenhauer, F. et al. (2005). "SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month". The Astrophysical Journal 628 (1): 246–259. doi:10.1086/430667. 
  33. ^ English, Jayanne. "Exposing the Stuff Between the Stars", Hubble News Desk, 1991-07-24. Retrieved on 2007-05-10. 
  34. ^ Gillman, M. and Erenler, H. (2008). "The galactic cycle of extinction". International Journal of Astrobiology. doi:10.1017/S1473550408004047. 
  35. ^ Leong, Stacy (2002). Period of the Sun's Orbit around the Galaxy (Cosmic Year). The Physics Factbook. Retrieved on 2007-05-10.
  36. ^ Garlick, Mark Antony (2002). The Story of the Solar System. Cambridge University, 46. ISBN 0521803365. 
  37. ^ University of California, Berkeley (2006-01-09). "Milky Way galaxy is warped and vibrating like a drum". Press release. Retrieved on 2007-10-18.
  38. ^ Wong, Janet. "Astrophysicist maps out our own galaxy's end", University of Toronto, April 14, 2000. Retrieved on 2007-01-11. 
  39. ^ Online Etymology Dictionary. Retrieved on 2007-01-03.
  40. ^ Harutyunyan, Hayk (2003-08-29). "The Armenian name of the Milky Way". ArAS News 6. Armenian Astronomical Society (ArAS). 
  41. ^ O'Connor, John J. & Robertson, Edmund F., “Abu Rayhan Muhammad ibn Ahmad al-Biruni”, MacTutor History of Mathematics archive 
  42. ^ J. J. O'Connor, E. F. Robertson (November 2002). Galileo Galilei. University of St Andrews. Retrieved on 2007-01-08.
  43. ^ Evans, J. C. (November 24, 1998). Our Galaxy. George Mason University. Retrieved on 2007-01-04.
  44. ^ Abbey, Lenny. The Earl of Rosse and the Leviathan of Parsontown. The Compleat Amateur Astronomer. Retrieved on 2007-01-04.
  45. ^ Heber D. Curtis (1988). "Novae in Spiral Nebulae and the Island Universe Theory". Publications of the Astronomical Society of the Pacific 100: 6. 
  46. ^ Weaver, Harold F.. Robert Julius Trumpler. National Academy of Sciences. Retrieved on 2007-01-05.
  47. ^ E. P. Hubble (1929). "A spiral nebula as a stellar system, Messier 31". Astrophysical JournalEngl 69: 103–158. doi:10.1086/143167. 
  48. ^ Sandage, Allan (1989). "Edwin Hubble, 1889–1953". The Journal of the Royal Astronomical Society of Canada 83 (6). 

[

External links

Wikimedia Commons has media related to:
v • d • e
The Milky Way
Location
The Milky Way Galaxy
Galactic core
Spiral arms
Satellite galaxies
Other
v • d • e
Earth's location in space
Each arrow should be read as "within" or "part of".




BCUZ.com FACTS Encyclopedia content is licensed under the GFDL as approved by Wikipedia.
For more information review our copyright contact and privacy policy.
© 1996 - BCUZ.COM - We have all the FACTS you need about Small Business Financing, Behavior Disorder, Having Too Many Bills, Needing Cash Fast, Structured Settlements, Frequent Flier Programs, Top Steak Houses, The Mayan Indians, Norfolk and Suffolk England, Growing Longer Hair and a full reference English Encyclopedia and Spanish Encyclopedia.Privacy Policy