- Smith's Cloud
Smith's Cloud is a
high velocity cloud ofhydrogen gas located in the constellation Aquila atGalactic coordinates "l" = 39°, "b" = −13°. The cloud was discovered in 1963 byGail Bieger , "née " Smith, who was an astronomy student atLeiden University in the Netherlands.cite journal | url=http://adsabs.harvard.edu/abs/1963BAN....17..203S | title=Peculiar Feature at l = 40°.5, b = - 15°.0 | year=1963 | author=Smith, G.P. | journal=Bulletin of the Astronomical Institutes of the Netherlands | volume=17 | pages=203] Smith's cloud has a mass of at least one millionsolar mass es and measures convert|3000|parsec|ly|lk=on long by convert|1000|pc|ly|abbr=on wide in projection.cite journal | doi=10.1086/588838 | title=The Smith Cloud: A High-Velocity Cloud Colliding with the Milky Way | year=2008 | author=Lockman, Felix J. | journal=The Astrophysical Journal | volume=679 | pages=L21] The cloud is between convert|11100|parsec|ly|abbr=on and convert|13700|parsec|ly|abbr=on from Earth and has anangular diameter of 10 to 12 degrees, approximately as wide as the Orion constellation, or about 20 times the diameter of thefull moon , although the cloud is not visible to the naked eye.cite news | author=David Shiga | title=Giant gas cloud to crash into our galaxy | url=http://space.newscientist.com/article/dn13179-giant-gas-cloud-to-crash-into-our-galaxy.html | work=NewScientist.com | date=11 January 2008 | accessdate=2008-02-07]The cloud is apparently moving towards the disk of the
Milky Way at 73 ± 26kilometer s per second. Smith's Cloud is expected to merge with the Milky Way in 27 million years at a point in thePerseus arm . Astronomers believe it will strike the Milky Way disk at a 45° angle, and its impact may produce a burst ofstar formation or a supershell of neutral hydrogen.References
External links
* [http://www.sciencedaily.com/releases/2008/01/080112153747.htm Science Daily: Massive Gas Cloud Speeding Toward Collision With Milky Way]
* [http://news.bbc.co.uk/2/hi/science/nature/7184521.stm BBC: Huge gas cloud will hit Milky Way]
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