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Vega Credit: D. Moffatt (DOA …
Title Vega Credit: D. Moffatt (DOA [ http://www.dao.nrc.ca/ ]), ScienceWeb [ http://scienceweb.dao.nrc.ca/ ], Starry Messenger Communications
Explanation Vega is a bright blue star 25 light years away. Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=06/15/1996&field=ScriptAirDate&html=Test+Request+Date ] is the brightest star in the Summer Triangle [ http://eagle.online.discovery.com/DCO/doc/1012/world/starshack/starshack080796/starshack.html ], a group of stars easily visible summer evenings in the northern hemisphere. The name Vega [ http://www.astro.wisc.edu/~dolan/constellations/hr/7001.html ] derives from Arabic origins, and means "stone eagle." 4,000 years ago, however, Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=05/20/1995&field=ScriptAirDate&html=Test+Request+Date ] was known by some as "Ma'at" - one example of ancient human astronomical knowledge and language. 14,000 years ago, Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=07/10/1994&field=ScriptAirDate&html=Test+Request+Date ], not Polaris [ http://www.arcorp.com/polaris.html ], was the north star [ http://antwrp.gsfc.nasa.gov/apod/ap961201.html ]. Vega [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ%2E%2E%2E450%2E%2E364G&db_key=AST&nosetcookie=1 ] is the fifth brightest star in the night sky, and has a diameter almost three times that of our Sun. Life [ http://www.seti-inst.edu/phoenix/contact.html ] bearing planets, rich in liquid water, could possibly exist around Vega [ http://lsnt7.lightspeed.net/~astronomy/lifezones/lifezones.html ]. The above picture [ http://www.jpl.nasa.gov/comet/moffatt1.html ], taken in January, finds Vega, the Summer Triangle [ http://antwrp.gsfc.nasa.gov/apod/ap961212.html ], and Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970610.html ] high above Victoria [ http://www.city.victoria.bc.ca/ ], British Columbia [ http://www.gov.bc.ca/ ], Canada.
Polaris: The North Star
Title Polaris: The North Star
Explanation Polaris is quite an unusual star. First, Polaris [ http://einstein.stcloudstate.edu/Dome/constellns/polaris.html ] is the nearest bright star to the north spin axis [ http://antwrp.gsfc.nasa.gov/apod/ap980912.html ] of the Earth. Therefore, as the Earth turns, stars appear to rotate around Polaris [ http://www.physics.pacificu.edu/sci170/movies/nightly.html ], making it the North Star [ http://www.physics.csbsju.edu/astro/CS/CS.03.html ]. Since no bright star is near the south spin axis of the Earth, there is currently no South Star [ http://antwrp.gsfc.nasa.gov/apod/ap960503.html ]. Thousands of years ago, Earth's spin axis pointed in a slightly different direction [ http://www.fourmilab.ch/yoursky/help/precession.html ], and Vega [ http://antwrp.gsfc.nasa.gov/apod/ap980823.html ] was the North Star. Although Polaris [ http://www.seds.org/~spider/spider/Misc/alphaUMi.html ] is not the brightest star [ http://www.astro.wisc.edu/~dolan/constellations/extra/brightest.html ] on the sky, it is easily located because it is nearly aligned with two stars in the cup of the Big Dipper [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Ursa_Major.html ], and is the last star in the handle of the Little Dipper [ http://www.astro.wisc.edu/~dolan/constellations/constellations/Ursa_Minor.html ]. In the above picture, Polaris [ http://www.astro.wisc.edu/~dolan/constellations/hr/0424.html ] is the brightest star on the right, above the fleeting streak of a Perseid meteor [ http://antwrp.gsfc.nasa.gov/apod/ap960809.html ]. The surface of Polaris slowly pulsates [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1994PASP..106..964B ], causing the star to change its brightness by a few percent over the course of a few days. This rare Cepheid variability [ http://antwrp.gsfc.nasa.gov/apod/ap960110.html ] of Polaris is, oddly enough, itself changing [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998AJ....116..936K ].
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