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Earthsky Tonight—May 8: Jupiter and moon close together before dawn
Posted By Gary Wamsley On May 7, 2010 @ 10:59 pm In Earth & Sky | Comments Disabled
Courtesy of EarthSky
A Clear Voice for Science
 Tomorrow, on Sunday morning, May 9, the dazzling planet Jupiter sits beneath the waning crescent moon  at dawn. Both the moon and Jupiter light up the constellation Pisces the Fishes.
One day later, on Monday , the lunar crescent and Jupiter line up side by side, for another spectacular display at morning dawn.
Jupiter has more known moons than any other solar system planet. At the last count, there are 63 moons, though only four of them are of significant size (like Earth’s moon: 2,160 miles in diameter). Jupiter’s four major moons are called the Galilean moons, because Galileo first observed these moons in the early 1600s. The largest non-Galilean moon is potato-shaped Amalthea. Its length is only about 160 miles.
In the 1670s, the Danish astronomer Ole Romer found that the eclipses of Jupiter’s moons happened earlier than expected when Jupiter was closer to Earth, yet later than expected when Jupiter was farther away. Ole Romer correctly surmised that this must be due to the finite speed of light. In Ole Romer’s day, many people thought the speed of light was “instantaneous.” Light does travel very fast, but not infinitely fast. The speed of light is 186,000 miles per second.
When Jupiter comes closest to Earth, this planet lies about 33 light-minutes distant. At its farthest, Jupiter resides some 54 light-minutes away. At present, Jupiter looms about 45 light-minutes from Earth.
Written by Bruce McClure
StarDate Online 
Sky and Telescope 
National Geographic 
Space Com 
Amazing Space 
Scope City 
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URL to article: http://www.berthoudrecorder.com/2010/05/07/earthsky-tonight%e2%80%94may-8-jupiter-and-moon-close-together-before-dawn/
URLs in this post:
 www.EarthSky.org: http://www.EarthSky.org
 Image: http://www.berthoudrecorder.com/wp-content/uploads/2010/05/phase-08.gif
 Image: http://www.berthoudrecorder.com/wp-content/uploads/2010/05/10may08_430.jpg
 waning crescent moon: http://earthsky.org/tonightpost/moon-phases/waning-crescent
 Monday: http://earthsky.org/es-tonight/moon-moving-away-from-jupiter
 Astronomy Picture of the Day from NASA/JPL: http://antwrp.gsfc.nasa.gov/apod/
 CHANDRA Photo Album: http://chandra.harvard.edu/photo/
 U.S. Naval Observator Astronomical Information cente: http://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/astronomical-information-center
 StarDate Online: http://stardate.org/
 Sky and Telescope: http://www.skyandtelescope.com/observing/ataglance/
 National Geographic: http://news.nationalgeographic.com/news/
 Space Com: http://www.space.com/nightsky/
 Amazing Space: http://amazing-space.stsci.edu/tonights_sky/
 The York County Astronomical Society: http://www.ycas.org/tonights_sky.htm
 Scope City: http://www.scopecity.net/
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