Minnesota Starwatch

University of Minnesota

Department of Astronomy

Minnesota Starwatch for June 2005
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Starwatch Newsletter

Minnesota Starwatch is a newsletter describing the night sky in the Midwest.

It is updated monthly, and is produced by the
Department of Astronomy, University of Minnesota
116 Church Street SE, Minneapolis, MN 55455

Minnesota Starwatch for June 2005

Hello, this is Minnesota Starwatch for June 2005. The best show in the sky this month should be the collection of bright planets in the western sky as the sky darkens after sunset. Venus, Mercury and Saturn will be close together all month in the constellation Gemini; during the last week of June, they will be within a couple of degrees of each other. Venus is, as usual, the brightest of the three, followed by Saturn, then Mercury. Mercury is the smallest of the major planets after Pluto, being only a little larger than the earth~Rs moon; it also has a dull, rocky surface with no atmosphere. Venus and Saturn, by contrast, have dense atmospheres with high clouds that reflect a large fraction of the sunlight that strikes them. This is why Mercury is fainter than either of the other two, despite the fact that right now Mercury is closer to Earth than the others. All three are, in fact, currently on the far side of the sun, near their maximum distances from the earth. Early in June, Saturn lies to the south of Venus and higher in the sky, but by July 1, Venus and Mercury will be more southerly and higher in the sky during dusk.

As the sky darkens you should be able to notice Jupiter shining brightly in the south about 30 degrees above the horizon. On the night of June 15th -16th the moon will pass very close in our sky to Jupiter giving us a remarkable pair to view. Jupiter, of course, is the giant among planets in our solar system. In the past decade, however, astronomers have discovered dozens of planets around other stars much more massive than our Jupiter. About the time Jupiter sets in the western sky, an hour or two after midnight, Mars will begin its ascent in the eastern sky. Mars is always relatively easy to spot due to its reddish hue. Remember that planets, unlike stars, usually do not twinkle. That difference comes from the fact that the planets of the solar system are so very much closer to us than any star except the Sun. The planets show us clearly visible disks, even in small telescopes. On the other hand, at their great distances, the stars are little more than points of lights as seen from earth. Turbulence in our atmosphere causes their images to dance around and flicker; what we call twinkling.

For fun Astronomy Outreach programs check out our Public Outreach link, or if you're interested in how you can help build the new Minnesota Planetarium, please call 612-630-6151 or visit http://www.mplanetarium.org. Como Planetarium is offering fun family shows about astronomy on a limited basis; please call 651-293-5398 for more info! This has been a Minnesota Starwatch produced by the University of Minnesota Astronomy Department.