By Jimmy Westlake, professor of physical science, Alpine Campus
It’s been nearly a year since the planet Venus graced our evening sky. Venus spent last spring, summer, and fall, as our morning star, rising in the east an hour or two before the sun. Then, on January 11, Venus passed behind the sun as viewed from Earth in an event called superior conjunction and officially entered our evening sky.
Like a race car on the inside track, Venus moves around its orbit faster than Earth and gains a little on us each day. Consequently, Venus is moving out of the sun’s glare and a little higher into our evening sky every night. You can see her now, around 6:30 p.m., glimmering like a bright star, low in the colorful western sky.
Venus is the brightest object visible in our sky, except for the sun and moon. When at her brightest, Venus can cast faint shadows over the snow-covered ground. Venus is not self-luminous, but simply reflects sunlight towards us like a mirror. Her atmosphere, filled with yellowish-white clouds, reflects the sunlight very well. Combine that with her relatively close proximity to Earth and it’s easy to see why Venus shines so radiantly in our sky. She flip-flops between our morning sky and evening sky, spending about 10 months shining in each as she orbits the sun.
Through most of 2010, Venus will dominate our early evening sky as our evening star. Here are some upcoming cosmic events, starring Venus, that we can all look forward to:
Venus will pose beside the slender crescent moon once each month as the moon circles the Earth. Look for this striking pair after sunset on April and May 15, June and July 14, August 12, September 10, and October 9.
Venus will be joined by the planet Mercury on April 4 and will cluster together with the planets Mercury, Mars, and Saturn on August 12.
Watch Venus skim past the bright star Regulus on July 9 and the bright star Spica on August 31.
Venus will pass very close to three star clusters in the coming months, creating a breathtaking spectacle when viewed through binoculars or a low-power telescope. Venus will pass just below the Seven Sisters, or Pleiades, star cluster in Taurus on April 24, very close to the M35 star cluster in Gemini on May 21, and then very close to the Beehive star cluster in Cancer on June 16.
Venus is a beautiful sight on any clear night. She will be our constant evening companion from now until late October, looking over our shoulder during our evening walks. Welcome back, evening star!
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. He is an avid astronomer whose photographs and articles have been published all around the world. His “Celestial News” column appears weekly in the Steamboat Pilot newspaper. His “Cosmic Moment” radio spots can be heard on local radio station KFMU. Also, check out Jimmy’s Web site.