Jimmy Westlake's Celestial News column appears monthly in the Steamboat Today.
Find more columns by Westlake here.
The five naked-eye planets — Mercury, Venus, Mars, Jupiter and Saturn — are among the brightest objects visible in our earthly sky. These wandering stars occasionally pass close to one another as they thread their way through the 12 constellations of the zodiac. During the second half of May, three of these planets — Venus, Jupiter and Mercury — will cluster in our evening sky and put on quite a show.
Venus, our lovely evening star, has been absent from our evening sky for many months, but it now is emerging from the solar glare and can be spotted very low in the western sky between 8:30 and 9 p.m. Venus will appear a little higher and farther from the sun each evening after sunset. Jupiter has been the brightest planet in our evening sky all winter and spring but its reign is coming to a close as it sinks lower into the colorful sunset glow with each passing evening. Thus, the stage is set for a spectacular meeting, or conjunction, of the two brightest planets as Venus rises out of the sunset glow and Jupiter sinks into it.
But wait; there’s more. Swift-moving Mercury, the innermost and smallest of the planets, also will emerge from the sun’s glare in the latter half of May and join the bright Venus-Jupiter pair. Scan the west-northwestern horizon each evening between 8:30 and 9 p.m. to watch as these three planets close in on one another. Binoculars will enhance the view but aren’t required.
The real excitement begins May 24, when Venus and Mercury pass only 1.4 degrees from each other. Then, on the evening of May 26, the trio of planets will form a tight equilateral triangle about 2 degrees on each side. You will be able to easily hide three planets behind your thumb held at arm’s length. Then, Mercury and Jupiter will appear only 2 degrees apart May 27, and Venus and Jupiter will be closest May 28, only 1 degree apart. When the two brightest planets appear that close together, it’s always a “Wow!” moment.
Of course, the planets aren’t really as close together as they seem. They just happen to lie along the same line of sight from Earth, so there is no danger of a collision.
While you are outside watching the conjunction of three planets in the western sky, turn around and spot bright, yellow Saturn rising in the southeastern sky.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out Westlake’s astrophotography website at www.jwestlake.com.