Jimmy Westlake: See Venus at its best
October 28, 2013
Steamboat Springs — The dazzling planet Venus has been our constant evening companion all summer and fall. There it is, every night, right after sunset, glowing in the southwestern sky through the pastel colors of dusk.
As the first "star" to pop out after sundown, Venus is popularly known as the Evening Star, but, of course, it isn't a star at all. Venus is the second planet from the sun in our solar system and shines by reflected sunlight. Its atmosphere is filled with yellowish-white clouds of sulfuric acid that reflect the sunlight very well, thus making it the brightest object in our earthly skies after the sun and moon.
Venus is just slightly smaller than Earth but orbits much closer to the sun, completing an orbit in 225 days, compared to 365 days for Earth. Its proximity to the sun and its rich atmosphere of carbon dioxide creates a sizzling surface temperature of 900 F under a pressure of 90 Earth atmospheres. Indeed, the surface of Venus is like a pressure cooker, with acid rain thrown in for good measure.
The Soviet robots that landed on the surface of Venus in the 1970s and 1980s were only able to radio data back to Earth for an hour or two before they succumbed to the extremely harsh conditions.
Venus will pose beside the slender crescent moon at dusk on Nov. 6 and again on Dec. 5. These conjunctions of Venus and the moon are always eye-catching. With a telescope, you can watch the phase of Venus change like a miniature moon from a quarter phase this month to a thin crescent by December.
Venus will reach its greatest elongation 47 degrees east of the setting sun on Nov. 1. On that evening, Venus will remain in the sky for about two and a half hours after the sun goes down. Then, Venus will start closing the gap between it and the sun, and Venus will dive in between the Earth and sun on Jan. 11, 2014. At that point, it leaves our evening sky to become our Morning Star for much of 2014.
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When Venus leaves our evening sky at the end of this year, our winter nights will seem very empty, indeed. Fortunately, the planet Jupiter will slip into our evening sky to partially fill the void.
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 Jimmy's astrophotography website at http://www.jwestlake.com.