Venus -- The Evening Planet.
Police stations around the world need to be on the alert: There will be a jump in UFO reports from now through the end of July, 2015. But that "bright light" in the west just after sunset isn't a UFO. It's a planet -- our closest planetary neighbor, Venus. It will be routinely mistaken for a UFO or helicopter or something equally sinister. Once you learn the details about Venus's march across our sky, you can enjoy viewing Venus and some of the more interesting stops during its tour.There are several reasons folks get agitated and suspicious about Venus in the night sky. First, it's bright -- really, really bright. Only our Moon is brighter in the night sky. Other planets like Mars, Mercury, Jupiter and Saturn appear as "bright stars" in the night sky. But, Venus is usually 10 times brighter than the brightest star in the night sky -- often more than 20 times brighter. So it looks far too bright to be a star. Anyone can see that it's obviously not part of a traditional constellation. It looks "wrong" in the sky.
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| Venus and dimmer Mercury set as Mars (upper left) waits. |
The second suspicious behavior of Venus is hanging around the horizon. It looks like it's up to no good. Venus (like Mercury) goes around the Sun in an orbit inside of Earth's. That means we never see Venus at midnight because it's always in the same part of the sky as the Sun. So when Venus swings between us and the Sun or swings on the far side of the Sun, we don't see it in the morning or evening sky. The bright glare of the Sun hides it. During the rest of its orbit, we see Venus in the pre-dawn or post-sunset sky, but never too far from the Sun.
You can actually see Venus in the daylight sky on a clear day if you know where to look. But against a bright blue sky it doesn't stand out. It doesn't grab your attention. Then, when the evening sky starts to darken, Venus seems to jump literally "out of the blue" as a blazing object in the west or east. (We tend to notice Venus in the west because we're more active in the evening than in the early morning.) Venus stands out the most when the sky is dark and by that time, the planet is often close to the horizon so it looks like it's hovering.
The final odd behavior of Venus is the appearance of flashing colors, especially close to the horizon. This is a combination of the brightness of Venus and the density of our atmosphere. The same air that causes the blue sky, the red and orange sunsets, and twinkling stars is behind Venus's curious lighting. As light passes through a lot of turbulent air, it gets separated (as with a prism) and twisted. High in the sky, Venus will be a bright, steady white because there isn't much air to twist the light. But close to the horizon the light travels through more of our air and you might see momentary flashes of red or orange or green or blue. Venus is still white, but that white light has been distorted before it gets to your eye.
When you combine these factors -- distinctly bright, hovering on the horizon, flashing colored lights -- it's not surprising that Venus motivates people to call in a report. It happens whenever Venus starts to make its appearance in the evening skies.
You can still enjoy Venus even though it isn't a UFO. You can use a telescope or binoculars if you want. But you don't really need anything more than your eyes to appreciate it. A nice telescope can show the phases of Venus -- much like the phases of our Moon. Early in the year, Venus will look like a bright white ball in a telescope. Its white clouds cover the planet. We never see any of the planet's surface like we can for the Moon and Mars. Eventually, that white ball will change into a half-Venus and then a crescent-Venus by the end of July. But we're always seeing those plain, featureless clouds.
In January, 2015, Venus is passing behind the Sun (as we see it) and it will continue to lap us -- much like a race car uses the inner path to pass a car on an outer path. It will start the year 150 million miles away from us, and end July "only" about 30 million miles away. By August, Venus will appear so close to the Sun that it will set just 30 minutes after sunset -- not enough time for the sky to darken.
As it passes through the sky Venus will appear to be near different stars, planets, and star clusters as well as the Moon. When the Moon or a planet gets close to something else in the sky, astronomers call that a "conjunction". You can enjoy most of these conjunctions with just your own eyes or binoculars. Below is a list of some of the best conjunctions for Venus's 2015 visit to the night sky. The ones marked "(T)" will need a telescope. Venus traipses slowly through the constellations, so you can enjoy most of the conjunctions a day before and a day after the listed date. The Moon moves faster through the constellations so you'll need to view any of the lunar conjunctions on the date listed. Some of the conjunctions include three objects (triplet) or four objects (quartet).
So enjoy the shining light of Venus as it wanders around our evenings for most of 2015.
STOPS ON THE VENUS 2015 TOUR
January 21: Wide triplet with Moon, Mercury
February 1: Close to Neptune (T)
February 20: Triplet with Moon, Mars
February 21: Close to Mars
March 4: Close to Uranus (T)
March 22: Close to Moon
April 10: Close to Pleiades star cluster
April 21: Wide triplet with Moon, star Aldebaran
April 30: Close to star Alnath
May 21: Wide quartet with Moon, stars Castor, Pollux
May 29: 3° From star Pollux
June 2: Wide triplet with stars Castor, Pollux
June 12: Wide triplet with Jupiter, star Regulus
June 13: Close to Beehive star cluster
June 19: Wide triplet with Moon, Jupiter
June 20: Wide triplet with Moon, Jupiter
June 30: Close to Jupiter
July 18: Wide quartet with Moon, star Regulus, Jupiter
July 14: Close to star Regulus
