Celestial News: Jupiter joins Venus in May skies
Starting this month, there will be two evening stars lighting up our night sky.
Lingering in the west after the sun goes down is dazzling Venus, the cloud-shrouded second planet from the sun. Venus will be with us throughout spring and summer, outshining every other object in the sky, save for the sun and moon. Watch as Venus rapidly migrates across the constellations of Taurus and Gemini during May, ending the month near the bright twin stars of Castor and Pollux.
New on the evening scene this month is Jupiter, the fifth and largest planet in our solar system. Earth has been chasing Jupiter around the sun since last April and will finally catch up with and pass Jupiter when it reaches opposition to the sun on May 8.
Jupiter then will be at its closest point to Earth and brightest in our sky for 2018, some 4.40 astronomical units or 409-million miles from Earth. The giant planet will rise in the east just as the sun sets in the west and will gleam brilliantly in our midnight sky with the stars of the constellation of Libra, the Scales, behind it. Jupiter will be hanging out all spring and summer close to Libra’s alpha star, Zubenelgenubi. The two will appear closest together on June 3 and again on August 16.
To catch both evening stars in the sky at the same time, go outside around 9:30 p.m before Venus sets. Spot Venus in the northwestern sky and then turn around to see Jupiter in the southeastern sky. You’ll be able to tell that Venus shines about four times brighter than the king of the planets.
Any small telescope will reveal Jupiter to be a glowing yellowish ball with two dark cloud stripes straddling its equator. It requires a larger backyard telescope to glimpse the famous Great Red Spot. Recent studies have shown that the Great Red Spot is shrinking. Once wider than two Earths, Jupiter’s most famous storm now is only a bit wider than one Earth. Will it continue to shrink and eventually disappear? Scientists aren’t sure what’s going to happen next with the Great Red Spot.
A small telescope also will reveal Jupiter’s four planet-sized moons – Io, Europa, Ganymede and Callisto — discovered in 1610 by Italian astronomer Galileo Galilei. Io is the most volcanically active world in our solar system. Europa has an ocean that contains more water than all of Earth’s oceans combined. Ganymede is the largest of all the moons in our solar system, even surpassing planet Mercury in size. Callisto ranks as the solar system’s third largest moon. Watch from night to night as these Galilean moons constantly change their positions around Jupiter.
Our own moon will pair up with Jupiter in the sky about once a month for the remainder of this year. Watch for them posing together on the following nights May 27, June 23, July 20, Aug. 17, Sept. 13 and Oct. 11.
NASA’s Juno spacecraft has been orbiting Jupiter since July 4, 2016 and is trying to determine how Jupiter formed and how it has changed over time. If you want to see some of Juno’s spectacular images of Jupiter’s swirling storms, visit NASA’s Juno website at jpl.nasa.gov/missions/juno.
Jimmy Westlake retired from full-time teaching at Colorado Mountain College Alpine Campus in Steamboat Springs in 2017, after 19 years as professor of physical sciences. His “Celestial News” column appears monthly in Steamboat Pilot & Today. Check out Westlake’s astrophotography website at jwestlake.com.
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