Venus and Jupiter put on a show this week
They're by far the brightest starlike objects in the night sky. You don't need a telescope to enjoy them, although that'll add to the spectacle.
Venus and Jupiter reach their closest hugging this week. They won't be touching each other, but they'll be separated by only 3 degrees. That's the width of three of your fingers held together at arm's length. Venus to the right of Jupiter is definitely the brighter of the planet duo.
Even though 88,000-mile-wide Jupiter dwarfs Venus' 7,600 mile girth, Venus is much brighter because it's a lot closer and very reflective. Venus is about 75 million miles away this week and is shrouded by a highly reflective but poisonous clouds of carbon dioxide laced with carbon monoxide and acid rain.
That thick atmosphere of carbon dioxide traps terrestrial heat under the clouds to the point where surface temperatures can exceed 800 degree on the planet named after the Roman goddess of love.
All you see through a telescope is an ovalish bright white light. The planets Venus and Mercury go through a shape change phase cycle just like our moon, only on much longer cycles. Sometimes they even show up crescent shaped. That's because planets do not produce light on their own but rather just reflect the sun's light.
Jupiter is more than five times fainter than Venus but is still very bright in night sky. Even though it's fainter Jupiter overwhelms Venus in size. If the gaseous giant Jupiter were a hollow sphere You could fill it up with more than 1,300 Venuses.
Jupiter's not as bright as Venus mainly because a lot farther away at more than 520 million miles. It was actually closer to Earth last autumn, about 475 million miles, which for Jupiter is considered close.
Even though it's little more distant now Jupiter's still a great telescope target. Depending on where they are in their orbits around Jupiter you can see up to four of its larger moons that resemble tiny little stars on either side of the great planet.
If Earth's atmosphere is still enough and transparent enough on a given night you might even see darker diagonal lines and bands across the face of Jupiter that are clouds of ammonia, methane, water vapor and other gases.
Conjunctions between planets and between planets and the moon are common. Obviously the planets are physically nowhere near each other when in conjunction, but nearly in the same line of sight from Earth.
All the major planets in our solar system orbit the sun in nearly the same flat plane. The farther they are from the sun the larger their orbital circles and slower they progress around our home star. So it's really just a matter of time for the planets like Jupiter and Venus to be aligned in such a way to make a great show.
What makes this show so special is that both planets are fairly high in the sky in the early evening. We won't have a conjunction as good as the present Venus and Jupiter show until the autumn of 2015.
So enjoy the celestial happening. After this week Jupiter and Venus will begin to part company so every evening that it's clear enough, have a look. Make sure you catch show early in the evening because the dynamic duo of the west slips below the horizon by around 10 p.m.
Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, "Washington Starwatch," available at bookstores. Check his website, www.lynchandthestars.com.
The Everett Astronomical Society: www.everettastro.org/.
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