This week, you have an opportunity to see five of Earth's closest neighboring planets, from Mercury to Saturn, in the evening sky.
Venus
Without a doubt, the easiest planet to see is Venus. Since right around Christmas, Venus has been dominating the lower western sky. In fact, it pops out well before the end of evening twilight. You can't miss it. It's by far the brightest star-like object in the heavens, less than 90 million miles away.
It's also the closest planet to our Earth right now. It's so bright because of its thick and very reflective cloud cover that bounces a lot of sunlight in our direction. The clouds surrounding Venus are made up of a corrosive sulfuric acid. You wouldn't want to float around in those clouds for too long.
As bright as Venus is, it's really boring through binoculars or a telescope. It's just a super bright light. The only really interesting thing you'll observe over the course of several months is that Venus goes through phases just like our moon. This happens because the angle between Earth, Venus and the sun changes as both planets orbit our home star. Right now, Venus resembles a football shaped gibbous moon.
Mercury
The next planet to look for is Mercury, the closest planet to the sun. Because of that proximity, Mercury is always found very close to the sun in our sky as well. About a half hour after sunset, start looking for Mercury fairly close to the western horizon. You can use Venus to find it. Mercury will be next brightest star-like object you'll see to the lower right of Venus. Hold out your fist at arm's length. Mercury will be just over two of your fist-widths at arm's length to the lower right of Venus. You'll probably see it easily with the naked eye, although binoculars will help. Mercury doesn't have a cloud cover, but since it's so small and so close to the horizon, it will just resemble a fuzzy little star.
Even closer to the horizon it's possible to find Mars, about a half hour after sunset. This will be your biggest observing challenge by far. Mars will be just above the horizon, about a fist-width to the lower right of Mercury. With a pair of binoculars, scan just above the horizon in that general area and see if you can spot a very fuzzy reddish star. Mars is well over 200 million miles from Earth right now.
Jupiter
Jupiter is one of the best planets to see in the evening sky right now. It's the second brightest star-like object in the evening sky, starting out high in the southwest. The largest planet in our solar system, basically a giant ball of hydrogen and helium gas, is now just under 500 million miles away. Jupiter, at 88,000 miles in diameter, is so large that if it were hollow, you could fill it up with more than 1,100 Earths.
Through even a small telescope, you can spot at least some of the brighter cloudbands made of sulfur, ammonia, methane and other gases that encircle the gargantuan planet. You can also easily spot up to four of Jupiter's largest moons that resemble tiny little stars. They circle the big guy of the solar system in periods of two to seventeen days. Every night, they're in different positions on either side of the planet. Sometimes you can't see them all because one or more may be behind the planet or camouflaged directly in front of it.
Saturn
Around 10:30 to 11 p.m., look in the low southeast sky for another wonderful planet that's on the rise. It's Saturn, the ringed wonder of our solar system. Saturn is the brightest star-like object in that part of the sky. Most people, including yours truly, think it's the best thing you can see through a telescope, even a small one. You can clearly see the ring system made up of billions and billions of ice covered rocks that range in size from pebbles to possibly as big as school buses. Through your telescope, you may even see some of Saturn's many moons. To get the best view of Saturn through your scope, it's best to wait until after midnight if you can. By then, the planet will be higher above the southeast horizon and you won't have as much of Earth's blurring atmosphere in the way.
Saturn is just about at its closest distance to the Earth right now at a little over 825 million miles away, and will be available in our night sky all summer long. I'll have a lot more on Saturn in the coming weeks.
Pluto
I want to bring up Pluto as long as I'm talking planets this week. Pluto is no longer considered a planet by astronomers, but rather a minor or dwarf planet. This downgrading of Pluto took place in 2006. Don't feel too sorry for Pluto though because it will be getting a lot of attention this summer when NASA'S New Horizon probe passes within 120,000 miles of the former planet July 14. New Horizons is already sending back the first color images of Pluto ever. You can see them and keep up with the progress of the mission at www.nasa.gov/mission_pages/newhorizons/main/index.html
(Lynch is an amateur astronomer and is author of the book, "Stars, a Month by Month Tour of the Constellations." Contact him at mikewlynch@comcast.net.)
