By Mike Lynch
Four of the five planets that we can see in the night sky are having quite a tango. Mars and Saturn are pairing off in the evening sky with Venus and Jupiter in a really tight celestial hug, just before morning twilight. You don’t want to miss either of these conjunctions that can both be easily seen with the naked eye.
Mars and Saturn won’t be as close as Venus and Mars, but it’s still worth your while to at least take a glance or to dig into it a little deeper with a small to moderate telescope. As darkness sets in, earlier now than it was at the start of summer, look for the two brightest star-like objects you can see close together in the low southwestern sky. The one on the lower right sporting a reddish tinge is Mars and the shiner on the upper left is Saturn. At the start of this week Mars and Saturn will be separated by just over five degrees, which is about the width of your hand held out at arm’s length. By the end of the week Mars and Saturn will be more vertically orientated and only three degrees apart, or about the length of six full moons lined up end to end. For extra credit, see if you can spot a fainter star about halfway between the two planets after darkness really sets in. That’s Zubenelgenubi, about 446 trillion miles away in the faint constellation Libra. There’s a mouthful for a stellar name.
Mars is right around 121 million miles away, and an instantaneous trip to Saturn tonight would require you to put almost 950 million miles on your spaceship. Even though Mars is much closer to Earth, Saturn is by far a better target through your telescope, even if you have a smaller scope. That’s because Mars is a much smaller planet than Saturn, and in fact has only about half the diameter of Earth. Honestly, about all you’re going to see of Mars is an orange-red dot and that’s about it. About every two years Earth and Mars are at their minimum distance to each other in the solar system and that’s when it worth spending more time spying on Mars. Unfortunately that won’t happen again until 2016.
Saturn is one of the coolest things to see through a telescope of just about any size. You can easily see its 130,000-mile-plus ring system made up of ice crystals as well as ice covered pebbles, rocks, and boulders up to the size of school buses. Keep in mind that this ring system is only about 50 miles thick. One or two of Saturn’s moons got too close to the main planet a long time ago and were ripped to shreds by tidal forces. The bits and pieces are held together in the ring system by other moons acting as gravitational “shepherds”.
Incidentally, through a small telescope you should be able to see some of Saturn’s sixty plus moons that resemble tiny stars swarming all around Saturn. A notably bright one is Titan, Saturn’s largest moon, which is actually larger than the planet Mercury. You can’t see it with even a huge backyard telescope, but Titan has lakes and oceans of liquid methane. Another oneof Saturn’s much smaller moons, Enceladus, has liquid water in its interior and occasionally someof it spews out into space through cracks on its surface.
The only problem with seeing Saturn with any size telescope this summer is that it’s very low in the sky, and because of that we have to view it behind more of Earth’s blurring atmosphere that can really muddy up the view. It’s still a wonderful telescope target. Just make sure you take long continuous views through your scope. The longer you look, the better chance you have of getting a clearer view.
As good as the Mars-Saturn dance is in the evening, make absolutely sure you check out Venus and Jupiter in the early morning twilight, low in the east-northeastern sky. Set your alarm. It’s worth it. Even if you’re not all that excited about stargazing you’ll love what you’ll see. Venus and Jupiter are much brighter than Mars and Saturn and they’re practically on top of each other. They are less than a degree apart early this week. These two are the brightest planets available in the night sky and this is the closest they have been to each other since 2000.
Obviously Venus and Jupiter are nowhere near each other physically. Jupiter, the largest planet in our solar system with a girth of over 88,000 miles, is almost 600 million miles from Earth while Venus is about 150 million miles away. Just as it is with Mars and Saturn, Jupiter is far more interesting through a telescope even though it’s much farther away. You can see up to four of its larger moons lined up on either side of the planet and you may see some of the Jovian planet’s cloud bands. Even though it’s much brighter, Venus is a big nothing. All you’ll see is a white ovalish disk since Venus is completely covered in clouds made up of sulfuric acid.
Honestly, even though Jupiter’s a better telescope target it will be blurry, because both planets are so close to the horizon and morning twilight partially washes them out. It’s still fun to be able to see them both in the same field of view through your telescope. In fact, if you hold out your thumb at arm’s length early this week you can easily cover up two other worlds. Take a look at these two early this week because they will start to separate noticeably by week’s end.
Conjunctions of the planets with each other and the moon occur because all of the planets, including our Earth, orbit the sun in their individual orbits in nearly the same plane. While they’re not something you can see all the time, conjunctions do happen fairly frequently although some are much better than others, as it is this week. Don’t miss either one.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications available at bookstores at http://www.adventurepublications.net