The moon and Venus can take you to faraway places

In the early evening twilight skies this week, you have an excellent opportunity to see three other planets in our solar system, two of which are way out there. We also have a new crescent moon adding to the celestial show! Let’s hope and pray for some clear or at least transparent enough skies.

Let me start by telling you about the feature presentation this week, the Venus and moon show. They’ll be lighting up the early evening low in the southwest Marshall sky this Sunday, Monday and Tuesday. Don’t miss it!

Since late this past autumn there’s been an extremely bright “star” in the low southwest Marshall sky. That’s not a star, it’s the planet Venus. There are two reasons it’s so brilliant. One is that it’s pretty close to Earth, currently just over 104 million miles away. The main reason for its brilliance, though, is that it’s entirely shrouded by a thick and very reflective cloud cover. You certainly wouldn’t want to fly into those clouds. They’re made up of mostly carbon dioxide laced with carbon monoxide and sulphuric acid rain. It’s not exactly the friendly skies.

As bright as Venus is, it’s not that great of a telescope target because of the overwhelming cloud cover. It will appear as a blinding oval-ish disk, resembling a gibbous moon. Since Venus’s orbit around the sun is inside the Earth’s orbit, it goes through phases just like our moon does.

On Sunday evening, Jan. 26, look a little below Venus for a very thin crescent moon, barely above the horizon. Make sure you look as early as you can because the moon will dip below the horizon a little after 6:30 p.m.

On Monday evening the 27th, you’ll easily see the slightly fatter crescent a little closer to Venus, hanging just below the planet named after the Roman goddess of love. Even if you’re not all that much into stargazing you’ll be impressed. On Tuesday evening, you’ll be equally impressed as an even fatter crescent moon will be perched to the upper left of Venus.

To enhance the Venus and moon celestial hugging, we’ll also be experiencing a phenomenon known as “Earthshine.” Not only will you see the sunlit crescent slice of the moon’s disk, but you’ll also see the rest of the disk bathed in a soft grey light. That pale light is sunlight bouncing off the highly reflective Earth, and then onto the Moon. Call it secondhand sunlight.

Unless you are an expert stargazer, it’s usually way too challenging to locate Neptune among the stars. This week, however, you can use Venus to spot Neptune, the farthest official planet from the sun since both planets are in nearly in the same line of sight. On Monday night, Neptune will be almost “touching” Venus, less than a half a degree away to the lower right. Neptune will be much too faint to see with just your eyes, but with a pair of binoculars, I can just about guarantee you’ll see Neptune. It’s so close to Venus in the sky that you’ll easily see both planets in the same field of view. Neptune will be the next brightest starlike object to the lower right of Venus. It may also be sporting a subtle blue-green tinge.

Neptune, one of the outer gas giant planets of our solar system, is much, much farther away than Venus, nearly 2.8 billion miles away. It’s so far away that it takes more than four hours for its light to reach Earth.

Later on this week, on Friday night, Jan. 31, you can use the nearly first quarter (half) moon to locate Uranus, another blueish-greenish gas giant planet of our outer solar system. Uranus will be the next brightest star-like object to the upper right of the moon, about five degrees away. Five degrees is about half the width of one of your fists held at arm’s length. Uranus, although not a hop, skip, and a jump away, is a little closer to Earth than Neptune, only about 1.8 billion miles away!

The reason we can use the moon and brighter planets to locate more distant fainter planets is that all of the planets in our solar system, including our moon, orbit around the sun in more or less the same mathematical plane. As a result, planets we see from Earth all take more or less the same slow path against the background stars in our sky as they make their way around the sun. That makes spotting distant solar system planets like Uranus and Neptune a little easier at times.

By the way, if you see Uranus on Friday night or any other night, know that Uranus wasn’t its original name. The great English astronomer William Hershel discovered Uranus in 1781. When he found this new planet, he named it planet George in honor of the British king at the time. Obviously that name didn’t pass the test of time!

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is also the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and at  adventurepublications.


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