Dennis Mammana | Stargazers: Rise early for an excellent cosmic show
This week, four planets and the moon are performing a wonderful planetary dance in the eastern sky at dawn, and if you've got binoculars or a small telescope, their performance will be even more impressive.
The sky show begins on the mornings of Jan. 6, and Jan. 7, with the planets Mars and Jupiter. Jupiter, of course, is the largest of all solar system planets, at 11 times larger than our own Earth. It appears so bright in the sky because its huge orb is composed of highly reflective clouds. Mars, by comparison, is a tiny rocky world about half the size of Earth and will appear dim by comparison.
Of course, Jupiter and Mars are many millions of miles apart, but on those mornings, these two distant worlds will appear roughly along the same line of sight. In fact, anyone aiming a small telescope in their direction will easily be able to see them both in the same low-powered field of view.
Within only a few days, Mars and Jupiter will appear to separate as they travel on their separate orbits, and on the morning of Jan. 10, the waning crescent moon will enter the scene and lie just above the pair. By the following morning, Jan. 12, it will form a tight triangle with Mars and Jupiter.
This would be a good time to begin watching the show unfolding much closer to the southeastern horizon. If you've got a clear view in that direction, you may spot the planets Saturn, the farthest planet visible to the unaided eye from Earth, and brighter Mercury, the innermost world of our solar system. Being the nearest planet to the sun, Mercury hovers fairly close to the sun and moves rather quickly, whipping around its orbit every 88 Earth days; as such, it rarely appears far enough above our dusk or dawn horizon to be seen easily.
Keep an eye on these two worlds for the next few mornings, because their relative positions will change quite rapidly. On the mornings of Jan. 12, and Jan, 13, these two bodies may also appear in the same field of view of a low-power telescope.
One thing you might notice is that Mercury and Saturn appear to twinkle. Now, this seemingly contradicts what most of us learned in elementary school — that stars twinkle but planets don't. This is one of those many facts we learned that just is not true.
The twinkling we see is the result of unstable air moving in front of distant lights and causing them to appear to shimmer. We see this frequently when we look over a hot campfire; distant objects appear to be bouncing around. When a star's light passes through our turbulent atmosphere, its thin light beam is also distorted and bent — thousands of times per second — and we see the stars as appearing to twinkle. The same is true for planets, mostly when they appear near the horizon. Don't miss rising early for this week's cosmic dance. ... Your efforts will surely be rewarded!
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