Venus and Jupiter

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• 28 of 1966
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The brightest "nightlights" other than the Moon are hanging out together in the southeast at dawn the next few mornings. They're quite low in the sky, so you need a clear horizon to find them. But they're so bright that they stand out.

The brighter of the two is Venus, which is wrapping up its run as the "morning star." It'll remain in the morning sky for several more months, but it's gradually dropping closer and closer to the Sun. Within a few weeks, it'll get lost in the Sun's glare. Venus will pass behind the Sun in the spring, and climb into view in the evening sky in the fall.

Jupiter is below Venus tomorrow, but it won't stay there for long. It's pulling away from the Sun, so it's climbing into better view each morning. As winter and spring roll by, Jupiter will put on a grand showing, rising earlier and remaining visible for a longer part of the night.

Jupiter can do that because it's a superior planet -- its orbit around the Sun is outside the orbit of our own Earth. From that position, Jupiter can cross the entire night sky, even shining on us at midnight.

Venus, on the other hand, is an inferior planet -- its orbit is inside Earth's. As a result, it can move only a limited distance from the Sun in our sky. It can shine as a morning star or evening star, but not a midnight one.

Look for Venus quite low in the southeast at first light, with Jupiter a little below it. More on this bright duo tomorrow.

Script by Damond Benningfield, Copyright 2007

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