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Moon and Venus

June 19, 2017

One of the loveliest events in the night sky is a close alignment of the Moon and the planet Venus. And just such an alignment takes place the next couple of days before and during dawn. Venus, the brilliant “morning star,” stands to the left of the Moon at first light tomorrow, and about the same distance to the upper right of the Moon on Wednesday.

A close alignment between two or more astronomical objects is called a conjunction. The Moon has several of them every month, because it makes a full loop against the background of stars and planets.

And it’s always the same roster of companions, because the Moon follows a narrow path across the sky. In fact, it stays close to the Sun’s path, known as the ecliptic. Several bright stars lie near the ecliptic, and so do the bright planets. So the Moon swings past each of these objects every month, staging beautiful conjunctions.

The Moon also has conjunctions with the Sun. Most months, these conjunctions are invisible. The Moon’s path is tilted just a bit with respect to the ecliptic, so the Moon usually swings just above or below the Sun, where it’s lost in the glare.

In August, though, the Moon will be crossing the ecliptic just as it passes the Sun. That will create the most beautiful of all astronomical encounters: a total solar eclipse. Its path will cross the United States from Oregon to South Carolina — a beautiful conjunction between the Moon and Sun.

More about the Sun tomorrow.


Script by Damond Benningfield

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