When early skywatchers looked into the night sky, they saw the stately progression of the stars. The stars march across the sky together, always returning to view at the same time each year. That led to ideas about the nature of the stars: lamps hung from a dark dome, for example, or holes in the dome letting in the light of heaven beyond.

There was a problem, though. A few especially bright lights moved at a different pace from the rest — and even from each other. They sometimes reversed direction, or even stood still. They got noticeably brighter and fainter, too. The Greeks called these oddballs “planets” — a word that means “wanderers.”

Figuring out what was happening with the planets helped us understand the workings of the entire cosmos. The planets are close by, and they move around the Sun, just as Earth does. In fact, they’re siblings of Earth. The other lights — the stars — are much, much farther. They form a distant background — a canvas for the “wandering” planets.

And one of the planets is at its best for the entire year this week. Jupiter is at opposition — it lines up opposite the Sun. It rises at sunset and is in view all night. And it’s closest for the year, too, so it shines brightest. It looks like a major star low in the east-southeast at nightfall — brighter than any true star. It’s on the border between Capricornus and Aquarius — the backdrop for a brilliant planet.

More tomorrow.
 

Script by Damond Benningfield