Earth passed by Jupiter yesterday. Now, we’re beginning to leave the giant planet behind. We’ll loop past it again early next year.

That passage is known as opposition – Jupiter lines up opposite the Sun in our sky. It’s closest to us then, so it shines brightest for the year. And it’s in view all night.

Jupiter is much farther from the Sun than Earth is, so it takes about 12 years to complete a single orbit. Earth follows a much shorter path around the Sun, and it moves faster. So it passes Jupiter every 13 months.

As we approach Jupiter, the planet stops its normal eastward motion against the background of stars. For a while, it moves backward – a period known as retrograde.

Jupiter itself doesn’t change direction. Instead, the shift is a result of our changing viewing angle. It’s like passing a car on the highway. For a little bit, the other car looks like it’s moving in reverse compared to the background of buildings and trees. As the gap opens, though, it appears to resume its forward motion. Jupiter will reach that point on March 11th – shifting gears as it circles the Sun.

Jupiter looks like a brilliant star – brighter than any other planet or star in the night sky now. The twin stars of Gemini are close by. Pollux, the brighter twin, is close to the left of Jupiter at nightfall. Castor is farther to the upper left. The whole group soars high across the south during the night.

Script by Damond Benningfield