This image, made by Greg Egan, shows the orbit of Venus.
Look down on the plane of the Solar System from above the Earth. Track the Earth so it always appears directly below you, but don’t turn along with it. With the passage of each year, you will see the Sun go around the Earth. As the Sun goes around the Earth 8 times, Venus goes around the Sun 13 times, and traces out the pretty curve shown here.
It’s called the pentagram of Venus, because it has 5 ‘lobes’ where Venus makes its closest approach to Earth. At each closest approach, Venus move backwards compared to its usual motion across the sky: this is called retrograde motion.
Actually, what I just said is only approximately true. The Earth orbits the Sun once every
days. Venus orbits the Sun once every
days. So, Venus orbits…
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