Venus Has a Day Longer Than Its Year and Its Sun Rises in the West

Venus breaks the rules of planetary timekeeping.

One full spin on its axis takes about 243 Earth days. But one trip around the Sun takes only about 225 Earth days. That means Venus’s rotation day is longer than its year.

It gets stranger: Venus rotates in the opposite direction from most planets. If you could somehow stand on its crushingly hot surface, wrapped in clouds of sulfuric acid, the Sun would rise in the west and set in the east.

Because of that backward spin, a sunrise-to-sunrise “solar day” on Venus is about 117 Earth days still wildly long, but not the same as its slow full rotation.

Venus is almost Earth’s size, but its clock runs like it was assembled by a cosmic prankster.

On Venus, the calendar outruns the clock.

Venus sounds impossible at first: its day is longer than its year.

But the trick is that there are two different ways to talk about a “day.”

A rotation day is how long a planet takes to spin once on its axis. On Venus, that takes about 243 Earth days.

A solar day is how long it takes for the Sun to return to the same place in the sky — sunrise to sunrise. Because Venus spins backward while also moving around the Sun, that works out to about 117 Earth days.

So Venus does not just move slowly. It moves strangely.

Its year is about 225 Earth days, its full spin takes about 243 Earth days, and its sunrise-to-sunrise day is about 117 Earth days. Add in the fact that the Sun would rise in the west, and Venus becomes one of the strangest clocks in the solar system.

Earth gives us a sunrise every morning.

Venus makes you wait almost four months.