• A. Jupiter
  • B. Mars
  • C. Saturn
  • D. Venus

💡 Need a hint?

Don’t think about the gas giants — they actually spin incredibly fast. The planet you’re looking for has a notably slow rotation speed and a peculiarity in the direction of its movement.

✅ View the answer

The correct answer is D. Venus.

A day on Venus, measured as one complete rotation on its own axis, lasts approximately 243 Earth days. That’s longer than a year on Venus, since Venus only takes 225 Earth days to complete one orbit around the Sun. Bizarre, but true.

And there’s something else: Venus rotates in the opposite direction compared to most other planets. Someone standing on Venus would see the Sun rise in the west and set in the east.

📚 More background information

The Slowest Spinner in the Solar System

Venus is an oddity in several ways. It is the hottest planet in our solar system — even hotter than Mercury, which sits much closer to the Sun. The average surface temperature is around 465 degrees Celsius, the result of an atmosphere thick with carbon dioxide that traps heat as though there has never been a way out. That greenhouse effect is so extreme that the early Soviet space probes that landed on Venus survived only a few minutes before the heat and pressure literally crushed them.

Why Does Venus Rotate So Slowly?

Honestly, we don’t know for certain. The most popular explanation is an ancient collision with a large celestial body, something that would have drastically slowed and reversed its rotation. However, some planetary scientists also point to atmospheric friction as a contributing factor. The debate is still ongoing.

How Does This Compare to Other Planets?

Jupiter sits at the opposite extreme: its day lasts only about 10 hours. Mars has a day of 24 hours and 37 minutes — nearly identical to ours. And Mercury? Its day lasts around 59 Earth days, which sounds impressively slow until you realize that Venus surpasses that more than fourfold. Saturn also rotates in approximately 10.5 hours.

One Striking Detail

On Venus, a day is longer than a year. The planet orbits the Sun faster than it rotates on its own axis, which completely defies your intuition when you stop to think about it.

Venus Through the Ages

Venus has been a source of fascination for centuries, simply because it is the brightest object in the sky after the Sun and the Moon. Many ancient cultures associated it with goddesses of love and beauty. It wasn’t until the twentieth century, through the Soviet Venera missions, that it became clear just how inhospitable the planet truly is. That romantic name, it turns out, doesn’t quite fit.