What is a “day,” anyway? You’re standing on a REALLY big ball called Earth. and a day is the time it takes to spin around to face the Sun again each morning. So which planet has the longest day? It is Venus, which takes a pokey 243 Earth days to spin once. Venus’ day is longer than its year – the time it goes once around the Sun – which is only 224 of our days. So on Venus, you celebrate your birthday every day!
Wee ones: All 8 planets are shaped like balls, or “spheres.” Do you see any ball shapes in the room around you?
Little kids: The planet Uranus’ day is 17 hours long, while Neptune’s is 16 hours. Which one takes longer to spin once? Bonus: How much longer is the longer day?
Big kids: If at 7:00 pm tonight it’s noon somewhere on Neptune, at what Earth time will an alien on that spot have noon again? (Reminder: Neptune’s day takes 16 hours.) Bonus: Mercury’s day is 59 Earth-days long. If someone there has sunrise there today, on what day will he see the next sunrise? (Reminder if needed: July and August each have 31 days.)
The sky’s the limit: If someone sees sunrise on Venus today (July 28), in what Earth month will that person see sunrise next (243 Earth days from now)? Or feel free to figure out the exact day!
Wee ones: Different for everyone…look around your room!
Little kids: Uranus takes longer. Bonus: 1 hour longer.
Big kids: At 11:00 the next morning. Bonus: September 25, because Sept. 28 would be 62 days (31 + 31).
The sky’s the limit: Our months have about 30 days in them, so 243 days is about 8 months, which would be end of March 2025. It turns out to be exactly 8 months: Venus will end its “today” on March 28, 2025.