Our planet Earth isn’t the only ball of rock whizzing through space. There are 7 other major planets going around the Sun — Mercury, Venus, Mars, and so on. Then there’s our Moon. It’s a quarter million miles away, which sounds far. But someone figured out that if you lined up all the other planets, they’d fit perfectly between us and the Moon! They’d leave only 5,000 miles extra, so even Pluto could fit if it still counted as a major planet.

*Wee ones:* What shape are Earth, the Moon, and our planet friends?

*Little kids:* How many objects can you count in the photo of Earth, Moon, and the planets? *Bonus:* Mercury is about 3,000 miles wide, Venus is about 7,000, and Mars is about 4,000. How much of that line-up do those 3 cover together? (*Hint:* You can add 3 thousand, 7 thousand, and so on as if you were adding 3 apples, 7 apples…)

*Big kids:* Jupiter is almost 300,000 miles around at its widest point. How many 3,000-mile-wide Americas could you wrap around Jupiter? *Bonus:* If Earth is 8,000 miles wide and Jupiter is 88,000 miles wide, how many times as wide is Jupiter?

*The sky’s the limit — for real:* If you wanted to line up the 4 gas giants (Jupiter, Saturn, Uranus and Neptune) in the last 4 slots but in some other order, how many other ways could you line them up?

Answers:

*Wee ones:* They are spheres, another word for ball. From the side, they look like circles.

*Little kids:* 9 objects. *Bonus:* 14,000 miles, nowhere near the width of the next biggest planet after Earth (Neptune at over 30,000 miles).

*Big kids:* 100 of them. *Bonus:* 11 times as wide.

*The sky’s the limit:* 23 other ways. If you keep Jupiter first, there are 3 planets that can go in the next slot; for each of those 3 choices you can put either of the remaining 2 planets in the next slot, leaving the last one for the last spot. That gives you 3x2x1 or 6 orders that put Jupiter first. But you can do this with any of the 4 planets coming first, so that gives you 4x3x2x1, or 24 orders. The one shown here is one of them, so that gives us 23 other ways.

And thank you Emily B. for sending these amazing photos!

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.