Author Archives: maryjane

When I go glamping with my grandgirls later this summer, I want to be able to teach them about the movement of the sun, moon, and stars in the wide-open skies. But the nature of how it all works can be confusing. I recently ran across a basketball analogy that put everything in perspective. Since my son-in-law, Lucas, was a basketball coach, the girls are familiar with the game, so it will be a great way for them to remember how the moon orbits around the Earth.

First, picture a basketball court. We’ll scale the Earth down to the size of a basketball and place it in the basket. That will make the moon the size of a tennis ball. The moon, then, basically orbits the Earth at the 3-point line (that’s the line that looks like a circle about 23’ from the basket where you can’t believe Steph Curry just made a basket from).

Note: Because the moon’s orbit is really elliptic and not exactly circular, it extends away from the 3-point line at its apogee (furthest point from the Earth) and perigee (nearest point to the Earth) at about the length of a tennis racket. But I might save this little tidbit for later. No need to confuse the issue (or Nanny Jane!).

Fun fact: At this same scale (basketball/tennis ball), the sun is about the size of a very large hot-air balloon and it’s about 1 3/4 miles away from the basket. The sun and moon appear to be the same size when we look at them in the sky. However, the sun is 400 times larger than the moon. So why does it appear the same size as the moon? Because it’s nearly 400 times further from the Earth!