The moon’s been rounding up this week on its way to full. April’s full moon is called the Pink Moon. It’s named for moss pink, a pink-colored phlox that’s one of the earliest spring flowers. Funny thing is, the full moon often comes up a little pink. Pink, red, orange. They’re all warm colors. The dense air we have to look through when viewing celestial objects at low elevation scatters away the purples, blues and greens, leaving just the warm colors.
Full moon occurs around 8 p.m. CDT Sunday evening, April 29. As with all full moons, the pink one will rise close to sunset, top the sky around 1 a.m. and set around sunrise the next morning. Like certain people and birds, it’s up all night. When you stare at the full moon, you’ll see spots. Really, you will. Those dark spots are the lunar “seas,” which used to be giant craters punched in the lunar crust by good-sized asteroids.
Basaltic lava rose up from fissures in the floor of these impacts and paved them over. The average depth of the dark basalts is around a half-mile. Rich in titanium, the rock is dark compared to the lunar highlands, the original and ancient lunar crust that surrounds them. The contrast between dark and light tempts us to see patterns like faces and animals the same way we see them in clouds or floor tiles.
That’s part of the fun of a full moon. Another is watching the moon rise. You never know quite what color you’ll see or what shape. It’s common knowledge the moon looks squashed when it rises. Kind of like a watermelon. That’s due to refraction, a prism-like property of the air that bends the light coming from the bottom of the rising moon more strongly upward, “squeezing” it into the top half to make an oval.
But it doesn’t end there. Sometimes the atmosphere near the horizon is layered according to temperature. As the moon rises through the layers, it can appear pinched, crenulated or even sliced. All kinds of screwy stuff can happen, the reason every moonrise possesses an element of surprise. To find out when the moon comes up for your location, so you can be sure not to miss the Pink Moon, click here.
You’re going to notice a second very bright object in the night sky Sunday night. That’s Jupiter, which is now about as close to Earth as it will get this year. Hey, only 410.8 million miles (661 million km)! Traveling 186,000 miles a second, it takes Jupiter’s light 37 minutes to reach our eyes. They’ll be 8° apart or a little less than the width of your fist held at arm’s length. The moon rises first (around 8) followed by Jupiter about an hour later. On the following night, April 30th, they’ll still be near one another.
For more cool stuff to see on the moon during the coming nights, check out my lunar observing guide for small telescopes.