Wednesday, November 9, 2011

You Will Be a Moon Expert in Five Minutes (well, half a Moon Expert)...

Thanks for coming back for the meat-and-potatoes part of the Moon talk. This episode, we'll get the map of the Moon memorized so that the next time you see the Moon in the night sky, you'll be able to impress your friends, family, and passers-by with your insanely-great knowledge of the Moon.

Here's the best part: you'll only have to learn HALF of the map of the Moon to be an expert. Why? You know this already: we on Earth only see one half of the Moon's surface. So, we'll only go over the NEAR side of the Moon. The FAR side - - the side we never see - - is mostly populated by hundreds of thousands of craters, like this:
And it's mostly a bunch of craters with really long Russian names (they were the first around the back of the Moon with a satellite, so hey -- naming rights!) so we'll just skip that part.

Okay, back to the Near side. When we look at the Near side of the Moon, we see mostly dark areas, punctuated by a couple of lighter, dusty cratered areas. Like this:

The dark areas are called by the Italian word for "sea," which is "Mare" (remember Galileo and his telescope? Hey -- naming rights!) The dark areas were given Italian names, and form the major identification structure of where things are on the Moon. It's sort of like talking about continents on Earth.

Now, it looks like there are a lot of mares on the Moon, and that might seem difficult to remember. However, if you break the Moon down into regions, it becomes super-easy to remember what is where on the map of the Moon.

First, a quick note about directions: when you're looking at the Moon in the Northern Hemisphere, north on the Moon is "up," south is "down," west is to the left, and east is to the right. So, let's think about it like this:

The secret to learn the map of the Moon is to learn this ditty about the Moon maria:

"Five on the East Side,
Five on the West Side,
Two in the Middle
and an Ocean out West"

Say it out loud. Don't worry - - nobody will notice. Say it:

"Five on the East Side,
Five on the West Side,
Two in the Middle
and an Ocean out West"

Okay, let's not learn the whole Moon at once - - we'll start with the East side of the Moon:

The East side of the Moon, the part that the New Moon first lights up at the start of the lunar month, has *five* major maria we can spot with the naked eye. Here's a bunch of circles to highlight the five maria:

Let's take the Moon away so we can focus on the maria circles:

So, there's one really circular mare on the upper right, three connected seas in the middle, and then a stretched-out one at the bottom. See the groupings? 1, then 3, then 1 more.

That one circle at the top right is the Sea of CRISES, or Mare Crisium.

See? You've learned the name of a lunar mare. Crises - - think of it as  NEW ENGLAND Crises, and it'll be easy to remember - -because it's waay up in the northeast part of the Moon, like New England is on a map of the United States. Crises - - you've got that one down pat now.
Let's get on with the clump of three. These are the "ITY" seas because their names all finish with "ity." Look:

There's the Sea of Serenity, the Sea of Tranquility (Neil! Buzz!), and the Sea of Fertility. Serenity, Tranquility, Fertility. How to remember this stuff? STUFF. Stuff - that's it! STF - Serenity, Tranquility, Fertility. Think of it as a sandwich - -the STUFF goes in the middle.

Last one on the East side of the Moon is the Sea of Nectar:

Nectar - - how to remember that? Nectar DRIPS down to the bottom, so the Sea of Nectar is at the bottom of the Moon's Eastern maria. The Sea of Nectar is also the oldest mare visible on the Moon, so it's going to be at the BOTTOM of the totem pole when it comes to stacking the maria on a timeline. 

Let's go over those East side maria again: Sea of Crises at the far northeast, then the STUFF in the middle (Serenity, Tranquility, Fertility), and then the dripping Sea of Nectar at the bottom. Done with half the Near side's maria!

We'll bring the map back in for a moment so that you can picture how it looks in the sky with the names (but of course you know these names now so you won't need a reference when you look at the Moon in the sky later, right?)

Isn't it something that you know all these names in your head now? I was going to continue with the west maria, but let's pause here for right now and pick up the west side of the Moon next time. You're doing really well sticking with this post all the way to the bottom! Come back again for the west side.


  1. Terrific Mnenonics! I memorized them by brute force when I was a kid, but this will be a very helpful refresher. Looking forward to the left side.

  2. Glad you're enjoying it, Brian. I think we both learned Moon geography the same way: staring at maps on the living room floor while John Chancellor or Cronkite, or Jules Bergman droned on about Apollo on TV. Back in my college days I used to try to teach the map of the Moon to my friends, but to no avail.

    I continue to be amazed at how people can see the Moon in the sky every month of their lives and not ever wonder what the names of all those spots on the Moon were. Sigh.