Observational astronomers hate the moon. This might be surprising to some of you 鈥� after all, the moon is gorgeous, it鈥檚 the closest astronomical object we can observe and the dominant feature of the night sky on Earth. But that very spotlight is the problem: when the moon is out, its glare can hide nearly everything else. When you are looking for tiny details or deep-sky objects, that is a problem.
Even in just the next couple of months, there are two meteor showers that will each happen within a few days of the full moon, rendering them practically invisible. If you live in a bright city like I do and there is also a full moon? Forget about seeing just about anything else in the sky.
But as tempting as it is, I won鈥檛 spend this entire column hating on the moon. After all, no matter how many times you have looked at it, there is always more to see.
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You might think the best time to observe the moon is during its full phase, when its entire face is lit by sunlight, but that isn鈥檛 quite right. See, the surface of the moon doesn鈥檛 vary all that much in colour, so looking at it when it is fully bathed in light is a bit like looking down on a desert scene at high noon. You can see a few variations, but the full drama of the landscape is best seen when the sun is shining on the moon from an angle, so the moon isn鈥檛 full and the relief of the landscape is brought out by the shadows.
The best place to look if you want to see those details is the terminator 鈥� the line between light and shadow. That鈥檚 the inside curve of a crescent moon or right in the middle of a half-moon, the spot where the sunrise or sunset is happening. At that point, you can see long shadows cast by boulders over the lunar mare, bright spots where the light hits the edge of a crater just right and jagged ridges running through smooth plains.
All of these features let us bear witness to the 4.5-billion-year history of our solar system, a history whose signs have been largely washed away on Earth by plate tectonics, running water and life. For every crater on the moon, there should be more than one on our own planet that has probably disappeared by now.
If you want to get really into the details of the lunar surface, I recommend trying to draw it. Not the whole moon, just as small a section as you can manage with whatever form of magnification you have. Colour in the darkest areas first, then move up a shade and draw the shapes of the next-darkest spots. Don鈥檛 try to draw a portrait of the moon, just try to get the shapes right, and the shades of grey with respect to one another.
You will find that the lunar surface has surprising complexity. I am extremely bad at drawing and somehow I have drawn a picture or two of parts of the moon that, in my opinion, were actually good. So don鈥檛 let a lack of artistic aptitude stop you! Give it a go, and maybe email me what you draw?
Leah Crane is a features editor at New Scientist based in Chicago. You can reach her at launchpad@newscientist.com
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