Moon Craters

When is the last time you took a good look at the moon? There is a full moon coming up this Wednesday, so now might be the time to become a little more acquainted with the man in the moon and moon’s other features.

If you are lucky enough to have access to a telescope, great! But if you don’t, a lot of the moon’s features can be observed even with a good pair of binoculars.

One of the more interesting aspects of the moon’s surface are the craters, and there are lots of them. Astronomers have documented over 5,000 craters on the moon, ranging from diameters of a few feet to over a thousand miles. The moon has taken a pummeling from asteroids, comets, and other objects, and the craters are the remnants of those collisions.

An asteroid or comet striking a planet or moon is not unusual. All of the planets and moons in our solar system have been hit by an asteroid or comet. The earth, of course is no exception. Perhaps the most widely known crater in the United States is the Barringer Crater in Arizona which is about a mile wide and over 500 feet deep. And of course there are others.

But why are there so many prominent craters on the moon compared to the earth.

The earth and moon are about the same age, roughly 4.5 billion years old, so age is not the difference.

Many asteroids on a collision course with the earth burn up while passing through the earth’s atmosphere. The moon doesn’t have an atmosphere, so all of the asteroids hit the moon’s surface. There is one other important factor here. Unlike here on earth, where wind and rain erode the craters, the moon has no wind or rain, so the craters are permanent.

These craters are not formed by love taps. Astronomers estimate that these objects may have been traveling around 43,000 mph. At that speed, the impact would form a crater 10-20 times as large as the diameter of the object.

The largest crater on the moon is a staggering 1,300 miles across, called the South Pole-Aitken basin, it actually is on the far side of the moon, so you won’t be able to see that!

Chuck Lura

Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Minot State University-Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.