Today's post in this What Is series focuses on a moon. Not THE Moon. THE Moon is the moon that orbits the Earth. Here I'm focusing on the general definition of any moon. We know a planet must orbit the Sun, be spherical in shape, and cleared its area of debris, but what does it take to be a moon?
 |
| The two Martian moons, Phobos and Deimos, taken by NASA/JPL/USGS |
Shown above are the two moons of Mars, Phobos and Deimos. A moon is any natural object orbiting a planet, dwarf planet, or even asteroids. Basically if the object orbits something other than the Sun, it is a moon. Earth has one moon, Mars has two moons, and Jupiter has 67 moons (as of 2018), for example. Some moons are very large and spherical in shape. This includes our Moon and the four Galilean moons of Jupiter, among others. Most moons are much smaller and look more similar to Phobos and Deimos. Most moons are just a few miles in size and are more irregular or lumpy in shape.
Artificial satellites we put in place to orbit Earth or other planets are not moons. To be a moon, the object must be natural.
So there you go. Moons are natural objects that orbit other objects in the solar system. What about moons in other solar systems? They are called exomoons because they orbit exoplanets. :-)
No comments:
Post a Comment