If you’re just starting out in astronomy, observing the Moon is a good place to start! The Earth’s only natural satellite is a familiar sight in our night skies, but have you ever taken a closer look? Read on to find out what makes the Moon special. Spoiler alert: it’s not made of cheese!
The Changing Moon
Although big and bright, the Moon isn’t always easy to spot. It’s a common misconception that the Moon is always visible at nighttime, much like the way the Sun is in the sky in the day. But our day and night are caused by our movement around the Sun; the movement of the Moon is completely different! It orbits the Earth, completing one cycle every 28 days. The Moon tends to rise about 20-40 minutes later each day, and resets each cycle. It can sometimes be seen in the daytime sky. This also means it isn’t always visible at night. Be sure to check out when the Moon rises and sets before going out to see it!
We can also see evidence of the lunar cycle in the phases of the Moon. You may have noticed that the Moon appears in different shapes and sizes on different nights. This is because the only things in the universe that can give off their own light are stars. Planets and moons in our solar system reflect light from the Sun towards the Earth, so that we can see them. But only half of the Moon is facing the Sun at any one time, so only this half is lit. The Earth works the same way; half the planet has daylight at any one time.
Our Moon is very special, because it is tidally locked. This means that the same side always faces the Earth. When this side matches up with the part of the Moon facing the Sun, it’s entirely lit and we see the full moon. But as the Moon moves in its orbit, the part that’s facing the Sun changes. Sometimes only one half of the side we can see is lit, and sometimes just a little slither. When the lit side is facing away from us, the Moon appears as a dark shape in the sky; the new moon. All these different sizes of the Moon are its phases!
Features of the Moon
At first glance, the Moon can look pretty plain. But if you look closer, you’ll see it has a huge variety of features visible on its surface. The easiest things to make out are the dark patches littered across it. These are called maria, or seas. They were named by scientists who thought they contained water, but in fact they are full of dried volcanic material.
You can also see lots of craters on the Moon. These are round indents in the surface caused by the impact of rocks from space. They tend to be lighter in colour, as their ridges are taller. Other light areas on the Moon may be highlands; large mountain ranges that reach up to half the height of Mount Everest!
If you’re observing the moon with a telescope or binoculars, take a look at the line between the lit side and the dark side. This is called the terminator, and the shadows it casts can make it easier to see the features along it.
Observing the Moon
So, what’s the best way to observe the moon? The massive advantage of its size in the sky means that even with the naked eye, you can make out some of the maria on the surface. Binoculars or a telescope allows for even greater detail, and will make it much easier to identify specific features. With binoculars, you can make out large craters and mountain ranges. A telescopic view gives you access to lots of different features, and the dramatic shadows they cast near the terminator.
So get out there and explore the wonderful world of our Moon! Who knows what you’ll find by observing the Moon?