If you’re looking up into the night sky, then you’re going to see thousands of stars spread across the landscape. Amongst them is the moon, which is the brightest objects in our sky at nighttime. Because of our close proximity to the Moon, we have actually been able to go there and visit – this means that we know a lot about the Moon. But what exactly is it? Well, let’s have a look.
Is the Moon a Star, a Planet or a Satellite?
The answer is that the moon is not a star, and the moon is not a planet either. The moon is actually defined as an “astronomical body” and is technically a satellite. It is made up of many different materials, with its core made up of iron and its crust made up of rocky materials. It is also a satellite, as a satellite is defined as anything which orbits a planet or star.
You can be forgiven for thinking that the moon might be a star or a planet. It’s bright, just like a star is. However, the stars that are in our night sky are actually all light years away from us, and are not even in our solar system. They’re all like our Sun, which is the only star in our solar system – in fact, many of them are a lot bigger than our Sun, but they’re just so far away!
And it would be easy to think that the moon is a planet too – it’s not much smaller than the planet Mercury, so it’s definitely sizeable enough. However, a planet is defined as an object that orbits the Sun, which is something that the moon doesn’t do. A planet is also defined as something which dominates the gravity within it’s vicinity, which again, isn’t something that the moon does.
However, what the Moon does do successfully is orbit the Earth. So, it is defined as a satellite, which is anything that orbits either a planet, or the Sun. Our planets are also defined as satellites too, because they orbit around the Sun, which is a star! You can look at more facts about the Moon, or read more about why it’s technically a satellite.
Why is the moon a satellite?
The reason that the moon is a satellite is because it orbits around the planet Earth – it is the Earth’s only natural satellite! However, I guess you’re wondering just why the moon continues to orbit around the Earth and doesn’t just float off somewhere else!
The only answer for this is gravity. Gravity is what keeps the moon orbiting the Earth, and has done since the moon was formed around 4.5 billion years ago! Astronomers estimate that the moon was formed just after the solar system was formed.
Anyway, the gravitational pull of the Earth is what makes the moon orbit it. The moon is moving anyway, and if it wasn’t in Earth’s vicinity, it would be moving in a certain direction! However, the Earth actually pulls the moon towards it with it’s gravity. So the moon is caught in cycle of moving, but it can’t move away from the Earth, and the gravitational pull of the Earth is just enough to keep it at the same distance!
It’s also worth understanding that the Earth has a higher gravitational pull than the Moon because of its larger mass – this is the reason why smaller moons will orbit around larger planets. And in turn, it’s the same reason why the Earth orbits around the Sun – because of that same gravitational pull of a much larger object.
The Earth Moon system is also tidally locked to one another too, meaning that the moon’s surface is always facing us.
All in all, it’s easy to understand that the moon is not actually a planet or a star, but just an astronomical object, or a satellite of the Earth! As I mentioned, the Moon is made up of many different materials like rock and iron, as well as have many different features on its surface.