The moon has fascinated humans for ever. Seen from Earth it’s the nearest thing in space and for several years was the topic for the space race. The moon has been around quite a lot longer than human are alive. It’s assumed that the moon has about the same age as Earth, being around 4.5 million years old. The moment our solar system was formed.
First some facts. With a diameter of 3,476 km the moon is about a fourth of the size of Earth. Due to it’s smaller size the moon also has lower gravity than Earth. The moon is primarily made of rock, resulting in having a rather big mass. The estimated mass of the moon is 7.349 x 1022 kg, slightly more than your average American.
The most important distance is that between Earth and the moon, which is 385,000 km. In space understandings that’s nothing. At the speed of a commercial jet it takes about (385,000 km / 1,000 km/h) / 24 h= 16 days. A space rocket is quite some faster, so a four day journey is enough to set foot on the moon.
The sun and the moon appear to be the same size from Earth. The reason is that the sun is both 400 times bigger than the moon and being 400 times further away than the moon. That coincidence also gives us a full solar eclipse.
The exact gravity is 5/6th (or 83,3%) of Earth. Meaning a 75 km person would only have a weight of 12,5 kg on the moon. Also, you could jump about 2 meters hight, if you can jump 30cm on Earth.
You might wonder what the rotation speed of the moon is, since we know all about Earth’s rotation. The answer is simple. The moon doesn’t rotate and can blame Earth for that. It is thought that the moon did rotate for many many years, since it was formed. Earth’s gravity however slowed the moon down till it’s full stop, relative to Earth. That means we always see the same side from the moon and that there is a dark side of the moon as well, that never sees any sun. The moons gravity hasn’t stopped Earth. Yet. Earth is slowing down because of the moon and will reach a full stop eventually. No worries though. You, your kids, grandchildren, their grandchildren and theirs (and many generations after that) will be not around to see that day.
Moons temperature is a lot higher, or lower than Earth, while the distance is so close. There are two main causes for that. Firstly, the moon doesn’t have an atmosphere and air, making the climate less ‘soft’. The second is the lack of rotation making one side very hot when the sun is shining on it and the other side being constantly cold. If the sun is warming up the moon temperatures can go up to 127 degrees celsius, while the dark side of the moon gets as cold as -173 degrees celsius. That’s far, far higher and lower than on Earth.