The planet Earth that we live on spins constantly, with a speed of roughly 460 meters per second. We walk on it, we built houses on it, we drive vehicles on it, … The earth doesn’t have a roof or anything though that makes it seem like there is a border around it. We can’t physically feel a force that is pulling us towards the ground at all times but we can still be on the planet freely without falling off of it. How is that possible? How can we live on something that doesn’t have a visible roof, where there’s no borders or anything?
If one of these questions has ever crossed your mind and you wondered about the how and the why, this article is perfect for you.
You have all probably heard of the force of gravity before. To simply put it, this is what keeps us from falling off the Earth. The definition of it is: “Gravity is the force by which a planet or other body draws objects towards its center.” It means that this strong force pulls us towards the middle of the Earth, explaining why we are still standing on this planet. It also keeps all of the planets in orbit around the sun which is necessary for us so that we don’t get too close or too far away from the sun.
The same goes for objects that fall down on the ground when you throw them in the air. You might haven’t thought about it that much but it is kind of weird that when we jump or throw something in the air, we/ the objects don’t go floating in space. Instead, we land back on the ground, so you could say that gravity is pretty much what makes things fall. We also exert the same gravitational force on the Earth than it does on us but because it has so much more mass than we do, our force doesn’t really have an effect on the planet.
The force of gravity is also the phenomenon behind the well-known black holes. In a black hole, gravity is so strong that it can keep anything, even light, from escaping, thanks to the huge amount of mass that is packed into such a small volume.
I also mentioned earlier that the Earth moves at a speed of approximately 460 meters per seconds. Even though this is incredibly fast, we don’t see or feel any movement because, held firmly by gravity, the things around us move with us in exactly the same way.
Well, I guess we do see the movement in one area, the sky. Everyone loves watching a sunrise/ sunset and it would be nice to watch it multiple times a day but because the Earth spins around on its axis once a day, it takes her a whole day, 24 hours, to pass the sun again. Since for us, it looks like the sun is moving throughout the day from east to west, it is easy to forget that we are actually the ones spinning around the sun, and not the other way around, which is what people used to believe for a long time.
However, lucky for you, you now won’t be one of those people. Every time you drop something or you watch the sun in the sky, you know what phenomenon is responsible for all of that: the force of gravity.
Sources:
https://www.scientificamerican.com/article/how-fast-is-the-earth-mov/ (Scientific American, October 19th, 2022)
https://theconversation.com/curious-kids-if-the-earth-is-spinning-all-the-time-why-dont-things-move-around-150909 (Jacco van Loon, October 19th, 2022)
https://spaceplace.nasa.gov/what-is-gravity/en/ (Space Place, October 19th, 2022)