Answer ( 1 )

  1. This is a very common misconception. There is absolutely gravity in space. The ISS is in orbit at about 350 km above the surface of the earth. And they DEPEND on the gravity. The orbit would not work if it weren’t for gravity. Let me explain why.

    Perhaps you have heard the term “free fall” associated with something in orbit. That’s because the object in orbit (satellite, ISS, space shuttle, etc) is in free fall. If something is resting on something else, it is not in free fall. Everything else is in free fall. If you throw a ball in the air, it is in free fall from the time it leaves your hand. Birds and planes in flight are not weightless because they are “resting” or supported by the air that they are flying in. And things that are in free fall are considered weightless. You are not weightless right now because you are sitting in your chair. So, the ISS is falling because it is not being supported by anything. And what makes things fall? Gravity. And since the ISS is falling, and the astronauts are falling along with the ISS, they are also weightless.

    You might wonder then why doesn’t the ISS come crashing down to earth, since it is in free fall after all. The reason why it doesn’t hit the earth is because it keeps on missing. You see, it is travelling so fast sideways (17,500 mph) that as it falls, it follows along the curvature of the earth exactly.

    Let me give you one more thought experiment. Imagine a pole that is big enough for you to stand on, three meters high. You can stand on it, and you don’t feel any lighter because you are only ten feet high. If you jump off, you know you will land on the ground. That’s gravity at work. Now imagine the pole 350km high. And you are standing on the top of it. Yes, you would be able to stand on it. You’ll need a space suit because there is no air up that high. But you would not be weightless. Not by a long shot. You would be a little lighter due to centripetal forces and the fact that you are 350km above the surface of the earth. But you would be able to stand just fine. And if you can stand, that means you can jump. You would fall off and start rapidly accelerating to the earth’s surface. And why would you fall? Because of gravity. Even that high.

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