At what height are you weightless?

When are you actually "weightless"?

• Just lift off the ground weightlessly like the banana in the picture? This will not work because the force of gravity inevitably prevents you from doing it. By the way, this force has nothing to do with the air atmosphere and also nothing to do with the earth's magnetic field. It is a property of masses, in this case the earth and its mass.
• From a physical point of view, you can only be weightless if there is a force that can do it Earth's gravitational pull (also known as gravity or, more generally, gravitational force) both in direction and in terms of its size exactly picks up. How it works can be seen just by being in the water, when the buoyancy compensates for part of the force of gravity.
• On the international space station, for example, this happens through the centrifugal force that you experience as an astronaut when you move on a circular path around the earth. For this purpose, certain conditions apply to the distance and speed of the space station. But even there there is no absolute weightlessness, but what is known as microgravity.
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• Weightlessness on earth or at least in the nearby airspace can be achieved by free fall (Bremen drop tower) or parabolic flights.

Does the height matter?

But couldn't one "escape" the force of gravity at great heights?

• This question is entirely justified, because the earth's gravitational force decreases with altitude. It follows the law of gravitation found by Newton, in which the force decreases inversely with the square of the distance. In other words: at twice the distance, the force of gravity is only a quarter as great.
• Accordingly, there is of course no area in which this force is no longer effective. At a certain height, however, it is very, very small - at least as far as the earth is concerned.
• However, other space conditions also come into play here. Not only does the earth exert an attraction on bodies, but also the moon and the sun. So there is a point between the earth and the moon where the two forces of attraction cancel each other out. Due to the different masses, however, it is much closer to the moon than to the earth.
• There are also two points in the three-body problem sun-earth-moon (Lagrange points), in which spacecraft are weightless because the gravitational forces cancel each other there. And of course there are areas in the vastness of space in which there is so little matter that there is almost weightlessness.

So can you become weightless simply by gaining height? Hardly as a person, even the highest mountains and the usual flight altitudes are not sufficient for this. However, you are a little "lighter" on high mountains.