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Why do things float around in space?’
This is down to motion; satellites are not stationary. In a roller coaster, during the fast descent phase, you may feel that you weigh virtually nothing and you begin to feel you could float out it you were not strapped in. This is a real effect. The vehicle you are in is rapidly descending and so are you. Gravity is doing its job just the same and yet you feel lighter. If you could weigh yourself at this point, you really would have been on an instant diet, kilograms have vanished. Once you reach the bottom of the ride, full weight is resumed; sorry, (unless you have thrown up). The description that is more accurate should be 'Weightlessness' rather than Zero Gravity; it's simply too confusing.
An orbit is achieved by basically throwing an object so fast forward that as the earth's gravity tries to pull it back down, it can't. The object just flies around constantly missing the earth's curvature.