Gravity actually determines what the "weight" of an object is. Every object, including you, has a certain mass. If you move that object to a planet with a different gravity, it will "weigh" a different amount because a different amount of gravity will be pulling on it.

If you went to the Moon, you’d weigh less because the Moon only has about one-sixth the gravity of Earth. So if you weighed 60 kilograms on Earth, you’d only weigh 10 kilograms on the Moon. But on Jupiter, which is more massive than the Earth, you would weigh much more-130 kilograms. And in space, far from any celestial objects, you’d weigh practically nothing.
Canadian Heritage Information Network
Australian Museums & Galleries Online, Australia; Centre of the Universe; Gemini Observatory, Hawaii; Glenbow Museum; The Manitoba Museum; National Research Council Canada; Planétarium de Montréal

© Canadian Heritage Information Network, 2003

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