Weight on Other Worlds
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flagWhat you'll discover
- arrow_forwardTell the difference between mass and weight
- arrow_forwardCompare surface gravity (g) across the solar system
- arrow_forwardPredict fall times from different g values
- arrow_forwardCalculate your weight on another world
Mass is not weight
Mass is the amount of matter in you, measured in kilograms. It is the same everywhere in the universe — on Earth, on the Moon, floating in deep space.
Weight is the force gravity exerts on that mass: weight = mass × g, where g is the local gravitational acceleration. Your mass never changes when you travel, but your weight changes on every world, because each world has its own g. On a bathroom scale you are really measuring force, not matter.
Every world has its own g
Earth’s surface gravity is g = 9.8 m/s². The Moon, small and light, manages only 1.6 m/s² — one sixth of Earth — which is why Apollo astronauts bounced like kangaroos in slow motion.
Mars gives you 3.7 m/s², just over a third of home. Giant Jupiter has no surface, but at its cloud tops you would feel about 24.8 m/s², two and a half times Earth. And the Sun? A crushing 274 m/s² — 28 times your normal weight (you would have bigger problems than weight there).
Falling on other worlds
Drop a ball from 10 metres and the fall time depends only on g: time = √(2h ÷ g). On Earth that is 1.4 seconds. On the Moon the same drop takes a dreamy 3.5 seconds; on Jupiter, a snappy 0.9 seconds.
Notice what does NOT matter: the ball’s mass. Heavy and light objects fall together when there is no air resistance — Galileo argued it four centuries ago, and Apollo 15 proved it on the Moon by dropping a hammer and a falcon feather side by side. They landed together.
Do the maths for yourself
Converting your weight is one division and one multiplication: take your Earth weight, divide by 9.8 to get your mass-equivalent, then multiply by the other world’s g. Or simply multiply by the ratio g_world ÷ 9.8.
If you weigh 50 kg-force on Earth, you weigh about 8 on the Moon, 19 on Mars, 126 on Jupiter’s cloud tops, and over 1,400 on the Sun. Set the slider to your own weight in the simulation and tour the solar system’s bathroom scales.