01
Density matters too
Saturn is bigger than Earth but less dense than water — its surface gravity (1.07×) is barely more than Earth's, while much smaller Mercury and much larger Neptune land close together too.
Solar system · Question
How much would you weigh on Mars?
Your mass doesn't change from planet to planet — but your weight does, because weight depends on gravity. Enter your weight once and see it recalculated for every planet.
Visual model
Your weight, everywhere.
on Earth
What's simplified
Why isn't this just "bigger planet, more gravity"?
02
"Surface" is fuzzy on gas giants
Jupiter, Saturn, Uranus, and Neptune have no solid surface — these numbers use the gravity at the visible cloud tops.
Misconception check
Quick check.
Quick check
Go deeper
Keep exploring.
Next in this series →
Planetary temperatures ↗
Why Venus is hotter than Mercury.
Orbits
Why don't planets fall into the Sun?
Gravity's other job: keeping planets in orbit instead of pulling them straight in.
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