Physics · real gravity · drag and throw
Change the planet.
Feel the gravity.
Every ball here falls with a real gravity value, measured in metres per second squared. Switch from Earth to the Moon and they float down six times slower. Jupiter slams them to the floor. Grab one and throw it, and the readout tells you how long a one metre drop takes on that planet.
The physics
Real g, real metres
The floor of the box is 1.6 metres in the simulation, so 1 metre is about 60% of its height. Gravity uses the true surface values: Earth 9.81, Moon 1.62, Mars 3.71, Jupiter 24.79 m/s². A one metre drop takes t = √(2h ÷ g), and the readout uses exactly that.
How it stays smooth
Small steps, every frame
Each frame is split into several small physics steps so fast balls never pass through each other or the walls. Balls push apart along the line between their centres and lose a little energy on every bounce, like real rubber.
Play with it
Grab, throw, switch
Drag any ball and let go to throw it with your hand speed. Tap a planet to change gravity mid-air. Press Shake to toss everything up. Works with mouse, touch and keyboard (1 to 4 pick a planet, Space shakes).