Gravity Sandbox
Fling planets into orbit and watch them dance, collide and form systems. Mesmerizing.
Drag anywhere to fling a planet
Aim & pull back for power · they'll find each other
…or load a preset below
Physics
Look & feel
Tips
- · Drag slow & sideways for clean orbits.
- · Tiny bodies orbit massive ones — make a sun first.
- · Heavier bodies glow warmer.
- · Collisions merge & conserve momentum.
Why you’ll love Gravity Sandbox
Instant & free
No signup, no paywall, no limits — Gravity Sandbox works the moment the page loads.
Completely private
Everything runs in your browser. Nothing you enter is ever uploaded or stored on a server.
Works on any device
Fully responsive and touch-friendly — use it on your phone, tablet or desktop.
Endlessly playable
Designed to make you lose track of time — and come back for more.
How to use it
Open it
No download and no login — the tool is ready right at the top of this page.
Use it
Enter your details or start interacting. Everything updates live as you go.
Get your result
Copy, download or share your result in a single tap. That’s it.
About Gravity Sandbox
Gravity Sandbox is a free, browser-based orbit simulator that lets you create and manipulate planetary systems in real time. Fling planets into the void and watch them respond to gravitational forces, forming stable orbits, chaotic dances, or spectacular collisions. This n-body simulation runs entirely in your browser—no installation, no signup, no data collection. It's a surprisingly engaging way to explore how gravity shapes the cosmos.
Unlike static diagrams in textbooks, this gravity simulator shows gravitational interaction unfolding in real time. Watch as planets attract each other, swing around in complex elliptical paths, and sometimes merge into new bodies when they collide. The n-body simulation engine handles all the physics calculations quietly in the background, leaving you free to create and experiment. It's remarkably meditative—unpredictable, compelling, and genuinely mesmerizing to watch evolve.
Built for curiosity, not complexity. You don't need a physics degree to enjoy an orbit sandbox—just the impulse to create and experiment. Fling objects, adjust their starting velocities, and observe how tiny changes cascade into wildly different outcomes. Every session is free and runs entirely on your device.
Popular uses
Frequently asked questions
An n-body simulation calculates how many objects (the 'n' bodies) move under mutual gravitational attraction. Instead of assuming planets orbit a fixed star, this gravity simulator treats every object as pulling on every other object, creating far more realistic and unpredictable behavior. Collisions, orbital decay, and system breakups all emerge naturally from the physics.
Yes, within limits. You'll develop intuition about how gravity works—why orbits are elliptical, how velocity and distance interact, what happens when objects get too close. It's not a textbook, but watching cause and effect in real time often makes concepts stick better than reading about them. It's a useful supplement to formal learning, not a replacement.
When two objects collide in the orbit sandbox, they merge into a new body. The simulation conserves momentum and mass—the new planet inherits the combined mass and moves according to the collision physics. It's one of the most dramatic moments to watch.
Yes. Gravity Sandbox runs in any modern web browser on desktop, tablet, or phone. It requires no installation, signup, or downloads. Everything runs on your device itself—your creations never leave your screen, and the tool works offline once loaded.
Gravity Sandbox is 100% free — no signup, no watermarks and no usage limits. It’s one of 200+ free tools we build and give away.
Never. Just open it and play — no signup, no installs, nothing to lose.
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