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Gravity Sandbox

Fling planets into orbit and watch them dance, collide and form systems. Mesmerizing.

  • 🌀 Toy
  • ✓ Free
  • ✓ No sign-up
  • ✓ Private — runs in your browser
  • ✓ Any device
Power
🪐

Drag anywhere to fling a planet

Aim & pull back for power · they'll find each other

…or load a preset below

Physics

Gravity
Sim speed
New body mass

Look & feel

Trail length

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 & freeNo signup, no paywall, no limits — Gravity Sandbox works the moment the page loads.
Completely privateEverything runs in your browser. Nothing you enter is ever uploaded or stored on a server.
Works on any deviceFully responsive and touch-friendly — use it on your phone, tablet or desktop.
Endlessly playableDesigned to make you lose track of time — and come back for more.

How to use it

  1. 01

    Open it

    No download and no login — the tool is ready right at the top of this page.

  2. 02

    Use it

    Enter your details or start interacting. Everything updates live as you go.

  3. 03

    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

  • ✦ Exploring how gravity creates stable orbits and what small changes lead to system collapse
  • ✦ Learning orbital mechanics intuitively before (or instead of) diving into the math
  • ✦ Creating mesmerizing planetary systems and watching them evolve over time
  • ✦ Understanding n-body problems through direct observation and experimentation
  • ✦ Pure relaxation—watching planets drift, orbit, and interact with zero pressure or goals

Frequently asked questions

What exactly is an n-body simulation?
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.
Can I actually learn physics from this?
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.
What happens when planets collide?
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.
Does it work on my device?
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.
Is Gravity Sandbox free to use?
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.
Do I need an account to play?
Never. Just open it and play — no signup, no installs, nothing to lose.

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