Explore the Gravity & Orbits Sandbox
Drag planets, set their velocity and watch gravity build orbits, slingshots and collisions. Free, no signup, runs in your browser.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The Gravity & Orbits Sandbox with sample data entered and the result showing.
What is the Gravity & Orbits Sandbox?
Drag planets, set their velocity and watch gravity build orbits, slingshots and collisions. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
Mission planners use gravity assists to send probes to distant planets. Astronomers use the same maths to find exoplanets and to predict where asteroids will go.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Gravity is an inverse-square force: double the distance, a quarter of the pull.
Faster launch speeds make bigger, more elongated orbits.
Small bodies can be flung out by close passes to heavy ones (a gravity slingshot).
Press Add planet and drag from it to set its velocity.
Make a circular orbit by launching at right angles to the star.
Add a moon around a planet.
Used for
Pick one to see how it fits.
Earth & Space learners
Astronomy and earth-science students, and teachers who need a visual model to explain what is happening in the sky.
Try it freeTeachers
For teachers: project the Gravity & Orbits Sandbox on the board, let students predict the result, then run it together and test this: Make a circular orbit by launching at right angles to the star. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
Why do planets stay in orbit?
They are constantly falling toward the star but moving sideways fast enough that they keep missing it.
What is a gravity slingshot?
When a spacecraft passes close to a moving planet, it can steal a little of the planet's orbital energy and leave much faster. Space missions use this to save fuel.
Is the Gravity & Orbits Sandbox free to use?
Yes. The Gravity & Orbits Sandbox is free, needs no signup or download and runs in your web browser. It is part of the Earth & Space group of AZRS simulations.
Does the Gravity & Orbits Sandbox work on a phone or tablet?
Yes. The Gravity & Orbits Sandbox takes touch input as well as mouse input, so you can use its 3 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
How do I use the Gravity & Orbits Sandbox?
1. In the Gravity & Orbits Sandbox, use the controls to change Star mass, New planet mass, Time speed. The simulation reacts instantly. 2. In the Gravity & Orbits Sandbox, pick an option such as Slow, Normal, Fast, Trails to switch modes or load an example. 3. In the Gravity & Orbits Sandbox, press "Pause", "Clear planets" to start, reset or change what is happening. 4. Start with this experiment: Press Add planet and drag from it to set its velocity. Drag any glowing handle, object or slider with your mouse or finger and the Gravity & Orbits Sandbox responds in real time. 5. Change one setting at a time and watch which readout moves, then compare it with this idea: Gravity is an inverse-square force: double the distance, a quarter of the pull.
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Try the Gravity & Orbits Sandbox now
Drag planets, set their velocity and watch gravity build orbits, slingshots and. Free to use.
Try it free