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Physics Engineer - Planetary Destruction

Cross-Platform Engineer


General Questions

What is Universe Sandbox?


Universe Sandbox is a physics-based space simulator that allows you to create and destroy on an unimaginable scale while exploring the cosmos. It merges real-time gravity, climate, collision, and physical interactions to reveal the beauty of our universe and the fragility of our planet.


Work on Universe Sandbox began in fall of 2011 and it continues today by a growing team of talented developers, artists, and scientists.

Learn more about Universe Sandbox, or learn more about the team.


Where can I buy it?

Universe Sandbox is now available for Windows, macOS, Linux/SteamOS, HTC Vive, Oculus Rift+Touch, and Windows Mixed Reality.


Buy on our website or via...


Buy on SteamBuy on Humble Store Buy on Buy on itch.ioBuy on Oculus


What does "Early Access" mean?

Universe Sandbox is Early Access software. We have many fixes and improvements planned. You, the Early Access user, will help us uncover bugs and highlight areas for improvement. Buying-in early means you won't have to wait to explore the many new and exciting features that are already in place. Just know that all of the final polish isn't quite there yet.


Learn more on our Steam page.


What platforms does Universe Sandbox run on?

Windows, macOS, Linux/SteamOS, HTC Vive, Oculus Rift+Touch, & Windows Mixed Reality.


See system requirements below.


Is there a demo?

No, we do not have a demo available for Universe Sandbox.


If you buy it directly from us and decide you do not like it, just let us know and we will issue a refund. If you buy it from Steam, you can request a refund within 14 days of purchase and with less than 2 hours of playtime. Learn more about Steam's refund policy


Where can I buy the soundtrack?

The original soundtrack is composed by Macoubre. It is still a work in progress.


We plan to offer the soundtrack for sale separately from Universe Sandbox, but we can't yet say when it'll be available. Sign up for our newsletter to stay in the loop

System Requirements


  • OS: Windows 7 SP1+ (64-bit)* | macOS 10.12+ | Ubuntu 16.04+ or SteamOS‡
  • Processor: 1.6 GHz dual-core
  • Memory: 2 GB RAM
  • Graphics: DirectX 11  (Windows), Metal (macOS), or OpenGL 4.3+ (Linux)
    2 GB Video Memory
  • Storage: 2 GB available space 


  • OS: Windows 10 (64-bit) | macOS 10.12+ | Ubuntu 16.04+ or SteamOS
  • Processor: 3.6 GHz quad-core
  • Memory: 8 GB RAM
  • Graphics: DirectX 12 (Windows), Metal (macOS), or OpenGL 4.3+ (Linux)
    4 GB Video Memory
  • Storage: 2+ GB available space 

Virtual Reality

HTC Vive, Oculus Rift+Touch, and Windows Mixed Reality are officially supported.

For VR system requirements, see recommendations from your headset manufacturer.


* A 64-bit version of Windows is required for Universe Sandbox updates after November 2018 (Update 22). Users on 32-bit systems can still run previous updates. Learn more

† Laptops or other computers that use integrated graphics (rather than dedicated graphics hardware) may have issues with Universe Sandbox even if they meet the video memory requirement. Dedicated video hardware is recommended.

Universe Sandbox officially supports the same Linux distributions supported by our development platform, Unity. Other distributions may work, but would likely require a bit of configuration and tinkering. See our Support page or ask on the forum.

What's New &

What's Planned

What new features are in Universe Sandbox?

Some of the new features include:

  • Climate simulation
  • Advanced collision simulation
  • Dynamic soundtrack & sound effects
  • Stellar evolution & supernovae
  • Terraforming
  • Material & composition simulation
  • Animated star surfaces & solar flares
  • Light-warping black holes
  • Procedurally generated planets, stars, & galaxies
  • VR support for HTC Vive, Oculus Rift+Touch, & Windows Mixed Reality
  • Support for 20+ languages
  • Share & explore simulations on Steam Workshop


How is Universe Sandbox different from Universe Sandbox Legacy?

Short answer:

Universe Sandbox was built from the ground up and is faster, more stable, more intuitive, looks a lot prettier, and simulates more than just gravity. This all makes for a much more enjoyable, interactive, and realistic experience.


Head to our comparison page to see for yourself how different they look.


Long answer:

Universe Sandbox has been built from the ground up in a new game engine, Unity3D. It is more accurate, more stable, and much faster.


Universe Sandbox Legacy was primarily just a gravity simulator, but Universe Sandbox simulates a lot more than just the motion of objects.


Universe Sandbox simulates climate, temperature, stellar evolution, and material composition. It also simulates detailed collisions, which includes cratering, shockwaves, and the explosion of fragments off into space.


It also looks a whole lot better. We now take advantage of some of the latest visual technology to create beautifully detailed stars and planets, glowing craters, supernovas and much more. And the redesigned user interface makes for a much easier and intuitive experience.


Universe Sandbox is also now alive with the sound of music with an original soundtrack composed by Macoubre, and it even has VR support for HTC Vive, Oculus Rift+Touch, and Windows Mixed Reality.


Is there a mobile version?

We're currently working on a mobile version of Universe Sandbox that will be available for phones and tablets. We do not know yet when it will be available.


To receive the latest announcements about the mobile version, sign up for our newsletter


Is there a free version?

We have no plans for releasing a free version.


Does it support other languages beyond English?

Universe Sandbox now supports 20+ languages. See our blog for more information


Can you simulate evolution/life on planets?

We hope to add very basic support for "life." Essentially, given the right conditions — temperature, atmosphere, water, etc. — organics/greenery will appear on planets. Greater complexity may be developed in the future, but it's a long way off.


Is there support for Steam Workshop?

Universe Sandbox currently supports sharing and exploring simulations on Steam Workshop. In the future we hope to support custom textures and models as well.


Are you going to add Steam Achievements?

Yes, this is on our to-do list. Have a good idea for an achievement? Share it on our forum!


How about modding?

Making it easy for the community to create mods is a great idea. We hope to explore supporting mods in the future.

Universe Sandbox

Universe Sandbox includes many guides & tutorials that will take you through the basic features and functions.


In Universe Sandbox, click Home > Guides.


For technical issues, please see our Support page.


Or ask for help on one of our forums: Local Forum | Steam Forum

Simulation Questions

How realistic are the physics in Universe Sandbox?

Unlike many other games and simulators, Universe Sandbox actually simulates gravity, temperature, and climate for various bodies. Many aspects are kept relatively 'simple' in order for it to run in real time on a modern desktop, but we strive to keep the results as realistic as possible.


Gravity in Universe Sandbox is simulated as an n-body problem. An n-body simulation takes small steps forward in time and looks at how each body affects each other body in the system, then moves them accordingly. Read more about this on our blog: Working Through the N-Body Problem in Universe Sandbox.


Alexander, our physics programmer, discusses at length various aspects of the physics implementation on his YouTube channel.


Does it account for relativity?

No, the physics in Universe Sandbox is currently only Newtonian.


Why? The short answer is that you need a supercomputer to accurately simulate general relativity.


Jenn, astrophysicist and Universe Sandbox developer, explains more in a blog post: "General relativity requires simulating the spacetime itself. That is, taking your simulation space, discretizing it to a hi-res 3-D grid and checking the effect that each and every point in that grid has on all neighboring points at every timestep. Instead of simulating N number of bodies, you are simulating a huge number of points. You start with some initial data of the shape of your spacetime and then see how it evolves according to the Einstein equations, which are 10 highly non-linear partial differential equations."


We are, however, interested in adding in a few features which would address some effects of relativity. One example is setting gravity to travel at the speed of light, instead of instantaneously taking effect as it currently does. You can read more about these in Jenn's blog post: Gravitational Waves & Universe Sandbox.


What is "time step" in Universe Sandbox?

As a realistic physics simulator, Universe Sandbox performs calculations in order to advance each frame. It looks at how each object moves in relation to every other object, then calculates where they will be after a certain amount of elapsed time.


This amount of time is the time step.


A simulation running in "real time" would have a time step of one simulated second per one real time second.


An appropriate time step depends on what you are trying to see and what simulation is running. Because of the large scale of the universe, many simulations are better seen at higher time steps. For example, in order to watch the seasons change on Earth, you may want to run your simulation at a time step of one simulated month per one real time second. This means that a simulated year will pass every 12 seconds, making it much easier to observe long-term change.


Why can't I increase the time step as high as I want to?

Short answer: In Universe Sandbox, the time step automatically slows down in order to maintain accuracy. You can adjust this accuracy in Sim > More.


The less accurate it is, the faster it can run, but the likelier it is that errors will add up and orbits will fall apart. In Universe Sandbox, you can learn more in Home > Tutorials > Advanced Time Step Controls.


Long answer: Let's say the time step calls for advancing the simulation one year every frame. Depending on a few factors, this may not be something the simulation can do in a single calculation, while still maintaining accuracy.


But maybe it can maintain enough accuracy if, instead, it takes smaller steps of one month per frame. It then has to make 12 such calculation-heavy steps to advance the whole year. This effectively lowers the time step.


When you increase the time step, you're actually increasing the target time step. This is how fast you are asking the simulation to run. The actual time step, which is shown in the toolbar, will likely not be able to reach this target sooner or later. Its limit is affected by the number of objects being simulated, whether or not there are collisions, and also your hardware.


If you'd prefer speed over accuracy, you can lower the accuracy of the simulation in Sim Settings.


Can you simulate the birth of a planetary system?

No, at least not yet in a way you might expect.


We hope to eventually implement fluid dynamics, which would allow us to model a gas cloud collapsing and spinning up (due to conservation of angular momentum), flattening out into a disk, and condensing into lumps of material, i.e. planets.


For some examples of fluid dynamics using the discretization method called Smoothed Particle Hydrodynamics, check out videos from Alexander, physics programmer for Universe Sandbox.


Until we fully support this, you can approximate the effect by making a large ring system and adding "seed" particles in the form of small moons or planets. This will allow the seeds to accumulate the mass in the ring and grow, while forming gaps in the rings where these seeds attract material.

Legal Questions

Can I create content with Universe Sandbox for use in other products?

Yes, you may use screenshots and video from Universe Sandbox for use in other works/products.


Please see our Usage page for full details.

Other Applications

Are there other programs like Universe Sandbox?

TestTubeGames' Gravity Simulator

  • Fling Planets or redefine the formula for gravity in this easy-to-use 2D simulator.

Pixel Gravity

  • Gravity simulator with both a free trial and full version for Windows PCs.
  • Extremely impressive feature list and comprehensive simulator.

Gravity Simulator

  • An n-body simulator similar in concept to Universe Sandbox and capable of scale simulations of our Solar System.
  • Using the rotating frame feature, you can easily study the complex orbital relationship between the various moons of Saturn, or the relationship between Earth's orbit and the horseshoe orbit of 3753 Cruithne, an asteroid often referred to as "Earth's 2nd moon".
  • It also includes some advanced features for recording data that can be graphed in a spreadsheet app.
  • Gravity Simulator is for Windows PCs.


  • A gravity simulator available for both Mac and Windows as a 15 day trial.
  • Uses Newton's Law of Gravitation to run scale simulations of our Solar System.

Milky Way

  • An astrophysical sandbox game in early development.
  • "Incorporates real observational data and accurate theoretical models to predict various phenomena such as planetary impact, spaghettification and gravitational redshift around a black hole."
  • Free demo available for Windows PCs.




  • Free, realistic space flight and gravity simulation program for Windows PCs.
  • Explore the solar system in realistic and fictional spacecraft.

Kerbal Space Program

  • Build your own rockets, launch them, crash them, land on the moon.
  • Not a full gravity simulator as only one planet or moon acts on the spacecraft at a time, but still really great.


Are there other physics sandboxes?


  • Physics based 2D sandbox (for things here on Earth).
  • Commercial software for Windows and Mac OS X.

Garry's Mod

  • Physics based 3D sandbox (for human sized objects).
  • It's a game Windows and Mac.


  • A simple gravity simulator that's more aesthetic than representative of reality.
  • Runs under Linux, Windows and Mac OS X.


What are some astronomy apps that don't simulate gravity?


  • A space simulator that lets you explore our universe in three dimensions (but it's not interactive and doesn't simulate gravity).
  • All movement in Celestia is seamless and you can zoom from the Earth to the edge of our Galaxy.
  • Celestia runs on Windows, Linux, and Mac.


  • From the creator of Celestia, an easy to use and beautiful solar system visualization tool for Mac OS and iOS.

Eyes on the Solar System

  • Our solar system and NASA mission data.
  • Runs in a browser.
  • Created by JPL & NASA.

Digital Universe

  • A free program from Hayden Planetarium for Windows, Mac, Linux, and IRIX.
  • Includes data on thousands of stars and galaxies.
  • This is not a gravity simulator, only a viewer.

Space Engine

  • Free simulator with both real and procedural content allowing unlimited exploration of our galaxy.


  • 3D space simulation with lots of great visuals.


  • Free planetarium for your computer (not a gravity simulator).
  • Runs under Linux, Windows and Mac OS X.

Explore the Solar System

  • Solar system 3D exploration tool developed in the Unreal 3D engine.


  • Tools for creating sci-fi space maps.


  • An iOS app by Casey Donnellan for iPhone and iPad.
  • Teaches players about the "Goldlocks Zone."
  • Uses a real climate model to determine Earth's average temperature.


What about electrostatic simulations?

Electrostatic Fields Applet

  • Free and easy to use.

Electrostatics 3D

  • Expensive and designed for education specifically.


Atom visualizations?

Atomic Dashboard

  • Chemistry resource and visualization tool.
  • Mac only.

Atom in a Box

  • Easy to use visualization tool for iOS (iPhone & iPad).


And life simulation?

Species: Artificial Life, Real Evolution

  • A realistic evolution simulator.
  • Free alpha versions.

Purchase & Installation

I purchased Universe Sandbox through the Steam Store and need help with my order.

Please contact Steam.


I bought Universe Sandbox from your website. Where is my code?

You should receive an email from Humble Bundle shortly after receiving payment confirmation. This email will link you to a key page with your Steam code.


If you did not receive an email, try using the Humble Bundle key resender:


Make sure it is not being sorted into your spam box.


If you still have not received an email, please contact us.


I clicked on the link in the Humble Bundle email. Now what?

Click the Steam button at the top of your Humble key page to generate your Steam code.


Open the Steam application and log in. Click the "+ ADD A GAME…" button in the bottom left-hand corner. Select "Activate a Product on Steam..." When it asks for a Product Code, enter the Steam code from your Humble key page.


For detailed step-by-step instructions, check out Humble Bundle's support page.


Do I need Steam to install and run Universe Sandbox?

No, you can purchase a standalone version through GOG or These versions do not have any digital rights management (they are “DRM-free”) and can be run without an internet connection or other software. 


With these versions, please note that updates need to be manually downloaded if you choose not to use the store’s software that will handle automatic updates. 


If you previously purchased a copy through TeacherGaming and need assistance, please contact us.


What is Steam?

Steam is a digital distributor and publisher of video games and other software. For developers, it provides an efficient platform for all steps of distribution. It makes it easy to implement anti-piracy tools, connect with users, and release frequent updates.


For players, it makes it easy to access a large catalog of games and organize them in a single spot, as well as receive updates automatically. It is also host to a large and vibrant community of gamers. You can read more about Steam on their site.


How much does Universe Sandbox cost?


  • Instant access to the Early Access version of Universe Sandbox is $29.99 USD.
  • Using screenshots or video from Universe Sandbox for non-commercial use is encouraged. Learn more on our Usage page

Teachers, Schools, & Other Educational Institutions

Commercial & For-Profit Media

  • Instant access to the Early Access version of Universe Sandbox is $29.99 USD.
  • Please see our Usage page for details on using screenshots and video from Universe Sandbox in other works/products. 
  • You may contact sales with any questions.

VR Arcades & Other Public Settings

  • Commercial license subscriptions are available on the Universe Sandbox Store page 
  • In order to see and purchase the commercial license, you will need to join the Steam Site Licensing Program (formerly Cybercafé Program). Learn more 
  • You may contact sales with any questions.


If I buy the Early Access version now do I have to buy Universe Sandbox again when the final version is released?

No, a single purchase gives you instant access to the Early Access version plus a pre-order for the final release. You will receive updates along the way as we continue development.


Will Universe Sandbox become more/less expensive as development continues?

The price will probably increase in the future.


If I bought Universe Sandbox Legacy will I receive Universe Sandbox for free?

No, Universe Sandbox is not just an upgrade, it's a completely new product. You can read more about why in this post.


Universe Sandbox Legacy

When was Universe Sandbox Legacy first released?

Universe Sandbox Legacy was originally released in 2008 with a major update released in 2010.


Read the FAQ about the 2008 and 2010 versions.