Universe Sandbox 2 Guide

Universe Sandbox 2 is a physics-based space simulator where you create and destroy planets, stars and galaxies, and the key to using it is understanding two controls: the time step, which sets how fast the simulation runs, and the properties panel, which lets you change any object at any moment. The project by Giant Army began as Universe Sandbox ² and is now sold simply as Universe Sandbox, while the original program is called Universe Sandbox Legacy.

What the Simulation Models

At its core, Universe Sandbox 2 runs an n-body gravity simulation, meaning every object pulls on every other object. Planets orbit stars, moons orbit planets and galaxies pull on each other just as the math predicts. On top of gravity, the newer version also simulates temperature, climate, collisions and the materials objects are made of, which the older Legacy version did not.

The developer keeps some aspects simple so everything runs in real time on a desktop computer. Gravity, for instance, acts instantly in the simulation instead of traveling at the speed of light as it does in reality.

Getting Started With the Built-In Guides

The quickest way to learn the interface is the guides section, found under Home and then Guides. These step-by-step activities walk through the basic features, from placing a planet to watching a collision. Preset simulations, such as the solar system, Saturn with its rings and moons, and the Milky Way, offer ready-made scenes to explore before building your own.

Understanding the Time Step

The time step is the rate at which simulated time passes, for example ten days for every real second. Raising it lets you watch orbits form over years or centuries in a few moments. Lowering it gives more detail for fast events like impacts.

The simulation limits how fast the time step can go while keeping orbits accurate. If you push it too far, the program reduces accuracy or caps the speed, so slow down whenever precise orbits matter.

Changing Any Property at Any Time

Select any object and its properties panel opens. You can change mass, radius, velocity, temperature and composition while the simulation runs. These edits often lead to dramatic results. A well-known example: if the Sun is made massive enough, it immediately collapses into a black hole, and every planet reacts to the new gravity.

Small changes are the best way to learn how the system reacts. Useful experiments for a first session include:

• Doubling the mass of Jupiter and watching how the inner planets respond.
• Removing the Sun and seeing planets drift away in straight lines.
• Adding a second star to the solar system to create a binary system.
• Slowing the Moon until it falls toward Earth.

Materials, Climate and Planetscaping

Objects in Universe Sandbox 2 have a composition made of materials such as rock, water and gases. An update added eight new materials for a total of twelve, usable through the Material and Planetscaping tools or by editing the composition in the properties panel. With these tools you can rain oceans onto a dry world, thicken an atmosphere or terraform a planet.

The climate simulation responds to these changes. Moving Earth closer to the Sun warms it and melts ice, while pushing it further out turns the surface to ice. Watching temperature maps shift is one of the most educational parts of the program.

Collisions and Destruction

Collisions are a favorite activity. When two bodies meet, the simulation breaks them apart into fragments and debris based on their mass and speed. Throwing a planet into another at high velocity creates a cloud of rock, while slow impacts can merge objects. The developer has worked on making impacts and their aftermath more detailed over several updates.

Chart Mode for Comparing Objects

Chart mode arranges all bodies in a simulation and sorts them by values such as mass, size or temperature. It is the easiest way to compare objects side by side, for example to see how Earth measures up against the gas giants. Charts can also be linked to the live simulation, so changes appear instantly.

Learning Through Play

Because it uses real data, real units and real physics, Universe Sandbox 2 doubles as a teaching tool. Classrooms and curious players alike use it to test questions that would be impossible to try in reality. The best approach is simple: pick a question, build a scene, then let the simulation answer.

For a more hands-on kind of simulation, the Turboprop Flight Guide puts you in a cockpit, while the Palworld Starter Guide covers a sandbox focused on survival and crafting.