Universe Sandbox: Complete Guide

A hands-on guide to Universe Sandbox: how the simulation works, how to build and break star systems, climate and surface tricks, 30 experiments worth trying, performance tips, and what's new in the Update 36 series.

Researched September 2026 — current as of Update 36.3 "Crashing Craters" (August 2026). Universe Sandbox is still in Early Access and updates often; check the linked sources if something differs.

Quick Start

• It's a physics toy, not a game with goals. There's no win state. You load or build a simulation, change something, and watch real physics play out.
• Start from a built-in simulation. The Solar System and the historical/mission sims (Juno, New Horizons, Artemis II and more) are the best way to learn the interface.
• Time speed is your most important control. Too slow and nothing happens; too fast and the simulation loses accuracy (orbits drift, collisions get missed). Adjust it constantly.
• Select an object, then edit its properties. Mass, radius, velocity, rotation, temperature, composition and more are all editable, and changes take effect live.
• Add objects from the Add menu. Stars, planets, moons, black holes, asteroids, comets, rings, spacecraft, and procedurally generated systems or galaxies.
• Use the tools. Lasers, the collision tools, and the object duplicate button (new in 36.3) let you mess with things directly.
• Share on the Steam Workshop. Save your creations and download thousands of others.
• It's Early Access. The team is mid-way through a multi-year rewrite; expect changes, new features, and sometimes new bugs.

How the Simulation Works

System | What's simulated

Gravity | N-body Newtonian gravity between every object, at almost any speed

Collisions | Objects merge, fragment and leave molten craters; big impacts leave complex craters with a central peak (36.3)

Climate | Surface temperature, sea ice, seasons driven by axial tilt, oceans boiling away near a star

Composition | Twelve materials including water, oxygen and carbon dioxide; compositions can be set by percentage (36.2)

Atmosphere | Geostrophic winds spread gases across atmospheres (36.2); atmospheric drag burns up meteors (36)

Stars | Stellar evolution, flares and prominences, supernovae that leave remnants if massive enough (35.2)

Black holes | Light warping; they now lose mass through Hawking radiation (36.3)

Structure | Object cohesion based on composition, affecting deformation and fragmentation (36.1); objects stretch and deform near tidal locking (36)

What changed in 2025–2026

• Update 35 (March 2025): full graphics overhaul, a new dynamic interface that auto-positions and closes panels, multi-object editing.
• Update 35.2 (June 2025): supernova lighting and remnants.
• Update 36 "Pale Blue DOTS" (March 2026): physics rebuilt on Unity's Data-Oriented Technology Stack (DOTS) for performance; improved lasers that hit multiple objects and can push them with radiation pressure; meteors burning up in atmospheres; stretched and deformed objects.
• Update 36.1 (April 2026): Artemis II simulation and the Orion Integrity spacecraft; cohesion-based deformation.
• Update 36.2 (June 2026): atmospheric winds, shape-hugging selection outlines, composition by percentage, a Rotating Camera that locks to two selected objects, better stellar prominences, 50+ fixes.
• Update 36.3 (August 2026): realistic crater formation and blending, Duplicate objects (button or Ctrl+C / Ctrl+V on Windows, Cmd+C / Cmd+V on Mac), objects fade in and out when added/removed, black hole evaporation, a new exosatellite simulation, graphs that stay open.

Interface Basics

• Home – load simulations, open the Workshop, change settings, and send feedback (Home, then Send Feedback).
• Add – choose an object type or a preset and click to place it. Many objects can be placed with a starting velocity.
• Selecting – click an object to select it. The properties panel shows what you can change.
• Properties tabs – editable settings are grouped (for example, Surface, then Atmosphere, then Geostrophic Wind Speed).
• Tools – lasers and other interaction tools.
• Graphs – plot values like temperature or distance over time. As of 36.3 they stay open and keep their data.
• View options – trails, labels, orbits and grids help you see what's happening.

Tip: the interface auto-manages panels since Update 35, so if a panel vanishes, it was closed to give the simulation room — reopen it from the object's selection.

Time and Accuracy

This is the #1 source of "why did my system explode" confusion.

• Faster time = bigger steps between physics calculations. Close orbits (moons, binary stars) break down at high speeds.
• If orbits drift or objects fly off unexpectedly, slow down time.
• Big simulations with many particles or fragments slow everything down; reduce the number of objects or lower visual settings.
• The DOTS rewrite in Update 36 improves performance and is the foundation for further speed-ups.

Things to Try (Experiments)

Starter experiments

• Move Earth closer to the Sun and watch the oceans boil away and surface temperature spike.
• Change Earth's axial tilt and watch seasons and sea ice change.
• Delete the Sun and see how the planets drift.
• Increase Jupiter's mass until it rivals the Sun, then watch the inner planets destabilize.
• Add a black hole passing through the Solar System.
• Crash the Moon into Earth and look at the molten crater and debris.
• Spin a planet faster until centrifugal force tears it apart.
• Give Earth rings and watch how they behave.
• Laser a ring system — since Update 36 the laser can blast multiple objects at once.
• Collide two stars to trigger a supernova.

Intermediate

• Add enough mass to a star to push it into supernova, then check for a remnant.
• Duplicate the Moon (36.3) and see if Earth can hold two.
• Terraform Mars by adding water and adjusting the atmosphere composition.
• Recreate Titan's atmosphere using the composition-by-percentage editor.
• Adjust wind speed under Surface, Atmosphere, Geostrophic Wind Speed and watch gases spread.
• Run the Meteor Shower sim and watch objects burn up with volatile trails.
• Watch a tiny black hole evaporate from Hawking radiation.
• Select Jupiter and the Sun, then click Rotating Camera to see the Trojan asteroids hold their positions relative to Jupiter.
• Fly along with Artemis II in "Artemis II: Humanity's Farthest Journey" and recreate Earthset.
• Explore the exosatellite sim of the brown dwarf CD-35 2722 b.

Advanced

• Build a stable binary star system with a habitable planet.
• Tidal locking: push a moon closer and watch it deform.
• Roche limit: bring a moon inside a planet's Roche limit and watch it break into a ring.
• Galaxy collision: generate two galaxies and send them at each other.
• Spin up asteroid 2014 RC and see how cohesion (36.1) now keeps it from immediately ripping itself apart.
• Planet formation: scatter a cloud of small rocky objects around a young star and fast-forward to watch collisions merge them into bigger bodies (large particle counts are heavy — start small).
• Meteor bombardment: send a stream of small rocks at a planet and study the crater field (36.3).
• Habitable zone test: move a planet in steps and graph its temperature.
• Remove Jupiter: delete it and watch long-term changes to the asteroid belt and the Trojans.
• Share it: upload your best experiment to the Workshop.

Workshop, VR and Platforms

• Steam Workshop: save and share simulations; browse thousands of community creations.
• Platforms: Windows, macOS and Linux. A VR mode exists; the official support pages point to a Steam Community VR controls guide.
• Preview branch: new features often land first on the !preview-version Steam beta branch — opt in via the game's Properties, then Betas in Steam.
• Mobile: an iOS and Android version is in development per the 2026 roadmap.

Roadmap (as of August 2026)

Actively in development:

• True-shape object collisions with rigid-body physics (basic shapes like cubes and cylinders first)
• Foundational life simulation where life grows, dies and can be eaten
• Surface simulation performance improvements powered by DOTS
• Mobile version

Long-term goals include detailed planet surfaces you can fly over, custom planet maps and images, and building (and destroying) structures from small spacecraft to Dyson spheres.

Common Mistakes to Avoid

• Running time too fast. The most common cause of weird orbits and missed collisions.
• Adding huge numbers of particles and wondering why frame rate collapses.
• Forgetting to save before a destructive experiment. Save a copy first so you can reload.
• Editing the wrong object. Check the selection outline (now shape-accurate since 36.2) before changing mass.
• Expecting surface details to copy. Duplicated objects don't yet copy detailed surface data; liquids and temperature spread evenly and may need time to settle (36.3).
• Using Legacy guides. "Universe Sandbox Legacy" is the old 2008 game; its keyboard reference doesn't apply to the current version.

Advanced Tips

• Graph everything. Graphs turn a pretty visual into a real experiment — track temperature, distance, or velocity over time.
• Use the Rotating Camera for any co-orbital or resonant system.
• Change one variable at a time. Duplicate a system (or save copies) and change just mass, or just tilt, to see the effect clearly.
• Reverse-engineer Workshop sims. Open popular Workshop creations and inspect object properties to learn setups.
• Send feedback in-game (Home, then Send Feedback) if you find bugs; the team fixes a lot between updates.
• Try the preview branch if you want new physics early, but back up saves first.

FAQ

Is Universe Sandbox scientifically accurate? Gravity is real Newtonian N-body physics, and many other systems (climate, composition, stellar evolution) are modeled approximately. It's great for intuition and education, but it's not a research tool.

Is Universe Sandbox the same as Universe Sandbox 2? Yes. The remake was renamed "Universe Sandbox" in December 2018, and the original became "Universe Sandbox Legacy."

Why do my orbits break? Time is running too fast for the simulation's step size. Slow down.

Is there VR support? Yes, VR is supported; see the Steam Community VR controls guide linked from the official support pages.

Will it leave Early Access? There's no announced date. The team is doing a multi-year, piece-by-piece rewrite (graphics in 2025, physics in 2026), with life simulation, rigid-body collisions and mobile in progress.

How do I duplicate an object? Select it and click Duplicate, or use Ctrl+C then Ctrl+V (Cmd on Mac). Added in Update 36.3.

Is there a sale? It usually goes on sale around the Early Access anniversary each August; the 11-year anniversary sale ran through August 31, 2026.

Sources

• Universe Sandbox on Steam
• Universe Sandbox Steam news (Updates 36 to 36.3, 2026 roadmap, anniversary)
• Universe Sandbox support
• Universe Sandbox on Wikipedia