The Man Who Built the Universe

Ever wondered what would happen if a rogue planet smashed into Earth? Or what would go down if Neptune magically teleported over to Saturn? Or, on an even bigger scale, what the Milky Way and Andromeda will look like when they inevitably collide in four billion years?

If you are the sort of person who likes to indulge these types of cosmic hypotheticals, then Universe Sandbox—a comprehensive space and gravity simulator—is right up your astronomical alley.

Depending on your predilections, you can use the simulator to create entirely new alien worlds, or destroy the familiar planets of our own solar system. You can explore hundreds of real stars in our Sun's vicinity, and dozens of galaxies neighboring the Milky Way. You can even sit back and watch as galaxies collide, asteroids are launched, and supermassive stars are born. Awesome.

Indeed, in much the same way that Kerbal Space Program has allowed space enthusiasts to experiment with real rocketry concepts, Universe Sandbox has introduced its users to the elegant world of Newtonian physics, with startling accuracy and beautiful graphics.

The simulator is very much a labor of love, and was first developed by the versatile programmer and artist Dan Dixon. Dixon launched the first incarnation of Universe Sandbox in 2008, then issued a major update in 2010. The encouraging response prompted him to go all in on the project, and in 2011, he founded the company Giant Army.

Since then, he has recruited a diverse team of specialists, including an astronomer and a climate scientist, to build an even more expansive version of the simulator—Universe Sandbox².

I spoke to Dixon about the origins and development of this rapidly evolving project, and what Giant Army has planned for the next incarnation. Needless to say, space enthusiasts are in for a treat.

Motherboard: What was the initial inspiration for Universe Sandbox?

My dad showed me a simple gravity simulator when I was in middle school and I fell in love with the motions of the orbits, but I was disappointed with the lack of options. A few years later, in high school, I spent a few weeks making a simple gravity simulator, and kept coming back to the idea every five years and working on it for a week or two.

The last time I started working on it back in 2007, I never stopped.

How did the concept evolve as you worked on it?

Universe Sandbox started as a personal project just for fun, there was never a grand plan to make what it has become. I'd often sit down each day and work on whatever new feature seemed interesting at the time. The original Universe Sandbox, what we're now calling Universe Sandbox Legacy, developed over a slow iterative process from 2008 to 2011.

At first it was just random unitless spheres (mass = 5, radius = 2), but eventually I moved everything to real units and scales (mass = 6*10^26 kg, radius = 5,600 km) and continued iterating from there. As examples: One day I decided to make the bodies selectable, and the next I'd add a menu to allow the user to change the properties as it's running; I'd add different color modes, or work on improving the drawing of the trails.

After Universe Sandbox Legacy released on Steam in April 2011, it sold better than I ever imagined and decided to hire a couple guys I had only met over the internet to help me rewrite Universe Sandbox and make it as awesome as I imagined it could be (and it's turned out even more awesome than that).

How has the process changed in the last few years since founding Giant Army? I was reading up on the team and there is definitely an "Avengers Assemble" vibe given all the diverse backgrounds. What's it like working with such an interdisciplinary group?

I love working with people smarter than me and have been adding a new team member or two a year since 2011. While I wrote the first one by myself I was at the extent of my capabilities so it's so great to have a diverse team that makes things possible that I hadn't even imagined. It's been interesting working with scientists (who don't have a background in games) and game developers who each bring a different personal priority to the project. I love the balance and conversations this produces.

As an aside, the name of the company, Giant Army, is inspired by the phrase "standing on the shoulders of giants."

What are the most popular activities on Universe Sandbox? What do users seem to get the biggest kick out of—building solar systems, colliding galaxies, or something else entirely?

It seems the popular activities are pretty diverse. Some people love meticulously building their own solar system, planet by planet, moon by moon, while others love a more chaotic experience launching a flurry of 100 moons at a planet to unleash amazing, but beautiful devastation.

What are your own favorite activities within the simulator?

I've probably collided the moon into the Earth over 1,000 times. It just never gets old, and with improvements still to come, it's going to look and work even better.

I also love dropping Neptune next to Saturn and ripping apart its rings in the most amazing way possible.

What is Giant Army working on at the moment?

We've been working on Universe Sandbox², the sequel, since late 2011. It's already available for sale on our website in its early alpha state, and we'll be launching it on Steam Early Access later this summer, at which point we will continue to release updates and improvements for the foreseeable future.

In just the last two months, we've been working on a major overhaul of the user interface (UI) and have nearly rewritten our custom physics library to make it more than twice as fast. We've got a ton of more features in the works:

• new system for point based temperature and liquid flow/depth calculations on planets, which allows a slowly rotating planet to be molten on its light side and cool on the dark side, or liquids to spread out across a planet's surface.
• composition improvements which will consider pressure as well as temperature, allowing for crazy experimentation like increasing the atmospheric pressure on Mars (by a factor of 200x) and creating liquid oceans of carbon dioxide.
• tether system that will allow the user to simulate the real physics behind a space elevator.

Even though it's been 8+ years (and almost four on the sequel), I'm more excited about this project than ever. We're making something that's never been made before and we've finally got a really great foundation to continue to iterate and build upon. Universe Sandbox² just keeps getting more and more awesome.

Perfect Worlds is a series on Motherboard about simulations, imitations, and models. Follow along here.