If you’ve ever wondered what would happen if the Sun somehow vanished from the solar system, or wanted to watch planets smash into each other, or thought it would be fun to bombard the Moon with asteroids, you’re in luck! You can do all of those things and more with a computer game called Universe Sandbox2. Dan Dixon, creator of Universe Sandbox2, gave a demonstration of it at this week’s meeting of the Seattle Astronomical Society.
“It is software that allows you to ask fantastical questions about the universe and see plausibly true answers,” Dixon said.
The possibilities are vast. The slogan for Universe Sandbox2 is “create & destroy on an unimaginable scale,” and the software delivers. It lets users tinker with an incredible number of variables, from the mass and density of objects to the chemical makeup of their atmospheres. Eliminate all of the carbon dioxide and see what happens! Move the Moon in closer to Earth and watch the chaos. For all of the interesting science questions it can answer, Universe Sandbox2 also appeals to our inner 12-year-old.
“People like to collide things,” Dixon noted, and clearly he is one of those people.
“It’s a physics simulation, so in addition to doing interesting things with orbits, you can also do interesting things with collisions,” he added.
Those mash-ups got a lot of oohs and aahs from the attendees at the meeting at the University of Washington. It was fun to see what Earth would do to the ring system if it were placed in orbit around Saturn. (Spoiler alert: Disruptive!) Dixon raced through dozens of scenarios, and that only scratched the surface.
He said the results shown in Universe Sandbox2 are “plausibly” true because they have to make some compromises. They don’t simulate every object or every particle out there because that would take way too much computer oomph.
“It’s a very simplistic simulation; we’re not doing any pressure waves or dark matter,” Dixon said, “but it still is pretty cool.”
So when Mars smacks into Earth in an attempt to see if a new moon would result, you don’t necessarily have all of the data you would like.
“You really would want to have like a billion pieces,” Dixon said, but “because we’re trying to do this real time on modern-day desktops or laptops, you can’t have as many pieces as you want and get it still to run in real time.”
“We’re undoubtedly wrong in a lot of cases, and there’s a lot of room for improvement in the simulation,” Dixon noted. They’re revamping the way the program handles stellar evolution and are working to improve planetary climate simulations. Part of the challenge is that they’re often simulating events for which there is not yet a scientific answer.
“We’re trying to solve things that are not well-defined or understood,” Dixon said. That’s not to say they’re just making stuff up.
“Being realistic is really important to me,” Dixon said, but they want to let users come up with their own crazy scenarios. “One of the goals of the software is to allow ridiculous premises but then carry that to a realistic conclusion.”
In a way, Universe Sandbox2 has been in development for 20 years. When Dixon was in middle school his father downloaded a simple gravity simulator from a BBS list. (Remember those?) It didn’t have many features, but it caught Dixon’s interest.
“I’ve always been fascinated with the motions of gravity,” he said, “and gravity is a really simple formula, too. It’s always fascinating how this really simple formula can do these really beautiful and organic interesting motions.” Later on in middle school Dixon coded his own simulator. He’d tinker with it every once in a while, then became serious about it about ten years ago.
“This was not like the grand ambition. It was a thing I was working on for fun, and now it’s turned into this crazy thing,” Dixon said. “What started as a personal side project is now what myself and eight others do full time.”
“I think if I had a time machine and I went back and showed my younger self what it’s become, I would have been overwhelmed and wouldn’t have started on it,” he laughs.
“This is a passion project that I’m fortunate enough to continue working on.”
View the Universe Sandbox2 teaser below. Purchasing through this link supports not only Universe Sandbox2 but also Seattle Astronomy in our efforts to tell interesting stories.