By Published: Dec. 7, 2021

Banner image: A glass block marks Saturn's spot in the solar system in a new scale model on the CU Boulder campus. (Credit: CU Boulder)

Have you ever wanted to travel to Neptune? Thanks to an updated solar system model on campus, you can “visit” the planet as you stroll from the Fiske Planetarium north to Colorado Avenue—just a few minutes if you hustle. You can also catch the sounds of Neptune and other planets and asteroids as they go whooshing by on your smartphone.

This week, Fiske Planetarium and Sommers-Bausch Observatory is unveiling the next generation of the Colorado Scale Model Solar System, plus an associated smartphone app that sets out to “sonify” Earth’s cosmic neighborhood.

The model solar system, which has delighted campus visitors since 1987, squishes space down by about 10 billion times. Earth, which has a diameter of 7,917 miles, is now roughly the size of a pepper grain. You start off near the planetarium where a grapefruit-sized sphere represents the sun, then walk for about a third of a mile, passing exhibits for all eight planets on the way.

Graduate student James Negus helped bring the new model to campus. It’s based on a model developed by the National Center for Earth and Space Science Education called the Voyage Mark II. The installation shows visitors just how big space is, filled with vast distances that are hard for textbooks to capture. CU Boulder faculty members John Keller and Seth Hornstein helped Negus make it all a reality.

“As humans venture farther and farther into the universe, these types of distances are going to be so important to understand,” said Negus of the Department of Astrophysical and Planetary Sciences. “At the scale of the new model, to get to Proxima Centauri, the star nearest to our solar system, you’d have to travel from Boulder to the Panama Canal.”

Chancellor Philip DiStefano and other campus dignitaries will usher in the cosmic experience at a ribbon-cutting event at 4:30 p.m. on Wednesday, Dec. 8. CU Boulder is the first institution in the world to install a Voyage Mark II model, and the Fiske team hopes other universities will follow suit.

For the first time, space buffs can supplement that experience by downloading an iPhone app called Wanderers. The app allows users anywhere on campus to hear the planets as they move through space, transforming campus into a sometimes-eerie symphony. Artist and designer Teri Rueb led the team that developed Wanderers.

If you go

Who: Open to the public
What: Ribbon-cutting featuring Chancellor Philip DiStefano and others
When: Wednesday, Dec. 8, 4:30 p.m.
Where: Outside Fiske Planetarium

“You can feel the relative distances between objects in the solar system as you move through campus, and you’re no longer tied solely to these physical exhibits,” said Rueb, chair of the Department of Critical Media Practices in the College of Media, Communication and Information.

From clay to glass

That immersive experience got its start in the early 1980s. Jeffrey Bennett, then a graduate student in astrophysics at CU Boulder, was teaching science to elementary school students in San Diego. In one exercise, he asked them to roll up balls of clay to represent the planets, then pace out how far apart they should be on the school playground.

From left to right, Lorna Onizuka, widow of Ellison Onizuka, CU Boulder Chancellor James Corbridge and CU System President E. Gordon Gee attend the unveiling of the original Colorado Scale Model Solar System in 1987. Tom Ayres, left, a senior research associate at the Center for Astrophysics and Space Astronomy (CASA) at CU Boulder, helps to lift the central pyramid for the model solar system into place in 1987.

Top: From left to right, Lorna Onizuka, widow of Ellison Onizuka, CU Boulder Chancellor James Corbridge and CU President E. Gordon Gee attend the unveiling of the original Colorado Scale Model Solar System in 1987; bottom: Tom Ayres, left, a senior research associate at the Center for Astrophysics and Space Astronomy (CASA) at CU Boulder, helps to lift the central pyramid for the model solar system into place in 1987. (Courtesy of Jeffrey Bennett)

“I realized there were a lot of misconceptions, even among college students, about the scale of our solar system,” said Bennett, who runs a company called Big Kid Science from his home in Boulder. “You see those NASA photos and they make you think the planets are close together.”

They’re not. Earth, for example, sits relatively snug to the sun at an average distance of about 93 million miles. Neptune, however, orbits more than 30 times farther away.

The solar system model captures these distances with educational signs rather than small balls of clay. After the Challenger disaster of 1986, it also became a memorial for alumnus Ellison Onizuka and other astronauts who died on that space shuttle. The new model will also include a memorial for astronauts who died aboard the Space Shuttle Columbia in 2003, including alumna Kalpana Chawla.

Thirty-five years of Boulder weather have taken their toll on the installation, so Negus and others across campus hit the pavement to raise funds for a new one. Among other changes, the Voyage Mark II model displays the planets in glass blocks with laser etchings.

“When kids come and see the model, their eyes brighten,” Negus said. “They can actually see that it takes them about 20 steps to go from the sun to Earth, but then 100 steps to go from the sun to Jupiter, and they say, ‘Whoa.’”

And, yes, Pluto will still make an appearance in the new model but it will be labeled a dwarf planet this time around.

“The new solar system model represents a rich collaboration between Fiske, Sommers-Bausch Observatory, Critical Media Practices and others,” said Keller, director of the planetarium. “We are grateful for the support provided by CU Grand Challenge, Jeff Bennett and Big Kid Science, the Laboratory for Atmospheric and Space Physics, the Chancellor’s Office, Aerospace Engineering, Astrophysical and Planetary Sciences and other private donors.”

Sonifying the solar system

The Wanderers app, meanwhile, gives visitors who are blind or have visual impairments a chance to experience the solar system, too. The app team includes critical media practices graduate student Roberto Azaretto and alumnus Jiffer Harriman.

Within the app, users can watch the planets sweep through campus at exaggerated speeds (by default, one Earth year equals 10 seconds). If you get close enough to those behemoths, you can also hear them boom and hum through your headphones. Azaretto, a composer, gave each orb its own signature sound by tweaking a common 9-note chord.

“Jupiter—being by far the biggest planet—has the lowest frequency, and Pluto has the highest,” he said. 

You can download the app to your iPhone now, and an Android version will be available in the next few months.

Bennett views the model and app as a chance for people to understand their place in the universe—a down-to-Earth way to experience a bit of the same awe that astronauts in space feel when they first see the curve of the planet below them.

“You may get the same sense looking at that tiny little Earth in a piece of glass on campus,” Bennett said. “That’s it. That’s us. We all have to share this one tiny world.”