When Jon Lomberg worked with Carl Sagan on illustrations for "Cosmos," the late scientist's landmark book and 1980 television series, they chose an airborne dandelion seed to "launch a spaceship of the imagination."

For years, the link between botany and astronomy lingered in Lomberg's mind: "The lives of stars, plants and humans is a pattern that keeps on repeating itself," said Lomberg, who wanted to give people a sense of where our solar system is in the galaxy.

"I thought about building a walk-through galaxy for a science museum, but then a lightbulb went on and I envisioned the project as a garden instead — a live garden representing the living universe that people could explore themselves."

Lomberg's idea eventually took seed and his "Galaxy Garden" at Paleaku Peace Gardens Sanctuary in Kona opened this month to the public. The 100-foot-diameter garden is an outdoor scale model of the Milky Way's spiral galaxy, mapped in plants and flowers and based on current astrophysical data.

"The hardest thing to envision about the galaxy is its sheer vastness," the artist said. " ... A large garden seemed to offer better ways to suggest our place in the universe."

To Lomberg, the Big Island was the obvious place for such a project; the island's Mauna Kea Observatory is home to the world's most powerful telescopes. When he described his idea for the garden to Paleaku Peace Gardens Sanctuary director Barbara DeFranco, she immediately offered him the site to build it. Community volunteers turned up for Sunday afternoon work sessions and Konawaena High School students came weekly to help build and plant the galaxy while learning about it.

"Students are the most important visitors to the garden, and we need a galactic perspective for the 21st century," Lomberg said. That galactic perspective — conveying the size and relationship of celestial bodies to each other — became the garden's mission.

Until you walk in the garden, Lomberg said, you don't really understand your place in the galaxy.

"Everything in space is so big. Even the distance to the moon is huge, and that is the shortest distance to consider. The garden offers a way to understand these distance and size relationships. When people later look at the real Milky Way, they can understand what they are seeing."

Lomberg grew up in Philadelphia but after one short visit to Hawai'i, he decided to move to the Big Island in 1987. "The overwhelming beauty of land, sea and sky were irresistible," he said.

And the astronomy, a powerful lasting inspiration for Lomberg's extensive work in film, TV, print, computer graphics and museum exhibits. His large, accurate painting of the Milky Way galaxy was displayed for 10 years at the Smithsonian Institution's National Air and Space Museum and is now part of their permanent collection of aviation and space art. He's currently designing exhibits for the Mauna Kea Astronomy Education Center under construction in Hilo.

It's not all Earth-based. Lomberg's design for a sundial decorated with the names of Mars in many languages, including in Hawaiian "Hoku'ula," will be aboard NASA's Mars Science Laboratory mission, planned for launch in fall 2009; his sixth object to fly to deep space.

Meanwhile, he said the Galaxy Garden will keep on expanding. "We'll continue working on it, improving it, mapping additional celestial objects into the design, lighting it up at night, and developing student activities."

Reach Chris Oliver at coliver@honoluluadvertiser.com.