Just about all subjects fit into realm of scientist William K. Hartmann — from astronomy and natural-lands studies to Spanish history.

William K. Hartmann sees the big picture.

Talk to him about his varied interests - Spanish conquistadors, space artist Chesley Bonestell, archaeology, the environment - and you'll see. Hartmann has a detailed understanding of each one, but also understands its larger purpose.

His studio reflects his big-picture style: Colorful stripes of CD and book covers on shelves, countertops covered in paint tubes and bottles, computer equipment, canvases of spacecraft, cities and flowers. It's music, art, literature and science, all together in one place. His studio is directly behind his home, as if to say Hartmann and his work are never far apart.

But if you ask him about himself, you'll likely learn about something that's fascinating him instead.

Though Hartmann may be modest, his achievements are not. He's the 2010 winner of the Barringer Medal, an international award given by the Meteoritical Society to those who've done exceptional research on impact craters. But the award is only a tiny piece of the big picture that makes up the leading researcher's important contributions.

Hartmann is the main author of the leading theory about the moon's origin - a question scientists have tried to answer for centuries. His hypothesis has held up to scientific scrutiny since its publication in 1975.

The theory suggests the moon is actually made of debris blown off the Earth's rocky surface by a giant impact during Earth's formation, rather than forming elsewhere in the solar system and being pulled into Earth's orbit.

Additionally, Hartmann is a founding member of the Planetary Science Institute, a local, nonprofit research group, where he continues to work as a senior scientist.

Hartmann's career highlights are as diverse as his interests: major achievements in planetary science, five illustrated books on astronomy, three college textbooks and two novels, as well as his well-known work as a space artist.

Hartmann, 71, was born in New Kensington, Pa., and had many interests from the start. His childhood love was archaeology, but astronomy began to pique his interest as he flipped through the pages of Bonestell's 1949 book, "Conquest of Space," which examined space exploration through paintings.

Hartmann's grandfather was an artist and he was encouraged to paint, he said. But instead of "an existential crisis" about whether to pursue science or art, Hartmann did something unconventional: He chose both.

He briefly put down his paintbrush to complete a physics degree from Pennsylvania State University. He went on to finish a master's in geology and a Ph.D. in astronomy from the University of Arizona.

Hartmann and friend Dale Cruikshank met in 1961 as graduate students working under Gerard Kuiper in the early days of the UA's Lunar and Planetary Laboratory.

Cruikshank, now a research scientist at the NASA Ames Research Center, described Hartmann as easygoing and a creative thinker. He said Hartmann is able to fit tiny details that frustrate others into a larger context that answers big questions.

"It's exactly how he and [Donald R. Davis] came up with their theory on the origin of the moon," Cruikshank said.

Hartmann's interest in the moon was unusual for the time, when most astronomers were interested in stars and galaxies. The moon was aggravating, like a bright street lamp interfering with astronomers' work, Hartmann said.

However, he was more fascinated than annoyed by the moon.

"I knew the moon was a place, not just a thing in the sky," he said. "It was real, and all you had to do was go there."

Hartmann's art is regularly linked to his scientific work in what he described as "pictorial thinking."

"The best space artists talk to scientists and try to understand, try to synthesize what it would be like to be there," he said. Imagining stories about space forces one to deal with questions that aren't often asked, he said.

Hartmann's paintings have been exhibited at the Smithsonian National Air and Space Museum in Washington, D.C., among other places.

"His artwork is highly respected based on the best scientific evidence available as to how a planet, a landscape on Mars would look," Cruikshank said. "It's not just cartooning. It's carefully thought through. The colors, the lighting are correct as best we know."

If Hartmann's significant scientific and artistic achievements weren't enough, he can add family to that list: Gayle, his wife, is known for her work on regional land-use issues and was a leader in the historical re-creation of the downtown Presidio San Agustín del Tucson, Hartmann said. She is now president of Save the Scenic Santa Ritas. They have one daughter, Amy.

Despite so many successes, Hartmann isn't ready to slow down. He recalled being 10, listening to his parents talk about retirement. When he expressed his interest in the concept, he said his father - a civil engineer at Alcoa Aluminum - pulled him aside.

"He said, 'You're never going to retire.' I think what he meant was that I was interested in so many different things," he said. Modestly, he gave a simple explanation for his desire to continue working.

"I think it's good to pursue the things you're interested in."

Contact NASA Space Grant intern Victoria Blute at vblute@azstarnet.com