Portrait of the stars

Space artists play an increasingly important role in imagining distant worlds

(Lynette Cook)The exoplanet HD222582 b as seen from its moon.

CAMBRIDGE - When an exoplanet called 2M1207B was caught in a colossal smash-up earlier this year, the Harvard-Smithsonian Center for Astrophysics summoned David A. Aguilar to recreate the scene.

No way scientists could just snap pictures. The surmised collision with another planet was unfurling 173 light-years from Earth - too distant and too tiny, relatively, for the Hubble Space Telescope or other mighty lenses to catch meaningful images.

The astronomers needed a space artist, and fast: Without a "visual," the spectacular finding, detected through complex gauging of luminosity, temperature, and densities, would be hard to explain to nonscientists.

Aguilar, using computer imaging software, rendered a violent portrait of a blue-green planet smashing into a seething yellow gas giant - an imaginary view, to be sure, but one that fit the available facts, right down to the positioning of wheeling galaxies and cosmic clouds in the background.

It will probably be decades before the next generation of ultra far-seeing telescopes comes on line. Meanwhile, these are salad days for the world's few dozen working space artists - practitioners of a craft that seemed doomed to obsolescence in the 1990s. Aguilar, for example, started creating occasional artwork for the Harvard-Smithsonian in 2002; now, he said, there are weekly calls for illustrations to accompany research.

"This may be our golden age," he said. "Big discoveries are occurring at distances too vast for photographs or at wavelengths that can't be converted into clear, crisp visual images. But there's a hunger for the images to help explain those discoveries."

The images are important to scientists not only to educate the public about their work but to keep enthusiasm stoked among the politicians and big institutions that pay for nearly all such research.

After decades during which Hubble and other orbiting observatories routinely wowed space enthusiasts with calendar-worthy real images of spiral galaxies, supernovas, and nebulas, space artists are filling an unanticipated gap. Using spectroscopes, gamma-ray detectors, and other sophisticated gear, astronomers are probing objects and events deeper in space/time than present-day optical telescopes can decipher in any detail.

"What the space artist does is take raw data - the size of an extra-solar planet, say, or what scientists can deduce about its chemical composition, light emissions, mass, orbital track - and create a plausible picture," said Aguilar, who studied natural sciences at the graduate level and taught himself the basics of illustration as a youth by sketching starfish in tidal pools in his native California. He is the author of two recent books on astronomy - "11 Planets: A New View of the Solar System" was released last month - and his day job is director of public affairs for the Harvard-Smithsonian.

"Partly it's guesswork and imagination," he said of his art in an interview at his Bedford home-studio. "But the visions we produce aren't mere fantasy. They are based on the best science available."

The craft is at least nine centuries old, and probably much older. The famous Chaco Canyon rock paintings left by the vanished Anasazi Indian culture in New Mexico include one petroglyph that is an astronomically correct depiction of the supernova in 1054 that formed the Crab Nebula in the constellation Taurus.

Modern space art started with the late Chesley Bonestell, whose paintings in the 1940s and '50s, appearing in such popular magazines as Life and Collier's, so thrilled Americans - and rocket scientists like Wernher von Braun - they almost embodied the sense of national adventure at the dawn of the space age.

Don't confuse space artists with artful fantasists who depict bug-eyed aliens blasting away with ray guns on lurid planetscapes. That's sci-fi. Space artists apply their talents to science facts - it's an artistic discipline that requires detailed knowledge of astronomy, physics, chemistry, and biology.

"We walk a pretty fine line," said Lynette Cook, a California-based illustrator who possesses degrees in both biology and fine arts, and is widely regarded as the doyenne of 21st-century space artists.

"I want beauty, of course. As an artist, that's what moves me," she said. "But I feel a deeper duty to the science - a duty to depict as much reality as possible. And to make sure that even the imagination parts stay at least within the realm of scientific possibility."

Cook, whose work can be found at lynettecook.com, has illustrated everything from a T. Rex to Civil War battlefields. But her passion is for exoplanets - bodies that orbit stars beyond our own solar system. Since the mid-1990s, she has collaborated with prominent astronomers, including Geoffrey W. Marcy of the University of California at Berkeley, a leading finder of exoplanets.

Said Marcy: "I can tell you that we've discovered a planet with 6.48 Saturn masses and 2.64 times the orbit of the Earth, and provide equations to make your head spin. Lynette can make you feel like you are setting foot on that planet."

Asked whether she fit the bohemian image of an artist, Cook laughed. "Well, probably not too many artists read the Astrophysical Journal. But at least I roll my eyes at the dullest technical stuff."

Harvard-Smithsonian's Aguilar, like most space artists, does most of his "painting" on computer screens, using software that, for example, helps him portray the heavens exactly as they would appear from a moon or star on the far side of the Milky Way. But he also occasionally turns to more old-fashioned materials: He likes to use modeling clay to fashion the peaks, valleys, and cave mouths of other worlds. Aguilar then photographs the shapes and transfers them to his digital canvas.

To make the image of 2M1207B, Aguilar huddled with astrophysicist Eric E. Mamajek, who with colleague Michael Meyer of the University of Arizona had come to the conclusion that the weirdly overheated object detected by infrared imaging was not a single planet, as had been believed since its discovery in 2004. Instead, their analysis pointed to two newly formed planets crashing head-on - much as Earth and a Mars-size object are thought to have collided in the early days of our solar system, blasting off debris that became our moon.

"David asked so many questions about the collision - the size of the planets, their atmospheres, the physics involved, the temperatures," said Mamajek.

NASA and its European counterpart today increasingly turn to space artists as more and more discoveries are based on data for which there is little in the way of direct images - ghostly blobs millions of light years away that may mark the first galaxies forming after the Big Bang; strange but invisible forces contorting space in the region of black holes; or the faint wobble in a distant star that signifies the gravitational tug of an otherwise invisible planet.

"It's art that is peer reviewed," said Robert Hurt, an astronomer who oversees and creates artwork for NASA's Spitzer Space Telescope program. "Nothing goes out without the [senior scientists] on the research signing off on it. A few [scientists] see it as just public relations, but most realize that humans are a visual species. Just as we'll always need science to explain the universe, we'll always need artists to impart the wonder of it all."

Colin Nickerson can be reached at nickerson@globe.com.