American Scientist

Cosmic Art

If the role of art is to extend our senses and our experiences into the realm of the unknown and the unfamiliar, to imbue us with a sense of awe and wonder at the glory and grandeur of nature, and to push the boundaries of what we know and feel, then deep space exploration has provided some of the most spectacular and humbling kinds of art that humans have ever produced.

The images included here are from the farthest reaches of our Solar System, where humans have never traveled: Uranus, Neptune, and Pluto. Although the photos were taken by uncrewed space probes, robots did not produce the art; people did. Robotic missions and instruments are built by and operated by virtual explorers back here on Earth, who get to plan and compose the photos, choose the timing and the framing, set the exposures, and digitally process the images afterward. These images celebrate the scientists and engineers who push human civilization—including the ways in which we produce and experience art—beyond the physical limits of our planet.

Uranus and the Epsilon Ring

Digital (non-film) space photography dates back to the use of 1950s-era vidicon cathode ray tube technology that was first developed for television broadcasts. By today’s standards, the images taken by such systems are relatively low fidelity, but they were cutting edge for 1970s deep space missions such as the Voyager probes. Voyager 2 used such a vidicon camera to shoot humanity’s only up-close photos (so far) of the seventh planet, Uranus, and its faint system of rings. This example (below), processed by space-imaging guru Ian Regan, highlights the extremes of performance of early deep space digital cameras. The bright and bluish disk of the planet itself, while bland and cloud-free during the Voyager 2 flyby, reproduced nicely in the camera. But, Regan told me, “I wanted to experiment with the data and produce a composite showing the faint traces of its slender ring system. Enhancement of the vintage TV camera–derived images does indeed reveal the moderately bright Epsilon ring, but also unveils the inevitable carpet of background noise and moiré-like patterns.” Such extreme processing might be the only way to pull out subtle discoveries from noisy data, and as Regan noted, might be an inevitable result of “pushing data borne of 1970s technology to its very limit.”

New opportunities to view Uranus are in the works: In its decadal survey released in April 2022, the National Academies of Sciences, Engineering, and Medicine recommended the planet as one of NASA’s next big targets. In such a mission, an orbiter and atmospheric probe would be launched to Uranus in the early 2030s. With the help of a gravity assist from Jupiter, the spacecraft would arrive at the ice giant 13 years later and start collecting images that Regan and other processors can transform into new art.

Verona Rupes on Miranda

It has taken 60 years to get to know our planetary neighborhood, photographing and mapping the worlds around us up close for the first time. A notable result, I claim, is that we now know where most of the extraterrestrial natural wonders of our Solar System can be found. These places will be meccas for nature lovers, hikers, and photographers in the centuries ahead. One such place on my personal list is a 20-kilometer-high sheer ice cliff called Verona Rupes (above). It was discovered in 1986 on Miranda, a small icy moon of the planet Uranus. This stunning Voyager 2 flyby photo of the cliff is our only good view of it, and it probably doesn’t do it justice. Even though Miranda is only about 500 kilometers wide (with the same surface area as Texas), Verona Rupes is the tallest known cliff in the entire Solar System. If (when) you could cliff dive there, it would take more than 12 minutes to get to the bottom because of Miranda’s gravity, which is less than one one-hundredth of Earth’s. This photo terrifies me because of my fear of heights, but at the same time I am strongly drawn to it because I’m convinced that this place will be treasured in the future by our descendants.

Neptune and Triton

The Voyager 2 mission’s “Grand Tour” of all four giant planets in our Solar System from 1979 to 1989 was a once-in-a-generation epic journey of discovery. The voyage was documented in thousands of stunning, historic, and scientifically compelling photos. Some of the most beautiful and poignant images came at the culmination of the tour, during the flyby of Neptune in 1989. With nothing left to lose, controllers sent the spacecraft careening just above the cloud tops of this distant, azure world, using the planet’s gravity to propel the probe toward a close encounter with Neptune’s large moon, Triton. Both encounters yielded photographic treats such as those showcased here. The close-up view of Neptune (below) shows white upper-level clouds of super-cold methane. Despite the incoming sunshine being 900 times weaker than at Earth, those clouds are buffeted by the strongest winds in the Solar System, with speeds up to 2,000 kilometers per hour. The wide-angle view (above) shows the crescents of Neptune and Triton as the spacecraft departed its last “port of call.” Never before, and perhaps never again, will so many new worlds be revealed in a single expedition. As Voyager camera team member and one of my planetary science mentors Larry Soderblom has said, “You can only discover the Solar System for the first time once.”

Zigzagging Across Pluto

Some astronomers classify worlds according to where or what they orbit. But in my experience, most planetary scientists classify worlds according to what they are like. As an example, this gorgeous wide-angle photo (above) taken just 15 minutes after closest approach by the NASA New Horizons space probe flyby mission, processed and colorized masterfully by Regan, provides one of the most compelling justifications I know of for classifying Pluto as a planet. Yes, it is a small world in a tilted and eccentric orbit far from the Sun. But it is round from its own gravity. It has an atmosphere, with more than a dozen haze layers highlighted by the backlighting here. Pluto has sprawling icy plains and rugged icy mountains and glaciers, indicating a complex geologic history and an interior likely segregated into core, mantle, and crust. It even has five moons of its own, including one half its size named Charon that is probably also a planet in its own right. “No Earthbound telescope can ever depict distant worlds in such a way, and no other image from this encounter struck such a nerve,” Regan told me. He finds the photo profound (and I agree) because “it gave palpable confirmation that, finally, Pluto had become a world reconnoitered by humanity.”

Higher-resolution zoomed-in photos of Pluto’s surface only enhance the surprise and delight in discovering so much evidence for geologic activity and complexity on such a small and distant planet. The photos above and below were taken on the same date, but the images have been processed differently. The collage (above) shows the planet in light visible to the human eye, whereas the wide-angle image (below) is a colorized infrared composite that enhances differences in surface composition and physical properties. These images—among the most detailed shot during the NASA New Horizons flyby back in 2015—show a staggering variety of linear faults and circular craters, smooth to rugged textured plains, mountains more than 5 kilometers tall, and strong tonal contrasts among terrains suggesting major variability in ice composition. Where did all the heat and energy come from to drive all this action? This world is 30 to 50 times farther from the heat and light of the Sun than Earth. Tidal forces between this dwarf planet and its five moons are fairly weak. It’s made mostly of ice, not rock, and thus lacks the radioactivity that heats rocky planetary interiors. What’s going on here in these spectacular and artistically compelling landscape photos from the far reaches of our Solar System is a profound mystery, but one that we need to solve if we’re ever going to truly understand planets—of all sizes. No one knows when we’ll ever go back there with orbiters, landers, or rovers. But I believe that views such as this convince us that we must.

Excerpted and adapted with permission from The Art of the Cosmos by Jim Bell (2022, Union Square & Co.).