Everyone likes a good space photo. They're colorful, they're otherworldly, they make an inoffensive desktop background. And that's not to trivialize them: Artists’ renderings of exoplanets are gorgeous, imaginative visions of what it might look like to live your life circling another star, and they're devilishly tricky to make.
Images sure don’t come straight out of space telescope looking press-release ready. Each visualization is the result of artists and planetary scientists collaborating to convert blips on a data readout into something that looks like a planet---all while remaining scientifically plausible. It's a tricky balancing act that doesn't always go smoothly. But the illustrations are genuinely useful. They don't just get regular people fired up about exoplanets, they help scientists working on the systems articulate their work's importance. And in the incredibly expensive field of space science, you've got to be exciting to get funded.
For now, exoplanet science seems to be in the black---and you can expect a lot more of it. The Trappist-1 system, which boasts seven Earth-like worlds orbiting a dwarf star, might be your current source of exoplanet visualization porn, but planetary scientists are already looking toward other systems. At the Breakthrough Discuss Conference last week, scientists were hopeful not only about continuing study of Trappist-1 exoplanets and the over-hyped, not-all-that-Earthlike Proxima Centauri b, but also the data due to be collected by Speculoos, a telescope system designed to Search for habitable Planets EClipsing ULtra-cOOl Stars. (Apparently getting yourself a catchy acronym has become a case of the tail wagging the dog.) Speculoos' four one-meter diameter telescopes won't just spot exoplanets, they'll survey those planets for hints of life like carbon dioxide and ozone.
Newer instruments make exoplanet artists' lives much easier. "In the early days, there was real tension between the artists and scientists because there wasn’t that much data known," says Lisa Messeri, aspace anthropologist at the University of Virginia and author of Placing Outer Space. "Astronomers never wanted the artists to be too evocative." It's easy to see why artistic renderings of discoveries could get on scientists' nerves. Much of the data that comes back from telescopes like Trappist or Kepler is more useful in developing hypothesis and designing future missions to gather more information: ranges planets' mass or location could fall within or other suggestions scientists extrapolate from. Renderings can make it seem as though an exoplanet's features are knowable in far greater detail than science can currently provide.
The artists also have to contend with the whole Earth analogy problem. "We try to make our artwork look different from the Earth whenever we can," says Tim Pyle, a multimedia artist at NASA's Jet Propulsion Laboratory. "We don't want to accidentally imply that we've found another Earth." (According to Messeri, making too many comparisons to Earth is something planetary scientists get dinged on by their peer reviewers when writing about exoplanets, so it plagues the exoplanet field at large.) Making a planet feel relatable to an Earth-bound human without making it feel like Earth is a fine line to tread.
But even though trying to make accurate Earthy-but-not-too-Earthy renderings of planets might seem like a futile exercise, it's actually a valuable scientific puzzle. "Scientists see beauty in light curves and radial velocity graphs. They can get as excited at looking at these data as looking at landscapes," Messeri says. "But the relationship scientists have with artists forces them out of the clouds, and to translate from the data into what this might actually mean." To Messeri, that twist of logic is essential to scientists effectively communicating their work not just to the scientific community, but to the world at large. And that doesn't just make for a sexier press release. It's selling their work with exoplanets as a valuable, fundable scientific target.
