The dream of an interstellar Earthling diaspora, one that could guarantee our continuation as a species, is hugely appealing, both as grist for science fiction and as a road map for our human future. But for Chiao, who is stoic on these matters, deliverance in space is a mirage.
“It’s important to develop a way to deflect asteroids and develop a way to have humans sustainably live on a place like Mars, but to me, at some point we end,” he told me. “I know it sounds a bit odd, but there’s some comfort in that knowledge. We’re not in this race to save ourselves. There seems to be order in the universe, and probably every group of intelligent life has its own cycle. It’s okay to be extinct.”
In that scenario, our robotic spacecraft may outlive us. Even now, they are our most daring emissaries: They can surf the sun, explore hostile planets, and even break into the interstellar frontier. But while these spacecraft are our scouts, many people will always prefer to see themselves in space. “People identify when there’s a human out there doing it,” Chiao told me. “We’re just thrilled and amazed to see what comes back from these robotic probes, but I think you need both.”
Weibel points out that during the Apollo era, robotic spacecraft took pictures of Earth from lunar orbit. But it wasn’t until Bill Anders, an astronaut on board Apollo 8, snapped the famous “Earthrise” shot that the otherworldly view really hit home for the public. Similar shots from the Artemis II astronauts went viral, including a picture of Christina Koch gazing through the spacecraft window at Earth.
There are lots of reasons for humans to stay grounded, from the dangerous nature of spaceflight to the medical complications of long-term radiation exposure to the gargantuan expense. But it is unlikely we will stay put on Earth, even if we never make it far—for the same reason our ancestors crossed deserts, oceans, and mountains.
“Knowing somebody’s been there and can tell us about it when they come back—that’s a whole other level of it that makes it more compelling,” Weibel told me. “I’m not 100% sure why,” she adds, “but we trust witness testimony.”
Becky Ferreira is a science reporter based in upstate New York and the author of First Contact: The Story of Our Obsession with Aliens.