When Catharine Conley started her job at NASA, her predecessor gave her a pair of dark Ray Ban sunglasses. It’s only fitting — Conley is a real-life version of the famously shaded title characters in the 1997 movie Men in Black. Part of her job as planetary protection officer is to keep Earth safe from alien life. But, as far as we know, Earthlings are the ones regularly hopping around the solar system, so most of her job is to protect aliens from the human race.
When humans — or our robotic stand-ins — travel to new places, we take more than we think with us. It’s nothing new; biological stowaways have been hitching rides on terrestrial voyages for centuries. Christopher Columbus’ trip to North America brought deadly diseases that wrought havoc on the Native Americans. In the 1800s, British rabbits were released into the wild in Australia, and they’ve been a multimillion-dollar nuisance to farmers ever since. And the winding, climbing kudzu plant, native to Japan, chokes other plants in the Southern U.S. “We have enough experience on Earth to know that unexpected things can happen,” Conley says.
With the launch of the Russian satellite Sputnik in 1957, and the promise of traveling into outer space, came the realization that if anything were growing out there, our arrival might upset its biology. A space-age species invasion could damage not just alien organisms, but also the opportunity to study them properly. Most benignly, spacecraft stowaways could make for a tough sorting game — is this creature an Earthling or Martian? — or be mistakenly identified altogether. Worse, Earth organisms could infect or kill the alien ones that we went through so much trouble to visit.
