Look Up! There’s an Invisible Zombie Highway Right Above You

According to David J. Smith and his team at the University of Washington and Kostas Konstantinidis and his team at Georgia Tech, there are thousands of species of very small, simple Earth life—bacteria, fungi, viruses—that get swept up by storms and make it to where there’s hardly any oxygen, where the temperatures are fiercely cold, and where they’re no longer protected from solar radiation by the Earth’s ozone layer. And yet, write Peter Ward and Joe Kirschvink in their new book A New History of Life, most of these microbes will eventually come back down to Earth no worse for wear. They’re teeny. You can’t see them without a microscope. Typically, it would take almost 40,000 of them laid end to end to make it around your thumb. Scientists call this new family of creatures-in-the-sky “high life,” and it is a biological zone with its own rules. Up there is not like down here.