This story originally appeared in the December issue of Discover magazine as "Science...or Just Fiction?" Support our science journalism by becoming a subscriber.
When physicist and author Stephen Webb was a kid in the 1960s, humans were finally reaching beyond Earth. Satellites orbited the planet. Rockets blasted people into space. Astronauts walked on the moon. And in the distance, Mars, with its red soil and hints of ancient water, titillated imaginations and beckoned Earthlings onward.
“I grew up — I guess you’d say — in a science fictional world,” says Webb, a bald British man whose alternately arched and furrowed eyebrows can tell a story of excitement and confusion almost as well as words do.
During that same childhood period, he was immersing himself in actual science fiction, in addition to this nonfictional reality that was so cool it seemed fake. He devoured books by canonical authors like Robert Heinlein and Isaac Asimov. In the universe-webs the writers spun, humans rocketed around and interacted with interplanetary species. That lens shaped his view of everything — and everyone — in space. He came of age, he says, with “that idea that the galaxy contains weird and wonderful life-forms that one day we would go out and meet.”
Webb held on to that idea tightly — until, that is, as a young man studying physics, he read an August 1984 article in the magazine Asimov’s Science Fiction, written by geologist and science fiction author Stephen L. Gillett. It was called simply “The Fermi Paradox,” and it proposed something Webb had never considered: If the universe is so big, it likely produced intelligent life on other planets. Some of those lives must have built spaceships. Even at relatively slow speeds, given enough time, they’d disperse across the galaxy, just as humans had across the globe. And if that’s the case, as physicist Enrico Fermi famously wondered, where is everybody? Why haven’t we met any extraterrestrials?