Behind the Cover: February 2024

Each month, Physics Today editors explore the research and design choices that inspired the latest cover of the magazine.

The construction of the Allen Telescope Array in 2007 was a turning point in the search for extraterrestrial intelligence. Currently operating with 42 antennas at the Hat Creek Observatory, 300 miles north of San Francisco, the array is the first radio telescope designed specifically for SETI. Featured on the cover of the February 2024 issue of Physics Today, the telescope can simultaneously examine several stellar systems in four frequency bands.

Despite decades of observations, SETI astronomers have yet to identify signals that have the anticipated properties of radio pulses from an alien civilization. As historian of science Rebecca Charbonneau writes in the February cover story , the cosmic silence has prompted astronomers to ask, much like Enrico Fermi did in 1950: “Where are they?”

That question has forced astronomers to ponder the likelihood of the presence of intelligent beings in the universe, their longevity, and, crucially, the implications for humanity. The physicist Philip Morrison called SETI “the archaeology of the future” because it reveals what humans have the potential to become. Such thinking is highly deterministic, Charbonneau writes, but it inspires the imagination as we ponder our future in a cosmic context.

Physics Today production artist Jason Keisling had the unknown in mind when he designed the cover photo of the Allen Telescope Array against the magazine’s logo and cover lines. “For the typography of the title, I wanted something that looked bold and futuristic,” he says, which led him to choose the Video typeface. Keisling layered some letters behind the most prominent antenna in the foreground to give the image depth and make the type look as if it is part of the space in the photograph.