Behind the Cover: May 2024

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

When viewed in visible light, Zeta Ophiuchi appears as a dim star in a field of other dim stars. But observed in IR—as it is in the image by NASA’s Wide-Field Infrared Survey Explorer (WISE) that is featured on Physics Today‘s May 2024 cover—the enormous influence of the massive blue star on its surroundings is evident.

The bright yellow gas that curves above Zeta Ophiuchi in the image is shaped by the star’s powerful wind. Streams of particles propelled by Zeta Ophiuchi’s magnetic field create a bow shock, much like a boat does while plowing through the water. In the astrophysical case, the interstellar gas in front of the shock gets compressed and heated, enough for the gas to glow in IR wavelengths.

In the May cover story , astronomers Cecilia Ceccarelli and Claudio Codella explore the causes and effects of interstellar shocks. Within the Milky Way, shocked regions of the interstellar medium often preface the formation of collapsed molecular clouds and new stars. They are key places for researchers to study molecules that may be essential for the emergence of life.

The Physics Today editorial team picked the WISE image over several others because it most clearly shows the hot gas in the bow shock. Art director Freddie Pagani used the typography to lend focus to the words “shocking” and “stars.” She elected to use the font Rocinante Titling in all capital letters for further emphasis. She liked that their thin weight mimicked the wispy lines of gas.