October 2017 Discover

THE CRUX

THE LATEST SCIENCE NEWS AND NOTES

October 2017^ DISCOVER^9

HALO HUNTER

Although it resembles an antique portrait camera, this is actually a model of a device called a far ultraviolet camera/spectrograph. In 1972,

Apollo 16 astronaut John Young used the instrument while on the moon to photograph Earth’s geocorona, the ultraviolet halo of light reflected

by hydrogen in the outermost reaches of our atmosphere. The spectrograph helped advance our understanding of the geocorona’s limits, which

we now know to be at least 62,137 miles from the planet’s surface. The camera is on display at the Smithsonian National Air and Space Museum

in Washington, D.C.  ERNIE MASTROIANNI; PHOTO BY ERIC LONG/SMITHSONIAN NATIONAL AIR AND SPACE MUSEUM