The mystery of the strange purple ribbon in the North American night sky is solved, with NASA’s help.

Starting in 2015, amateur astronomers saw something unusual over Canada. A streak of purple lit up in the sky that looked different from the northern lights. Not knowing what to call it, they settled on “Steve,” choosing that name on a lark.

NASA says Steve is not a normal aurora. Auroras occur around the north and south poles in an oval shape, last for hours, and appear primarily in greens, blues and reds. Steve is purple with a green “picket fence” structure that waves and has a beginning and end. People have observed Steve for 20 minutes to 1 hour before it disappears.

Red and green streaks in night sky (Courtesy of Megan Hoffman/NASA)
“Steve” sometimes features greenish streaks of light. (Courtesy of Megan Hoffman/NASA)

Thanks to amateur photos, U.S. and Canadian telescope snapshots, and a European Space Agency satellite flyby, the mystery is solved: Steve is a different kind of aurora caused by hot, fast particles moving along electric and magnetic fields in the atmosphere.

Liz MacDonald, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said the phenomenon can help us understand Earth’s magnetic environment and improve satellites and communication signals. “Gathering more data points on Steve will help us understand more about its behavior and its influence on space weather,” MacDonald said.

Green streaks and purple light in night sky (Courtesy of Megan Hoffman/NASA)
Steve is visible further south than the aurora borealis. (Courtesy of Megan Hoffman/NASA)

If you’re planning a trip to Alaska or another northern U.S. state, Canada, the United Kingdom, or even New Zealand, you’ve got a chance to see Steve. NASA has tips. Report sightings to Aurorasaurus, a hub of citizen science funded by NASA and the U.S. National Science Foundation.

The latest news called for a more scientific name for the phenomenon. So the purplish cousin of the aurora became the Strong Thermal Emission Velocity Enhancement phenomenon, or STEVE. Can’t let a good name go to waste.