SpaceX’s latest Falcon 9 launch turned the night sky red. It was not visible to the naked eye, but appeared in long-exposure images taken by astrophotographers.
“I photographed the Milky Way behind some rock silhouettes when suddenly one of my pictures had this distinctive red spot right in front of its core, which wasn’t there in the previous picture taken 3 minutes ago,” one of them, named David Johnson, wrote on Facebook.
“I was really upset because it ruined my picture, but I thought it would go away. Instead, it grew in several other images and expanded to cover much of the southeast sky, “he added.
Johnson later realized that the first red-colored image was taken at virtually the same time as the aforementioned SpaceX launch. But before he knew what thing he was most likely looking at, he had no idea what it might be, he said. “It scared me a little,” he admitted in an interview with The Washington Post.
Experts later confirmed that his suspicions were probably correct. Oxygen ions generated by Falcon 9’s second stage react with other molecules in the night sky, which in turn excites electrons and creates a red glow.
“These glows are probably second-stage rocket exhaust gases that cause the ionosphere to recombine rapidly,” explained physicist Jeff Baumgardner of Boston University.
Cover illustration photo: Official SpaceX Photos, CC BY-NC 2.0