Ko Arimatsu, an astronomer at Kyoto University in Japan, received an intriguing email a couple of weeks ago: An amateur astronomer in his country had spotted a bright flash in Jupiter’s atmosphere.
Dr. Arimatsu, who runs an observation program to study the outer solar system using backyard astronomy equipment, put out a call for more information. Six more reports of the Aug. 28 flash — which, according to Dr. Arimatsu, is one of the brightest ever recorded on the giant gas planet — came in from Japanese skywatchers.
Flashes like these are caused by asteroids or comets from the edges of our solar system that impact Jupiter’s atmosphere. “Direct observation of these bodies is virtually impossible, even with advanced telescopes,” Dr. Arimatsu wrote in an email. But Jupiter’s gravity lures in these objects, which eventually slam into the planet, “making it a unique and invaluable tool for studying them directly,” he said.
Characterizing these flashes is a crucial way to understand our solar system’s history. They offer “a glimpse of the violent processes that were happening in the early days of our solar system,” said Leigh Fletcher, a planetary scientist at the University of Leicester in England. It’s like “seeing planetary evolution in action,” he added.
Today, powerful impacts into Jupiter are a lot more rare, but they do occur. In 1994, one comet