Scientists have solved the mystery of a spinning ball of bluish light that slowly swept across the Alaskan sky last month and stole the show from the famous Northern Lights: the unusual ball was most likely debris from a Chinese missile that flew overhead.
Eyewitnesses across the state spotted the strange phenomenon around 5 a.m. local time on March 29. “It seemed like something was spinning,” Leslie Smallwood, a Fairbanks resident who witnessed the event, told the local news station KUAC (opens in new tab). The sphere appeared much larger than a full one moon and moved from the northeast to the southwest, he added.
An automatic camera trap captured images of the sphere grazing in front of them northern lights (also called Northern Lights). The Camera Trap, operated by The Aurora Hunters (opens in new tab) Ronn Murray and Marketa Murray, a Fairbanks couple who run Northern Lights photo tours, regularly take photos of the sky every 45 seconds so people can experience the Northern Lights in near real time. The camera took six photos of the sphere, suggesting it was visible for at least four and a half minutes.
“It’s not like it shot out of the sky,” Smallwood told KUAC. “It was like taking your time.”
The bullet came and went with no real explanation. However, after analyzing the photos, scientists determined that the large blue orb was likely the result of a Chinese photobombing missile.
“I’m very confident that what people saw was a Chinese rocket stage defuelling,” Jonathan McDowell, an astronomer at the Harvard Smithsonian Center for Astrophysics in Massachusetts, told KUAC. The bullet matches the trajectory of a Chinese rocket that launched two satellites into orbit, he added. The rocket was a Long March 6 two-stage launch vehicle launched from Taiwan, according to a tweet (opens in new tab) by McDowell.
The rocket likely released leftover fuel into space, where the fuel froze and expanded into a large sphere illuminated by sunlight, McDowell told KUAC. “This cloud is probably hundreds of kilometers across; that’s why it looks so big,” he added.
Other scientists agree with McDowell’s explanation. “A glowing cloud of gas in sunlight would look like this,” Mark Conde, a physicist at the University of Alaska Fairbanks, told KUAC.
The sphere appeared to spin because rockets, when they dump their fuel, fall into a controlled fall to maintain the rocket’s orbit. The rocket would have “spun end over end while spewing that fuel out like a garden hose,” McDowell said.
This is not the first time this phenomenon has occurred. In October 2017, an even larger blue ball was seen in the sky over Siberia science alert (opens in new tab). On that occasion, the frozen fuel from Russian military missile tests was left in the area.
Originally published on Live Science.
