Victoria Girgis was leading a public outreach session at the Lowell Observatory in Flagstaff, Ariz., when one of her guests noticed a string of lights moving high overhead.
"Occasionally, you'll see satellites, and they look kind of like shooting stars moving through the sky," Girgis says. "But this was a whole line of them all moving together."
The guest hadn't spotted a UFO invasion. Rather, it was the first installment of billionaire Elon Musk's vision for the future: a constellation of satellites known as Starlink that's meant to provide Internet to the entire planet.
On May 23, Musk's company SpaceX launched a rocket that carried 60 Starlink satellites into orbit. The 500-pound satellites fanned out like a deck of cards. From the ground, they looked like a glittering string whizzing across the arc of the sky.