It's a variation of Newton's first law: Bikini-clad Snapchatters in motion will stay in motion unless acted upon by an outside force — in this case, Bill Nye the Science Guy.
That irrefutable truism was proven in Las Vegas on Friday, when Savana Prosch and four friends, in town for the Life is Beautiful Festival, were filming themselves twerking in an elevator mirror for a Snapchat video. In the clip, the doors open on another floor and in walks 61-year-old Nye, wearing his trademark bow tie.
The "Bill Nye Saves the World" star was in town to give a talk at the festival that day.
"Hi girls," the engineer-turned-television personality says as the women go quiet (for a moment) in stunned recognition.
"He wasn't expecting to see a bunch of girls try to pretend like they weren't doing something he definitely saw," Prosch told Storyful.
But Nye didn't seem too perturbed. He filmed a parody re-creation for his space exploration advocacy group, The Planetary Society, two days later:
It's all in the name of science!