Warning: Major Palm Springs spoilers ahead.
It’s a trope as old as time: Two lonely wedding guests get drunk, then get together. In Palm Springs, though, things take a nosedive shortly after cynical sister of the bride Sarah (Cristin Milioti) and carefree Nyles (Andy Samberg) decide to fool around. When another partygoer abruptly kills Nyles, we learn that he’s been reliving this Palm Springs wedding for quite some time now ever since he first entered a nearby cave. In his own words, he’s stuck in “one of those infinite time loop situations you might have heard about.” Only now, Sarah — who followed Nyles into the cave after their interrupted hookup — is stuck right there with him.
Ever since Bill Murray kept waking up to February 2 in 1993’s Groundhog Day, TV and movie characters have found themselves trapped in time loops. Usually, characters escape the glitchy timeline by finally bettering themselves or helping others (see: the popular YA book and movie Before I Fall, Netflix’s Russian Doll), but Palm Springs takes a less symbolic approach. Nyles, who has now attended Tala (Camila Mendes) and Abe’s (Tyler Hoechlin) wedding so many times that he can barely remember his life before November 9, explains to Sarah that he has tried everything: selflessness, patience, countless escape routes, and suicide attempts. The classic tactics aren’t working. Still, Nyles and Sarah finally make it to November 10. So how do they break the loop?
Sarah is the one to figure it out. After waking up next to her sister’s groom one too many times, she heads to the diner and begins researching quantum physics. She comes to the conclusion that she and Nyles are “trapped in a box of energy,” and the way to escape is to leave the box “in the 3.2 seconds it takes to travel through the loop itself.” During that narrow window of time, she and Nyles will blow up the cave that sent them into the cyclical timeline — along with themselves.
We don’t get a good look into Sarah’s math, logic, or thought process here, and even the language she uses to describe her theory is somewhat vague. This is probably because the laws of physics don’t actually allow for time loops, as we’ve learned from prominent physicists like Stephen Hawking.
That doesn’t mean Sarah’s research is entirely incompatible with real-life scientific theories, though: Physicists have tried to explain warped timelines since the early 1900s. The earliest example might be Albert Einstein’s general theory of relativity, which tells us that space and time merge together into a four-dimensional fabric.
“Einstein’s general theory of relativity allows for the possibility of warping time to such a high degree that it actually folds upon itself, resulting in a time loop,” writes University of Massachusetts physics professor Dr. Gaurav Khanna. In physics, this kind of loop is called a closed timelike curve (CTC); colloquially, it’s known as a time machine.
However, there are too many potential paradoxes in play here for a time loop to work in actuality. The most famous problem, known as the grandfather paradox, asks what would happen if you entered another timeline and killed your biological grandfather. Some physicists (and many Reddit theorists) have attempted to solve this problem using the physicist Igor Dmitriyevich Novikov’s self-consistency principle, which argues that a time traveler would physically be unable to act, in one timeline, in a way that might impact other timelines.
The most realistic part of Sarah’s exit strategy is probably the idea that the route out of a CTC would involve several dimensions of space and time. In Palm Springs, her plan works: After testing the theory out on a goat, Sarah brings Nyles back to the cave. They share a love confession (and enjoy a perfect Kate Bush soundtrack moment), then blow themselves up — and for a few beats, the screen stays black, leaving viewers wondering if we’ll even find out whether Nyles and Sarah make it.
In the film’s final few minutes, we learn that they do: it’s November 10, the wedding is over, and Nyles has to pick up his dog.
“You have a dog named Fred. You never mentioned this,” Sarah says.
“It didn’t come up,” Nyles responds. Given how much banter these two exchanged, this is surprising, but then again, they were mostly focused on the metaphysical glitch that wouldn’t let them leave a destination wedding. Luckily, they now have all the (linear) time in the world to cover other topics — as long as they stay out of caves.