The science behind Hulu’s ‘Palm Springs,’ explained by physicists
Warning: Major spoilers ahead for the Hulu movie “Palm Springs.”
Most people would probably say there has been at least one day in their life that deserved a redo.
After finishing the new Andy Samberg and Cristin Milioti romantic comedy “Palm Springs,” you may be wondering if there really is a way to get that second chance, or if your next trip into a cave after an earthquake will trap in you in some sort of never-ending time loop of your sister’s wedding like it did in the movie.
Never fear: The Arizona Republic talked with two experts, one particle physicist and one astrophysicist, who agree this isn’t something that could happen accidentally on Earth. This does not mean, though, that time loops are a physical impossibility out there in the universe.
Daniel Whiteson, a professor of particle physics at University of California Irvine, broke down the possible scientific explanations behind the time loop that forces characters Nyles (Samberg) and Sarah (Milioti) to relive the same day forever.
“It’s possible to have these closed time loops in general relativity,” Whiteson said, talking about Albert Einstein’s 1915 theory of general relativity that provides the bedrock of modern physics and our understanding of the universe.
General relativity describes how massive objects like planets and black holes warp both space and time, like a bowling ball on a trampoline. The warping of space and time, or as physicists call it, spacetime, is what causes gravity.
In a real closed time loop, though, the exact same thing would happen at every point in the loop with no space for variation — meaning the characters wouldn’t remember what happened the “day” before like they do in the movie.
When Sarah realizes something weird is happening with space and time in the Palm Springs cave, she teaches herself more about physics and the fabric of the universe to get out of the endless loop.
While the field of physics is accessible to anyone who wants to learn and teaching yourself is welcome, Whiteson said, Sarah would need a lot of time to become an expert like she does in the movie.
“I think it would be a decade of afternoons in a coffee shop before you could be teaching Cliff Johnson things about black holes,” Whiteson said, referencing the part in the movie where Sarah video chats with Cliff Johnson, a noted physicist at the University of Southern California. Johnson served as a scientific advisor on this movie and is often a scientific consultant on films that involve time travel such as “Avengers: Endgame.”
What Sarah found out about the science of the time loop predicament from her research isn’t exactly specified, but Whiteson suggests a few possibilities. One is a wormhole.
“There is a good reason to think that in our universe, it’s possible that when you go inside a black hole there is a connection inside the black hole to somewhere else in the universe,” Whiteson said. This “tube” or wormhole could take you to another part of the universe in space, but also time.
“That’s a totally reasonable thing in theoretical physics. Obviously, we’ve never seen it.”
Wormholes don’t work exactly like the cave does in the movie though. They should have an entrance and a separate exit. Whiteson said everyone who traveled through a wormhole would end up in the same place, meaning they would not wake up in separate bedrooms or towns, for example.
Summer Ash is an astrophysicist and senior STEAM education specialist for the National Radio Astronomy Observatory in Socorro, New Mexico who also agrees that space-time might go “crazy” inside of a black hole and cause something like a time loop or a wormhole, but “you would never get inside a black hole without knowing it.”
So, no worries about wandering inside of one in the California desert.
A wormhole also would not likely be destroyed by an explosion of C4 like in the movie Whiteson said. On the contrary, a constantly exploding bomb would help keep the wormhole open because it would need the supply of energy. “It’s the kind of thing that would naturally destroy itself.”
Or, Whiteson said, there is always the possibility the “Palm Springs” wormhole could be some “weird exotic kind” that acts unlike anything scientists have theorized before.
There may be a better explanation for this time loop than a wormhole.
It’s not just a thing of sci-fi books and movies: There is a real hypothesis that our existence and the entire universe as we recognize it is all a simulation, much like a computer program we live inside of but don’t know about. The hypothesis is based on the philosophical argument that if civilizations in the universe live long enough to develop advanced technology and enormous computing power, they could create simulated worlds.
“I think that is the most plausible explanation in the whole movie,” said Whiteson. This is most likely, he said, because in a simulation there are no rules. “You could do whatever you like, you can kill people...you can do basically anything.”
The real mind-bender: Whiteson said he could write a simulation where the events of the movie happen to him. In fact, it has already been done.
“We have created the simulation [of the time loop], it’s the movie.”