No, NASA didn't find a parallel universe where time runs backward

Sorry, but the truth is: You're stuck with this universe for now.

Jackson Ryan Former Science Editor
Jackson Ryan was CNET's science editor, and a multiple award-winning one at that. Earlier, he'd been a scientist, but he realized he wasn't very happy sitting at a lab bench all day. Science writing, he realized, was the best job in the world -- it let him tell stories about space, the planet, climate change and the people working at the frontiers of human knowledge. He also owns a lot of ugly Christmas sweaters.
Jackson Ryan
5 min read

There's no mirror universe, sorry.

NASA/Hubble/Jackson Ryan/CNET

Let's play a game of bad news, good news, bad news.

Bad news first: 2020. Literally all of it. Every second. Every waking moment of 2020. It's grim, I know. Bushfires, pandemic, murder hornets. When will it end?

But the good news: Apparently, scientists have discovered a parallel universe, just like our own. It's a little different to ours though. In this mirror world, time runs backward. It's like a Benjamin Button universe. That means they're heading back to 2019, the good ol' days, right?

Well, now more bad news: I'm here to spoil the parallel universe party. Scientists haven't actually discovered a parallel universe, but you might think they have, based on multiple reports from across the web. 

In the last few days a number of publications have suggested scientists "found evidence" for a parallel universe where time runs backward. These mind-bending articles posit that an experiment in Antarctica detected particles that break the laws of physics. All the reports pull from the same source of information: A pay-walled report by New Scientist on April 8 titled "We may have spotted a parallel universe going backwards in time."

At the center of the report are findings from the Antarctic Impulsive Transient Antenna or ANITA, an experiment maintained by researchers at NASA . It involves an array of radio antennas attached to a helium balloon which flies over the Antarctic ice sheet at 37,000 meters, almost four times as high as a commercial flight. At such a height, the antennas can "listen" to the cosmos and detect high-energy particles, known as neutrinos, which constantly bombard the planet. 

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These particles pose no threat to us and pass through most solid objects without anyone even noticing -- some estimates suggest 100 trillion neutrinos pass through your body every second! Rarely do they interact with matter. But if they do smash into an atom, they produce a shower of secondary particles we can detect, which allows us to probe where they came from in the universe. ANITA detects neutrinos pinging in from space and colliding with matter in the Antarctic ice sheet.

Over the years, ANITA has detected a handful of "anomalous" events. Instead of the high-energy neutrinos streaming in from space, they seem to have come from a strange angle, through the Earth's interior, before hitting the detector. These findings can't be explained by our current understanding of physics -- that much is true.

"The unusual ANITA events have been known and discussed since 2016," says Ron Ekers, an honorary fellow at CSIRO, Australia's national science agency. "After four years there has been no satisfactory explanation of the anomalous events seen by ANITA so this is very frustrating, especially to those involved."

Although the New Scientist report was filed on April 8 -- and the ANITA results are almost two years old -- the theory has only recently caught fire. Ever more urgent headlines have spurred its spread across social media. "NASA uncovers evidence of bizarre parallel universe where physics, time operate in reverse" reads one. Another says "Scientists may have just found evidence of a parallel universe." 

Peter Gorham, the principal investigator on ANITA, says it's "some unfortunate tabloid journalism" and notes an early report by the Daily Star "just made some things up about myself and our experiment." 

Because the New Scientist piece is behind a pay wall, many of the subsequent reports on the parallel universe are cribbed from the opening paragraphs and don't explain the full details behind the find, in which one of the scientists admits "there are one or two loose ends" for the parallel universe theory. There's also another neutrino observatory at the South Pole, known as IceCube, which has been following up on the ANITA observations and suggests the standard model of physics cannot explain these strange events.

"In such a situation you start exploring even more extreme possibilities," says Ekers.

There is a really interesting science story here, but it's not the one you're being sold. The ANITA experiment is mind-boggling in its own right. It looks for "ghostly" particles that pass through most matter. It has definitely detected something unusual and unexpected. There are plenty of competing theories that aren't explored in the quick news hits, like the idea the Antarctic ice may itself be giving rise to these anomalous events.

Pat Scott, an astroparticle phenomenologist at the University of Queensland, explains the idea "is plausible" while suggesting there are many, many other theories that can account for the anomalous ANITA detections. "There's nothing that necessarily makes it a detection of a parallel universe," he says.

What this boils down to is simple: There's so much we don't know about neutrinos that astrophysicists and scientists are still trying to unravel. "We are absolutely sure that there is new physics out there to be found," says Clancy James, a radio astronomer at Curtin University in Australia. 

Jumping straight to "parallel universes" is a little over-the-top, and there are less mind-boggling theories that could explain what ANITA has detected. "There are a number of potential candidate particles that could account for the results from ANITA," says Geraint Lewis, an astrophysicist at the University of Sydney. 

"Whilst parallel universes sound exciting and sexy when discussing the ANITA signal, alternative ideas are still on the table," Lewis notes. He also says that doesn't mean the idea is wrong -- but the weight of evidence is currently against it.

Unfortunately, the majority of reports regurgitating this theory without thorough examination of the evidence complicate the public's relationship with science, which is already on shaky ground thanks to misinformation campaigns around climate change and the coronavirus pandemic

When you see stories like these its good to remember "the Sagan Standard", an adage uttered by the famed astronomer Carl Sagan. It goes "extraordinary claims require extraordinary evidence." At present, we've got a great theory but we lack the extraordinary evidence to back it up. 

What we do have, Ekers says, is "a somewhat cheeky explanation ... born out of the frustration of having nothing else that worked." He says this is "good out-of-the-box thinking" and a "fascinating" idea but not one that should be taken very seriously. 

Gorham has requested the New York Post retract their version of the story, but it remains available. 

So, I'm sorry. We didn't find evidence for a parallel universe. Fortunately, if there is one, then over there this article doesn't spoil the theory at all! It supports it! So please, direct all your email toward the parallel universe Jackson Ryan. 

No, I won't be taking questions.

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