We’re all familiar with the concept of parallel realities: universes much like our own, but impossibly out of reach when it comes to communicating with them—or at least so it would seem. A series of experiments has been scheduled to be run this summer to see if a mere handful of particles could be successfully changed into their mirror counterparts by sending them into a “mirror universe”—a realm similar to our own, but one that follows a different set of physical laws.
In the 1990s, physicists studying how neutrons decay into protons, both being subatomic particles found in the nucleus of an atom, encountered a perplexing phenomenon: neutrons produced from particle beams, like the Large Hadron Collider at France’s CERN laboratory, would last for an average of 14 minutes and 48 seconds before decaying into protons; however, ordinary neutrons stored in laboratory containers only lasted for an average of 14 minutes and 38 seconds before decaying—a full ten seconds sooner than their particle beam-brethren.
But both groups of particles should decay at the exact same rate, since they’re both comprised of neutrons, leaving physicists with a perplexing discrepancy.
“I take discrepancy very seriously,” explains Benjamin Grinstein, a particle-physics expert at the University of California, San Diego. And the discrepancy between the two neutron sources wound up being compounded with further experimentation.
“It’s not just between two experiments,” Grinstein adds. “It is a collection of many experiments done independently by several groups. The newest experiments, conceived in part to resolve the disagreement, have only made it worse.”
One concept that would explain the difference in the neutrons’ decay rates is that some of them might actually be “mirror matter”, a result of ordinary neutrons crossing over into a mirror universe, making it appear as if they had vanished from ours entirely—an effect that would skew the average in decay times from previous experiments. If the mirror particle explanation is correct, that would mean that physicists had inadvertently opened a miniscule doorway to a mirror universe.
Enter physicist Leah Broussard, of Tennessee ‘s Oak Ridge National Laboratory, who plans to conduct a series of experiments this summer to test the mirror universe theory. Her experiment is a simple, yet high-precision endeavor: a particle beam of neutrons will have its oscillations tuned using an array of powerful magnets, which will then be directed at a solid and otherwise impenetrable wall. If the experiment is successful, some of the neutrons will transform into their mirror-universe counterparts, and pass directly through the wall.
“It’s pretty wacky,” Broussard admits, regarding her experiment. Oak Ridge is home to an 85-megawatt nuclear reactor that will provide all the free neutrons she needs for the experiment; the hard part is not only figuring out how to coax these neutrons into skipping universes, but also to prove that such an event had happened.
“It all comes down to: Are we able to shine neutrons through a wall?” Broussard explains. “We should see no neutrons according to conventional physics theory. If some of them show up anyway, that would suggest that conventional physics is wrong, and the mirror world is real.”
A similar experiment has already been conducted at the Paul Scherrer Institute in Zurich. In this experiment, physicist Klaus Kirch contained slow-moving neutrons and exposed them to a magnetic field; currently, he is tallying them to see if all of the particles involved are accounted for, and if some are missing, this might be evidence that some have absconded to a mirror universe.
Yet another physicist, Zurab Berezhiani, with the University of L’Aquila in Italy, says that evidence for a mirror universe may be all around us—literally—in the form of dark matter, a phenomenon that theoretically makes up 80 percent of the universe’s mass, but one that we can’t otherwise detect. If dark matter indeed resides solely in a mirror universe, that would account for our inability to detect it, despite its gravitational pull affecting the structure of all visible matter in our universe.