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In Stranger Things, the supernatural villain Vecna rules a nightmarish parallel world called the Upside Down. Credit: Netflix\/Everett\/Shutterstock<\/p>\n
Throughout its five seasons, the Netflix show Stranger Things follows a ragtag group of teenagers and their parents as monsters from another universe \u2014 unleashed by the secret work of a government laboratory \u2014 wreak havoc on a quaint, fictional town in Indiana.<\/p>\n
Don\u2019t worry, Demogorgons, Shadow Monsters and psychokinetically gifted 12-year-olds are strictly fictional creations. But the \u2018parallel universe\u2019 concept at the core of the show \u2014 which is set to conclude its nearly decade-long run at the end of this year \u2014 comes from a real scientific theory. And it\u2019s been hotly debated by physicists over the past 75 or so years.<\/p>\n
\u2018Many worlds\u2019 interpretation<\/p>\n
Although the series is as much in the realm of fantasy as science fiction, Stranger Things nods to many concepts of basic physics. Principles of electromagnetism explain haywire compasses, as well as magnets that spontaneously fall off a refrigerator. And in the third season, the characters save the world by using Planck\u2019s constant during their quest to close a gate to the other universe, called the Upside Down (although the show uses the 2014 value for Planck\u2019s constant, which wouldn\u2019t have been standard in the 1980s setting).<\/p>\n
Physicists disagree wildly on what quantum mechanics says about reality, Nature survey shows<\/p>\n <\/a><\/p>\n Perhaps the most prominent physics phenomenon mentioned in the programme, however, is the many-worlds interpretation of quantum mechanics. After deducing that their friend might be stuck in the Upside Down, three pre-teen-boy protagonists ask their science teacher how they could travel there. He responds, \u201cYou guys have been thinking about Hugh Everett\u2019s many-worlds interpretation, haven\u2019t you?\u201d<\/p>\n In the 1950s, the US physicist Hugh Everett really did propose such an explanation for modern physics, and his theory has been collecting devotees ever since. Everett\u2019s work makes sense of a concept that has long baffled quantum physicists: the measurement problem. The question is how a quantum system can seem to be in two states at once \u2014 an electron that is simultaneously in two different locations, for example \u2014 until the moment the system is observed or measured, when all at once it\u2019s in only one of those states.<\/p>\n The most popular explanation for this conundrum, called the Copenhagen interpretation, says that the unobserved electron exists in a hazy quantum state of both options, described only by probabilities, until suddenly, on measurement, it ends up in one. Everett poses an almost fantastical alternative: the electron really exists in both states at once, and after the measurement, an observer sees only one state because the universe branches in two, with each outcome existing in a different world. The countless quantum states of all the world\u2019s particles create an infinite number of universes: hence, many worlds.<\/p>\n Controversial theory<\/p>\n For many physicists, this idea is a bit far-fetched, particularly because if these many worlds can\u2019t interact, then there\u2019s no way to prove or falsify the theory, says Jorge Pullin, a theoretical physicist at Louisiana State University in Baton Rouge.<\/p>\n But for others \u2014 including Sean Carroll, a theoretical physicist at Johns Hopkins University in Baltimore, Maryland, who has worked as a science adviser for science-fiction films \u2014 the many-worlds interpretation is the most elegant explanation out there. \u201cThere are a lot of people who think this is the simplest version of quantum mechanics, and it fits all the data,\u201d he says. Of the many explanations of quantum theory, many worlds is currently the third most popular among quantum physicists, a Nature survey found earlier this year<\/a>.<\/p>\n![\"\"](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2025\/12\/d41586-025-04088-z_51289088.jpg\"\/)
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