New Delhi: With Stranger Things about to wrap up its nearly 10-year run, the Netflix series is causing controversy yet again way beyond Hawkins, Indiana. The core of the show is a terrifying concept: a parallel universe, the Upside Down, which is seeping into our world through classified government experiments. Although the monsters and mind powers are fantasy, the science behind the idea is almost reality.

According to physicists, the series takes a lot of inspiration out of actual theories in contemporary physics, particularly quantum mechanics. The show is based on actual concepts to have its supernatural narrative, starting with faulty compasses and name-dropping of scientists. A theory in particular, the idea that there might be other universes in the present moment, has baffled scientists for decades and is one of the most disputable explanations of the functioning of reality.

The real science behind parallel worlds

The concept mentioned in Stranger Things is the many-worlds interpretation of quantum mechanics. Hugh Everett, an American physicist, suggested it in the 1950s. The theory tries to answer the classical puzzle in physics regarding the reason for the different behaviour of particles when they are watched, the measurement problem.

Simply, quantum particles may occupy more than one state. An example is that an electron can be at two places at the same time. The Copenhagen interpretation is a traditional thought that implies that the particle only settles in one state when it is being measured. The concept of Everett was more radical. He suggested that everything occurs, but in two different and divergent universes. The two possibilities have their worlds.

Why physicists still argue about it

Several researchers are still sceptical. The main problem is that in case these parallel universes are not able to communicate with one another, it is not obvious how to prove whether they exist. Critics claim that until there is experimental evidence, the theory remains on the plane of philosophy and not physics.

Nevertheless, there are powerful advocates of the idea. A number of physicists are convinced that many worlds is a purer and more rational explanation of quantum behaviour. It does not require an obscure collapse in the process of measurement. A recent survey by Nature made it known that it has become the third most popular interpretation of quantum mechanics among researchers. Although the Upside Down might remain on the screen, the argument regarding parallel universes is still very active in the real world.