Corey Mueller in Popular Science:
Undoubtedly a hit of the summer, Netflix's Stranger Things is a Sci-Fi horror series that utilizes some serious scientific theories. Although they may use some terminology interchangeably, the series dives into some intense, confusing topics in theoretical physics and astrophysics.
Trying to figure out the science behind this piece of science fiction, Popular Science had the opportunity to speak with theoretical physicist Brian Greene, professor of physics and mathematics at Columbia University. Though he's skeptical of the idea of parallel universes and accessing alternate dimensions, he's open and willing to explore the possibility of them. Here's our conversation with him:
In Stranger Things, they use the terminology parallel universes and alternate dimensions, interchangeably. Are these the same? And if not, what's the difference?
No, I mean, they're not really the same. They're related, but you can have a single universe that has more dimensions than the ones that we're aware of. There's reason to think that there might be more dimensions of space beyond our three that we don't see.
Now, you can also have universes, you can also have multiverse proposals — that is, multiple universe proposals — where each universe only has three dimensions of space, and one of time. You can have many universes, each of which has the same number of dimensions that our naive perception suggests to exist: three space and one time. You can certainly put all those ideas together and have a many universe theory in which you also have extra dimensions of space, so they're not mutually exclusive.
More here.