Is the explanation in Stranger Things consistent with what we see?

Question

In the series the Upside-Down is explained by the example of a rope and an ant. So it would be a “continuation” of regular space.

However:

• In the show it seems necessary to use gates to reach it.

• Also it seems the Demogorgon can open gates as it pleases. And it is hinted that it only started after the meeting with Eleven. Let's not forget that from the expanation it takes an incredible amount of energy to pen one.

• Another point is that some objects from the regular world seem to be projected into the Upside-Down - but in the other way from the Upside-Down it is possible to hear/observe(?) the regular world and also manipulate electricity.

• Lastly it seems one gate to manipulate magnetic fields. Given that portals seem to open all over the place - why don’t the others manipulate the magnetic field?

So is there a way where those observations can be explained by this theory?

update

I see i stated my question a bit ambiguous as answers go in the direction of explaining the upside-down. My actual intent was actually to clarify whether the 'ant on the rope' is technobabble or an actual useful description. To give an example chaos theory in jurassic park is also a valid scientific theory woven into the story - although the sections of chaos theory are actually completely disconnected from the story. Or many shows handwave quantum mechanics to explain any magic they want.

So when I read an answer I would consider this: suppose I replace the 'ant on rope' part with 'teleported to another world', 'spirit world (as in night watch - nochnoy dozor), 'from hell' or that D&D story they were refering - does the 'ant on rope' explanation offer any benefit over the 'replacement explanations'. E.g. is "the demogorgon goes along the rope through a gate from the upside-down to the real world" a better explanation than "the demogorgon goes through a gate from hell" - considering how we see things work in the show. Or even better "the demogorgon needs a portal to come along the side of the rope" vs "the demogorgon needs a portal to come from hell" (i really think the rope theory is lacking here).

The answer I am looking for is in-universe, so as @Broklynite points out children logic and knowledge applys (i suppose that would include D&D rulebooks more than real live physics). As observations i would mostly consider what we see in the show. Although characters talking about their experiences is good as well.

update 2

Since it is some time now I was hoping some new information in form of novellizations or screen caps might turn up.

I was pondering about it a little. For one it seems there is a slight indication for the upside-down theory in Els turning over the board game to point to Wills position. Besides I found it noteworthy that none of the characters that physically travelled to the upside-down uses any language even remotly pointing to the theory. I am especially curious about the research lab - they obviously are able to hold an entrance open and have gear for expeditions. They should at least have some theory. I wonder if there is ever a screen or document lying around that might shed some light.

** Update 3 **

With two more seasons out I become less confident with the answer. The teacher in season 3 explanation is a just minor plot device. I don’t recall much upside-down later on. Does it still have any relevance?

Answer 1

Let's take this bit by bit:

First, I'm going to go with the assumption that they are trying to describe the real-world physics of folded dimensions, but that they were explaining it a little differently.

Edit: I say this because there is a classic metaphoric explanation of folded dimensions as an ant on a piece of string which bears a fair amount of similarity to the flea on the tightrope description. Bear in mind that you have as explanation a 1980's conceptualization of physics being dumbed down to the level of a smart child. Given these two things, I feel my assumption is reasonable.

In the show it seems necessary to use gates to reach it.

Yes, there must be a method to reach the alternate dimensions. A gate is as good as any other, but note that Eleven seemed to have been at least partially able to access it through concentration, indicating that while a gate is convenient, the ability to actually perceive the other dimensions may be all that is necessary.

To put this another way, if someone asked you why you don't go back in time , it's just that way and points with their finger disappearing in mid air, it wouldn't really help you.

Also it seems the Demogorgon can open gates as it pleases.

Sure, we don't know how it perceives its surroundings. It also has no eyes.

Another point is that some objects from the regular world seem to be projected into the Upside-Down - but in the other way from the Upside-Down it is possible to hear/observe(?) the regular world and also manipulate electricity.

Again, rather than parallel dimensions, we are talking about dimensions folded in on one another, so it makes a certain amount of sense that each on could affect the other in some ways.

Lastly it seems one gate to manipulate magnetic fields.

See the previous point. Nothing prevents electromagnetic fields from being affected.

Given that portals seem to open all over the place - why aren’t there more?

How do we know there aren't, and they're just opening and closing all the time? The portals mostly seem to have a short lifespan, so who knows if they are even noticed. Is the monster using the portals or creating them? We have seen them both together and independent of one another, so we don't necessarily know where they come from. It could be that you have local nodes where the activation energy necessary to create a portal is particularly low. We just don't know.

Edit: okay, I think I may have a slightly better grip on your question. I think you are asking about how well the flea on a tightrope metaphor works to explain everything. Ultimately it doesn't, it's a metaphor. It serves to explain the idea of our current timeline, the ability to leave it, go to another one, return, our limitations. It's a way to grasp the idea of our dimension versus other dimensions. And that's about it. It breaks down when you try to use it to explain electromagnetic effects, portals, all that. The portals indicate the necessity to tunnel through dimensions rather than leap between them, for example. Leaping means one person can do it, but anybody can use a tunnel once made. So, yes, the metaphor breaks down.

Answer 2

Plenty of other sci-fi stories involve travel from one place to another within the same universe via 'gates' or 'portals'. The concept that the two worlds in Stranger Things are connected doesn't mean that they can't use portals to jump from place to place rather than take 'the long way around', whatever that might be.

The Demogorgon's ability to open doors needn't be seen as an inconsistency - the abilities of creatures from the upside-down is constantly being explored. In the 'real' world, attempts to open or maintain doors appears to be heavily dependant on organic matter as much as hard tech, so perhaps they are just trying to mimic inherent abilities of creatures such as the Demogorgon.

One of the endearing features of Stranger Things is that everything is seen from the perspective of younger children. As such, many of the explanations are childlike and not as detailed as you might expect in other science fiction. The 'science' element of the show may not stand up to as much scrutiny as other shows. I am certainly not getting too hung up on that and trying to enjoy the show as it is presented.