My problem with portals

[Amazon]

I love the idea of portals; they are one of my favorite fantasy\sifi concepts.

I really prefer "opaque portals" the kind where you can't see the other side, the ones used by Quan Chi for example:

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They are just a whirlwind of energy, my problem comes that such portals have two sides and I can't help but wonder what happens if someone cross the portal in the "wrong side".

Such problem can be solved by only having portals in flat surfaces, like the ones in the video game "Portal"

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This way there is only one side that can be cross and the "Wrong side" is inaccessible.

The same effect can be reached by having different shapes for your portals such as skyrim that used a spherical one.

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This "wrong side" problem is even worst when the portals are "transparent" such as the ones in Doctor strange, in other words you can see where you are going to end up, that raises two questions, what happens if you cross the wrong side and what does the other side look like?



And they never show the other side of portals like that, NEVER! I have never seen a movie, video game, cartoon, comic, manga etc... That shows a non flat surface portal back. That has been bugging me for my entire life.

So basically what I want to know is:

What does a portal look like in the “wrong side”?
What happens if you cross a portal “wrong side”?

[Lethologica]

It probably looks like a blank glow of energy, and you probably can't cross it, but it's not like it's established in these stories so you're free to imagine whatever you want.

[Durkoala]

Philip Pullman's His Dark Materials has the other side of the portal simply not exist. From the back, you have an uninterrupted view of the local landscape.

[Lord Raziere]

Well we're talking about a hole in space. its not exactly a thing of well-understood geometry or physics. personally I like ether of two possibilities:

the backside of the portal is just as a valid part of it as the front to enter, you just exist from the back of the other portal as well.

or, the portal is a strange thing of eldritch abomination geometries, where there isn't any portal back- wherever you turn, its always the front to you. it still looks two dimensional, but its always facing you to your perspective. this can be quite confusing when two people look at it from different angles, as they each claim its facing them.

[Cikomyr]

Lets say you have a portal with 2 ends. Each end has a side:

A|B

C|D

If you enter through A, you will end up in D.
If you enter through B, you will end up in C

See the portal like a space shortcut between the spaces located between AB and CD.

[TeChameleon]

I'm almost certain I've encountered some form of media (probably a video game..?) where you can see the 'wrong' side of the portal, since I actually had a knee-jerk response to the question- i.e. that the 'wrong' side is just a blank whirling mass of energy the same colour as the portal border that acts as a wall- but I couldn't even guess where it was that I saw that. Huh.

[Rynjin]

So basically what I want to know is:

What does a portal look like in the “wrong side”?
What happens if you cross a portal “wrong side”?

I've always assumed the answers are A.)The same as on the "right" side and B.) Same thing that happens on the "right" side.

It's a hole in space (and sometimes time). The hole leads from point A to point B, like any other hole. The only difference is the hole is suspended in air so you can get "behind" the hole at point A and still see into point B.

[Bohandas]

Philip Pullman's His Dark Materials has the other side of the portal simply not exist. From the back, you have an uninterrupted view of the local landscape.

But what happens if you step through? It seems like you would be bisected. The parts that went past first would no longer be in contact with the parts that hadn't gone past yet, instead they would be in contact with the other side of the portal

[Bohandas]

Of course the best solution is to have spherical portals that don't have a back or edges

[Lethologica]

But what happens if you step through? It seems like you would be bisected. The parts that went past first would no longer be in contact with the parts that hadn't gone past yet, instead they would be in contact with the other side of the portal

On a storytelling level, there are no parts. It's a fantasy portal--it responds to entities, not matter. If you're going through the back of the portal, the portal doesn't exist for you while you're doing that.

On a physical level, you're essentially right, but it's a tad more complicated than how you describe it.

You won't be bisected--"the parts that went past first" are still in contact with "the parts that hadn't gone past yet," because the space on the back side of the portal is still connected to the space on the front side of the portal. It's just that the space on the front side of the portal is also connected to the space on the far side of the portal. The connections aren't path-independent, which is what's messing with your intuition.

The people on the far side of the portal would get an interesting show of internal organs as you stepped through, though. And this suggests the real reason you would die if you went through the portal the 'wrong' way (back to front): a lot of the squishy stuff inside you that's past the portal would immediately go backwards through the portal the 'right' way (because there's no pressure keeping it from doing so) and end up a pile of bloody mess on the far side of the portal. Congratulations, you've basically imploded yourself.

EDIT: Wait, that can't be right, because if you can still see the space in front of the portal from the back, then information is traveling through the front of the portal and coming out the back instead of the far side. So from the back of the portal there's a two-way connected space with the front side, and from the far side of the portal there's also a two-way connected space with the front side. There isn't a clear physical explanation for that (which is okay), but it does imply that you can go through the back side of the portal and be just fine.

[factotum]

And they never show the other side of portals like that, NEVER!

Er, but the picture you posted is showing exactly that? We're not seeing the side of the portal created by Strange there, we're seeing where it comes out at the other end. From what we've seen, the portals in Dr. Strange are two-way and symmetrical, so the nurse in the photo could theoretically walk into where Strange is, if she had any reason to want to do so.

[Anonymouswizard]

Alright students, welcome to An Introduction to Instant Travel. While previously instant travel was accomplished via information transfer, the discovery of the soul has caused us to discover that this causes death. Therefore for the last one hundred and fifty years the preferred method of instant travel has been wormholes.

Yes, I know that many of you have heard them referred to as portals by mystical types, but here at Anonymouswizard's School of Scientific Sorcery we prefer the term wormhole.

Now wormholes come in many forms. If you every travel to another dimension make certain you know how the wormholes in that dimension work, otherwise you may end up disintegrating yourself. While that will potentially help humanity become a species that doesn't use a wormhole without proper research it will be a bad day for you.

Wormholes come in two shapes, flat and spherical, and three types, opaque, transparent, and invisible. The two shapes are self explanatory, a flat wormhole has no depth and a spherical one looks like a ball.

The three types refer to what a wormhole looks like. Opaque wormholes tend to look like a swirl of energy, although there have been observed variations depending on how exactly they function this is not relevant until the advanced level. Transparent wormholes allow you to see what's on the other side, and as such have become the most popular type among the general public. Meanwhile invisible wormholes cannot be seen from any direction, take care that I you walk through one you can find your way back.

Now, there are also two way and one way wormholes. Extensive research has shown any matter entering the 'wrong' side of the wormhole is disintegrated and a burst of hard radiation is remitted at the other end. While there have been proposals to use this to generate electricity research has been suspending until research into how to safely stop our 'perpetual falling machine' bares fruit.

Finally, some wormholes have what is commonly referred to as a 'back'. This is not present on all wormholes, as some have two fronts, and tends to look like a solid sheet of one colour. Take care when dealing with a wormhole back, as it acts in the same way as the terminus of a one way wormhole.

Finally, despite it being a common misconception, there are spherical wormholes with a back. This will be either the inside or the outside of the sphere, so make sure you know it's safe before interacting with a spherical wormhole.

Next week we will discuss special geometry, which is the basis of all attempts to make a wormhole.

[theNater]

And they never show the other side of portals like that, NEVER! I have never seen a movie, video game, cartoon, comic, manga etc... That shows a non flat surface portal back. That has been bugging me for my entire life.

Warcraft does this. Some humans are fleeing through a transparent portal, and a few of the pursuing orcs think of going around to the back of the portal. While there, they can see the humans running towards them, but the humans vanish upon reaching the portal boundary, and any attacks the orcs try bounce off their side of the portal.

[Vogie]

I'm fairly sure there was a Stargate episode where people were killing themselves by diving into the "wrong" side of the titular Stargate... I believe it's the one when they're trapped on the Prison planet?

Warcraft does this. Some humans are fleeing through a transparent portal, and a few of the pursuing orcs think of going around to the back of the portal. While there, they can see the humans running towards them, but the humans vanish upon reaching the portal boundary, and any attacks the orcs try bounce off their side of the portal.

That's a good point, I had forgotten that movie. That one was a non-opaque portal, so the "correct" side showed the humans that they were going to Stormwind, but it was transparent on the other side. It also became a minor plot point, as when the portal closed, the remaining humans were surrounded.

[Millstone85]

I'm fairly sure there was a Stargate episode where people were killing themselves by diving into the "wrong" side of the titular Stargate... I believe it's the one when they're trapped on the Prison planet?

I used to be a big fan of Stargate SG-1. Probably would be again if I rewatched the episodes. And I could swear it works like this:

A|B

C|D

If you enter through A, you will end up in D.
If you enter through B, C or D, you are permanently disintegrated.

But I can't remember when that was explained.

[Grey_Wolf_c]

I used to be a big fan of Stargate SG-1. Probably would be again if I rewatched the episodes. And I could swear it works like this:

A|B

C|D

If you enter through A, you will end up in D.
If you enter through B, C or D, you are permanently disintegrated.

But I can't remember when that was explained.

Early on in SG-1 it is established that the portal has a buffering process that first makes sure "all" of you has entered. The information is then sent forward via FTL to the other side, where a reverse buffering happens and you are re-created. Therefore, the gate is one-way only. To go the other way, you need to turn it off, and reconnect from the other end.

I don't think it is ever explained what happens if you try to enter through B, but at a guess, I'd say that you'd be buffered and spit out D anyway.

As far as I remember, C and D are non-interactable. If the initial woosh doesn't kill you, it's just an energy field.

GW

[Durkoala]

But what happens if you step through? It seems like you would be bisected. The parts that went past first would no longer be in contact with the parts that hadn't gone past yet, instead they would be in contact with the other side of the portal

I'm not sure, since nobody actually tries it, but the impression I got was that the Subtle Knife's portals only existed in one direction in each dimension. If you approached it from the back the portal simply didn't exist.

[Lord Joeltion]

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SHUDAPANTAKEMYMONEY! I.O.U. a meme

I don't think that kind of portals are "possible" under our knowledge of physics. "Wormholes" are called like that not because they are literally flat holes floating in space, it's because they punch a hole in the space-time continuum.

I think our mind is unable to grasp what a real life wormhole would actually look like, but if I had to attempt a wild-guess, I'm almost certain it wouldn't look anything like a window floating by itself. It should look more like a distortion in space, a constant shuffling and bending of our perceptions towards the unknowable*. Any "Portal-like" depiction of... well... space-portals; is strictly an artistic licence, since it breaks too many more physics than any demon I know of.

Either that, or a wizard did it, of course.

*Think of the way people wizards teleport in Harry Potter (by swirling upon themselves); and imagine that such a distortion in space is hanging about a meter in front of you. It will always look towards you, because AFIK, wormholes should be omnidirectional. That doesn't mean they are spheres, wormholes, per definition, shouldn't have any type of "shape", because they aren't tangible things (like... any kind of hole; a hole is a concept**, like numbers).

**If you doubt me, try digging a hole on your backyard and then take it back inside your home

[Yora]

Of course the best solution is to have spherical portals that don't have a back or edges

Interstellar has a spherical wormhole and it looks reallt cool. Not only is it a sphere, it is also fully transparent.

[DigoDragon]

I'm almost certain I've encountered some form of media (probably a video game..?) where you can see the 'wrong' side of the portal, since I actually had a knee-jerk response to the question- i.e. that the 'wrong' side is just a blank whirling mass of energy the same colour as the portal border that acts as a wall- but I couldn't even guess where it was that I saw that. Huh.

I want to say that the pilot episode of the old tv show Sliders panned the camera around to show you the backside of the portal-like wormhole that gets created. I remember it being something like a wavy effect you'd see on a disturbed pond, but I can't find reference images to confirm it. I don't recall the show explaining what happens if you try to touch the back side.

[Anonymouswizard]

SHUDAPANTAKEMYMONEY! I.O.U. a meme

I don't think that kind of portals are "possible" under our knowledge of physics. "Wormholes" are called like that not because they are literally flat holes floating in space, it's because they punch a hole in the space-time continuum.

I think our mind is unable to grasp what a real life wormhole would actually look like, but if I had to attempt a wild-guess, I'm almost certain it wouldn't look anything like a window floating by itself. It should look more like a distortion in space, a constant shuffling and bending of our perceptions towards the unknowable*. Any "Portal-like" depiction of... well... space-portals; is strictly an artistic licence, since it breaks too many more physics than any demon I know of.

Either that, or a wizard did it, of course.

*Think of the way people wizards teleport in Harry Potter (by swirling upon themselves); and imagine that such a distortion in space is hanging about a meter in front of you. It will always look towards you, because AFIK, wormholes should be omnidirectional. That doesn't mean they are spheres, wormholes, per definition, shouldn't have any type of "shape", because they aren't tangible things (like... any kind of hole; a hole is a concept**, like numbers).

**If you doubt me, try digging a hole on your backyard and then take it back inside your home

I mean, I set it up completely as 'a wizard did it' because nobody knows what a real life wormhole looks like. In general I only like 'flat' wormholes if there's some kind of 'frame', otherwise I like my wormholes/portals spherical or otherwise shaped (which is only important when we're trying to transport something through it).

Honestly, I used wormhole because it fit with the entire 'scientific sorcery' shtick, and I was trying to get most types into a single post.

Interstellar has a spherical wormhole and it looks reallt cool. Not only is it a sphere, it is also fully transparent.

Oh yeah, although my favourite are Night's Dawn Adamist Wormholes. Spherical, black event horizon, last for a fraction of a second (not that it matters), turns anything touching the event horizon into energy, transports whatever's inside. Edenist wormholes haven't been fully detailed at the point I am (70% through The Neutronium Alchemist) beyond that voidhawks fly into them, so I think of them as being vague spheres connected to the white wormhole space which is connected to the end point.

[Frozen_Feet]

The back of a portal usually looks like the surrounding environment, sometimes distorted as if by a lensing effect because light is curving along the edge. This may change if the primary source of light is partly or directly in front of the portal. In such cases, the back looks like a black patch or shadow as light is going into the portal instead of meeting your eye. On the other hand, if the primary source of light is behind the portal, the back is almost invisible as light follow a curved path along its surface.

If you try to approach a portal from the back, you will slide along the back edge untill you end up in the front. If the portal is smaller than you, you will visibly distort as your body is spread along the edge. In case of really small portal, when your body would be large enough to flow along both edges, it will appear as if a hole or tunnel is pressed through your body. In such cases it is inadvisable to continue, because if you do your body will wrap around the portal and may be twisted into unrecognizable shape or be torn apart.

[leafman]

Early on in SG-1 it is established that the portal has a buffering process that first makes sure "all" of you has entered. The information is then sent forward via FTL to the other side, where a reverse buffering happens and you are re-created. Therefore, the gate is one-way only. To go the other way, you need to turn it off, and reconnect from the other end.

I don't think it is ever explained what happens if you try to enter through B, but at a guess, I'd say that you'd be buffered and spit out D anyway.

As far as I remember, C and D are non-interactable. If the initial woosh doesn't kill you, it's just an energy field.

GW

The back side of the open gate would supposedly give anyone trying to pass through a really bad day according to Bra'Tac. The "woosh" would destroy matter. It was used to destroy a bomb, part of a Jaffa funeral service, and to clear ice in front of the Antarctic gate. The iris was close enough to the event horizon that it was able to stop the unstable vortex from forming.

Source: http://stargate.wikia.com/wiki/Starg...specifications

[KillianHawkeye]

I'm fairly sure there was a Stargate episode where people were killing themselves by diving into the "wrong" side of the titular Stargate... I believe it's the one when they're trapped on the Prison planet?

IIRC, the prisoners were actually just standing too close to it so that they be killed by the initial "woosh" of the opening Stargate, and I can't remember if they knew it would kill them or not. I don't believe anyone ever tried entering a Stargate from the back side in any of the shows.

It's been quite a while, though, so I might be remembering wrong.

[Psyren]

the backside of the portal is just as a valid part of it as the front to enter, you just exist from the back of the other portal as well.

This is what I go with, and since there's no real narrative importance to doing so most of the time, it just never comes up.

[Bohandas]

the backside of the portal is just as a valid part of it as the front to enter, you just exist from the back of the other portal as well.

The real problem is the edges of an unfraned 2d portal, which seem to me like they ought to cut anything that touches them to ribbons

[Rodin]

The real problem is the edges of an unfraned 2d portal, which seem to me like they ought to cut anything that touches them to ribbons

Which is indeed the case for portals in the Wheel of Time, to the point where they eventually get deliberately weaponized by opening the portals inside people and even sending them skimming across the battlefield opening and closing to reduce large numbers of enemies into chunky salsa.

[Psyren]

To avoid the" microfilament slashing portals" issue, I would have the edges repel matter, like a much stronger version of attempting to make two identical magnetic poles touch. For most people and objects trying to touch a portal - or standing in the area where one opens - the portal will simply push them away. If however a sufficiently powerful force/weight tries to touch a portal, or a sufficiently dense solid object is in the way of an opening one, or there is insufficient space to open one in the chosen destination, the portal itself will simply collapse/fail. This method will give you a "safe" means of opening portals, one that would prevent them from being weaponized.

I'm uncertain which version the Doctor Strange portals use.

[Frozen_Feet]

The real problem is the edges of an unfraned 2d portal, which seem to me like they ought to cut anything that touches them to ribbons

They aren't necessarilt edges at all, but changes in topology of space. As result, your topology is not threatened by them, you simply slide to one side.

[Psyren]

They aren't necessarilt edges at all, but changes in topology of space. As result, your topology is not threatened by them, you simply slide to one side.

That's a much cooler/succinct summary of what I was getting at