The Portal Paradox
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- Опубліковано 27 чер 2019
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This video is about the Portal Paradox - a paradox in the video game Portal (and Portal 2) regarding whether or not a companion cube passing through a moving portal plops out of the other end with no speed (velocity, momentum), or shoots out at high speed. It’s a question of conservation of momentum, relativity of velocities, wormholes, 3D printers and quantum teleportation, glitches, and more.
REFERENCES
Conservation of momentum
en.wikipedia.org/wiki/Momentu...
Principle of Locality
en.wikipedia.org/wiki/Princip...
UA-cam video of testing the Portal 2 game engine on the portal Paradox • Portal 2 - Moving Port...
Tutorial for how to program the Portal portals on your own: www.gamasutra.com/view/featur...
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1: Put two portals on ceiling
2: Put a cube half way through
3: Gravity pulls on both sides equally therefore the cube doesn't fall
4: Profit
You would need to *perfectly* line it up though.
At this point it depends if the cup is half full or half empty
@@colingreen1006 that too it should have uniform distribution of mass
Umm you tried to out think the channel that is about physics so for that a sitting cat cannot sit
That is actually a very good thought experiment. Kudos.
There's only one way to address this issue: _Portal 3._
_Which in itself will cause a paradox because Valve don't count to three._
But half life three is coming out
What is they prank us and cancel it on the day that it’s supposed to be released on
STOP! you almost triggered the energy black hole that operates at the higgs field
They count to Alyx instead
Maybe it will not be half life 3 but half of 3 life, so that is half life 1.5.
my physics teacher (slightly suggested by me since we were both gamers and I was the one who provided him a copy of the game to play) used Portals related lessons several times to explain concept like inertia or the meaning of accumulated and static momentum
He used this problem in one of his lessons, and was the funniest one imho, since the class was very interested in this problem and came up with a lot of solutions for both option A and B
how can it be anything but A if no forces are applied to the cube other than the gravitational force of the planet that changes when cube comes out of the other end resulting in it just ploping out?
@@user-ft8uk3xo7lyess!! Im thinking the same thing. If nothing but gravity is moving the box why would it fling up like that
@@zRuSh_XraYbecause as layer of the cube come out of the blue portal they will push the layer before them out as fast as new layers are forming which is the same as the orange portal’s speed. The orange portal makes the most scenes as the reference frame (thing the speed is measured based on) because the environment does not even need to be there for the experiment.
@@bigshot103 with that logic… if a door flies past me standing still… i get launched at supersonic speeds fo no reason…? Cus thats the pov of the box. Nothing makes the box move since nothing is aplying any force to it. (Exept gravity ofc, hence the flop)
@@zRuSh_XraY
You’re missing the part where the rest of the world behind the door is also moving towards you in the case of portals. Your analogy doesn’t work because you’re only accounting for the door. If a portal is approaching you, the REST OF THE UNIVERSE behind the portal is also “approaching you.” A normal door does not “take” everything else with it, portals do.
if a portal in this game's rules, as I have understood, is in a surface and it starts moving, the portal disappear instantly
except in one level of portal 2. where you can place in a moving surface when ||you and wheatley are cutting the neurotoxin supply|| although there is no way for the player to enter the portal
you can enable movable portals in console
@@marengo6990 how?
@@marengo6990 necc
@@ajgumpper necc
"Speedy thing goes in, speedy thing comes out."
Unrated comment
Speedy portal sucks something in shoots like cannon
But the cube isn't moving relative to the exit so it shouldn't be moving relatively when it comes out
@@crazynachos4230 but thats the thing the portal gives the energy to the cube shooting it out of the outside like a cannon
@@warpedmine9682 that's not how physics works tho, there is no force being applied to the cube, which means it cannot acquire velocity by Newton's first law. The Portal doesn't apply force, it's just a hole in space. The result would be the same as if the portal was just a wall with a hole in it.
I think this paradox is the entire reason that Valve implemented a "no portal on moving platforms" policy except for one exception where it would be impossible to put an object through it
That just opens up another problem: What do they mean by "not moving"? How is a reference frame chosen and with what justification?
Also, aren't there two exceptions? The one where you shoot it onto the moving platform and the one where you shoot it on the moon which I'm pretty sure is not stationary with respect to earth.
just go into the console and enable that
Well this and it also the programming headaches.
No that's not right.
At the end you open a portal on the moon and it works. And the moon is moving damn fast.
@@SuperDeinVadda Don't forget the moving panels in the neurotoxin generator scene.
The player was prohibited from ever placing moving portals in any situation where they could be interacted with directly. That doesn't mean they can't canonically be moving.
Years ago, I was trying to program a small 2-D platformer game that had a mechanic where a user exiting one side of the screen would reappear on the opposite side (same with top to bottom). I tried adding an extra mechanic where the user could resize the game frame to solve puzzles and I ran into this same question. I realized that I had accidentally backed into creating a Portal style game in 2D with moving portals. In terms of physics, the proper answer is that the object leavers the exit portal with the speed and acceleration it had RELATIVE to the entrance portal. And that speed and acceleration is relative to the exit portal (not the environment). While it makes for an interesting thought experiment, it creates a lot of problems for a programmer. For example, if the user is shrinking the game frame, the portals are moving toward each other. An object entering a portal gets a speed boost from both the entrance AND the exit portals (because they are moving toward each other). If a user allows the player to go through the portal several times while shrinking the screen, the user will accelerate each time, until the player is going so fast that the frame rate of the program can't keep up. This creates weird problems with the collision engine (player is moving so fast they pass straight through solid objects) and the rendering engine (player is moving so fast that it creates an optical illusion where it looks like they are moving backward). After breaking my brain on this for a while, I realized why portals really aren't allowed to move - it creates physical possibilities that are impossible to replicate with a computer. I ended up abandoning the project because the physics was not something that could be simulated with a computer. I'm guessing that the developers of Portal had these same issues, which is why the portals can't be placed on moving surfaces.
Do you have any published games that I can play? I want to see what kind of games you’ve made 😊
There's already a game similar to what you're describing, about wrapping around the screen edges. Look up "Four Sided Famtasy". I got 100% completion on it. Enjoy ...
You could always try to dampen any speed above the maximum natural speed that your character can attain by themselves without portals and call it simulated wind resistance.
Consider what you would see looking into the exit portal. You would essentially see the ground pushing the cube out of it. When you think about it like that, it seems like it would have to be relative to the object and the entry portal.
I'd think of it like slamming down a ring around a wooden cube. Except the ring is now in two seperate places. Box go plop
@@SkyeBerryJam in the ring plopping down scenario The exit portal is moving opposite of the object exiting it canceling out the momentum. Imagine you have your exit portal on a wall and you're standing right next to it. Looking into it. The entrance portal is coming down at the box very fast so what you see is the box coming at you very fast. The box goes through the portal slams into you and sends you flying. Speedy thing go in. Speedy thing come out. It doesn't matter that everything else on the other side of the portal was stationary in reference to the box or the none of it went through the portal. The box was speedy going in so it must be speedy coming out. When a portal is moving literally everything is speedy relative to the portal.
@@ahrengroesch8774 I mean if we want to get really technical I think none of these things happen and we need to know how objects interact with the edge of portals/how gravity works for something with its two halves on opposite ends of a portal
@@SkyeBerryJam I am dying for someone to get technical with me on the topic of portal thought experiments. On interactions with the edges of portals, I lean towards it working effectively like it's just a plain hole in a flat surface. I see a portal less as teleporting something that goes through it, and more like creating a normal man sized hole in a wall/ceiling/floor that has another universe on the other side of it that is also the same universe from a different direction. I think you could grab the inside edge of a portal just like you could stick your hand through and hold onto a hole in anything.
On gravity, it being described as the bending of space time, and a portal seeming to be connected tears in space time, I lean towards gravity from either side stopping at the portal. Thus if you were half way through it you would be pulled or pushed in both directions. So if both portals were on the floor you could float there feeling pressure in the middle of yourself. Or if both were on a ceiling it would feel like you were being pulled in two. I believe this is a plausible explanation explain of the behavior observed in the game.
If you think none of the video's or my explanations thus far is how it would work I'm dying to know your ideas.
Okay but what you see and what is happening are not the same thing.
Aperture Science wants to remind you, that you can't put Portals on moving walls.
Thanks.
Edit: "Could you guys stop commenting the same stuff on my two year old comment."
Daniel Kröber I was looking for this comment xD it's been a very long while since I played the game, but I remember you are told it's not possible to place portals on moving surfaces, and if the surface with a portal starts moving the portal just fades
He referenced this in 0:55 . He is under the assumption "what if we can put it on a moving platform"
Except for that part near the end of Portal 2 where you put a portal in a moving surface?
@@GoudaBug right, the section where you had to cut the neurotoxin tubes with the lasers. Sadly, there's no way to actually go through the portals without console commands, but I'd assume it would be the same result as the portal moving down: no physical objects allowed.
What if the portal was a machine and was just pushed?
"The portals never move"
*Cough cough* neurotoxin generator *cough cough*
Very true
Exactly.
Yeah but that's kinda the game's fault at this point
True, but the entry point is stationary, and only the exit point moves. It doesn't create the same paradox, since entry and exit are different when thjnking about the paradox
@@TheSpyroplayer Now that I think about it, you are right. The entry portal is still, and the exit portal is moving, but the thing moving through the portals is light; a laser. Light always travels at C.
Assuming that portals are only windows as seen in the games, the only force applied on the cube to move him is the gravity force at any speed of the orange portal
The portal, in my opinion, would behave as if the bottom platform was pushing it into the portal, since the platform moving towards the portal, and the portal moving towards the platform are essentially the same thing in this context.
no they are not. if drop a tube on the ball it would not be launce up into the tube. if you however slam the ball into the tube it would. its not essentailly the same at all.
@@erikcarl2384 what
I need context here, what tube, and what ball?
@@SleepyFunkin any tube and any ball that fits into a tube. you dont need any context.
@@erikcarl2384 No, it is. You're assuming there's a surface the ball is sitting on. Physically speaking, if you move a tube over a ball floating in space, such that the ball goes through the tube, it's the same thing as moving the ball through a stationary floating tube.
This is the main principle behind the theory of special relativity. The common example provided for this, is an elevator floating in space with you inside of it.
You feel yourself being pulled to the bottom of the elevator at an acceleration of 10m/s^2. You cannot see outside the elevator. You are tasked with discerning which of the following is true:
a) You are inside an elevator that is accelerating upwards; or
b) You are inside a stationary elevator that is near a massive body, and are thus experiencing a gravitational pull
Which is it? You actually can't tell.
If the elevator were to accelerate upwards at a constant rate-let's say 10m/s^2-you would feel the elevator pushing up against you with a force proportional to that acceleration (due to F=ma). If there were a gravitational field, perhaps that of a planet nearby (but invisible to you since you are inside the elevator), pulling you down at a rate of 10m/s^2, and if the elevator were stationary in this case, you'd likewise feel the elevator pushing up on you with the same force.
Einstein's theory basically says that, no, there is no way of differentiating these two scenarios:
"The laws of physics are invariant (identical) in all inertial frames of reference."
The thing is that reactionary forces only applies to objects that COLLIDE with eachother. If there was no portal, then yes the cube getting hit by the wall and the wall getting hit by the cube would be the same, but since the cube doesn't collide with anything, it simply goes through the portal unaffected, and thus does not react to anything.
I rule in favour of Option D. When the stationary object is consumed by the portal, the source engine crashes.
the entire universe is running on source engine.
No no, it’s option *3* .
@@hiu2ying *critical error*
You call d the teir zoo route or else
Option E: Portal crashes to desktop and a pop-up with the secret download link for portal 3 is shown
To quote GLaDOS from Test chamber 10, "Momentum, a function of mass and velocity, is conserved between portals. In layman's terms: speedy thing goes in, speedy thing comes out."
So what happens when a stationary thing goes in? A stationary thing can't come out
@@trash9378 yes it can. Replace the term portal with hole. The hole is in motion, not the box. the hole is being pushed down around the box. Only external forces on the other side cause it to fall over.
Option A is the correct one by any means, I don't know why would anyone even question that, portals are just a continuation of certain space in one place on another place, they only transfer the existing mass and energy as a continuation of space, they are not some energy generating force.
@@trash9378 The answer is "Momentum, a function of mass and velocity, is conserved between portals. In layman's terms:stationary thing doesn't go in because it's stationary! Stationary things can't go."
@@cyraknoss Technically the velocity being measured is the velocity at which the object enters the portal. Although the object may seem stationary to you, to the portal it is moving toward it at a rate of distance over time. Think of it as you riding a train. You are stationary, however, you also maintain the velocity of that train.
I think we could measure speed relative to the environment and still have B happen in a game if the teleportation takes both the object and portal's speed relative to each other into account. For instance, if cube and orange are both moving towards each other at a speed of 1, then cube exits blue at a speed of 2, but if both are moving in the same direction, then if orange is faster than cube, then cube would exit blue at the speed of orange - cube. The same thing would then apply to the speed of blue relative to cube. If blue is moving forward, then cube exits at its new velocity plus that of blue.
You just described the option, where the speed is measured relative to the portal. You described what would happen if the speed is measured from the cube in relation to the portal, not in relation to the environment...
If the cube is now has velo of 2 but blue portal still has velo of 1, then the gross momentum of the system is now 3 units where it was 2 units before entering the portal.
@@venomo2868 yes, and that breaks the universe and your cube may become dark matter
Portals do not affect inertia, the cube would not gain speed nor would it move in either scenario.
@@Izzmonster until more than half of it is out of the exit portal, then gravity would pull it over onto the ground.
I know this is a super common comment, but I wanted to put it in my own words anyway. While these “Portal Paradox” videos are very cool (and you go a great job making them!), the answer is A., it wouldn’t shoot out, because there’s no momentum being transferred between the portal and the object. The portals don’t have any properties of their own, they’re simply a window connecting two points in space. When an object with rapid downward motion falls through one portal, that is translated to the same momentum but aimed forward when launching out of a cortical portal. Speedy thing go in, speedy thing go out, so to speak. The portals don’t transfer momentum *to* the object to launch it, all that work is dont by *gravity*, as gravity builds the downward speed and that speed is then spent on forward momentum when gravity’s pull shifts. The puzzle mentioned at the end is similarly moot when you apply the actually facts of the Aperture Science portals, as if the cube drops through the stationary portal it shoots straight up, as it only had vertical momentum. If it drops straight down through the moving portal, it still goes straight up because *it only had vertical momentum.* The only variable is if the movement of the orange portal cause the cube to hit the edge, as that would cause a spin when it pops out the other side, but that’s an unnecessary inclusion as the question is about unhindered momentum.
*_"When an object with rapid downward motion falls through one portal, that is translated to the same momentum but aimed forward when launching out of a cortical portal"_*
That change in direction is a change in momentum. Direction is a part of momentum so changing direction is changing momentum. In other words a major part of A's argument, that portals do not change an object's momentum isn't actually true.
You may say that it still means the momentum only changes in direction, but that's the other thing. The claim that momentum only changed in direction is only ever going to be true in a single reference frame. A change in momentum in only direction means a change in magnitude in every other reference frame.
Meaning when you make the claim that portals only change momentum in direction you are reliant on using a single reference frame and there has to be a reason for which reference frame that is. And normally that reason is that it's the reference frame where both ends of the portal are stationary.
However that's the problem, because by saying that portals only alter momentum by direction, specifically in the reference frame decided by the state of motion of the portals you are saying the motion of the portals are actually significant to how they alter the momentum of objects passing through them. Which is the very thing you are trying to argue isn't the case.
the object has momentum relative to the moving portal
The simple correct answer from physics point of view is... such a portal can't exist at all, since according to theory of relativety information can't be transferred faster than speed of light... and all people here basically are just trying to find a way to cheat Einstein's law, which is impossible provided that we understand physics laws correctly. And if we don't... well, we have nothing else to work with anyway, so we either stuck with theory of relativety or have to wait for new information before we can discuss the subject further.
My science teacher used portal as an example to explain this and he played it for us as well which is super surprising
I want that person as my teacher
Fucking legend
Good teachers are the ones who've realized the indelible impact of well made UA-cam videos. Thankfully my teachers understood that back in my days and showed us episodes of Reading Rainbow and Bill Nye the Science Guy in class.
Great teacher.
Which part or game
I feel like Henry just tackled this century-old paradox because he just bought it from the Steam Summer Sale lmao
Gaben is pleased
Steam sales pushing educational technology since...
I bought it yesterday :)
@@skeletonrowdie1768 Playstation VR Convenience Store Simulator Demonstration?
What about one portal moving into the the other end??
You remember that game, hole in the wall? The things passing through the holes didn't push the objects unless they clipped the side of it. The way this boils down in terms of portals is simple.
1. The portal is moving down, meaning it presses into the ground which moves the location but adds 0 velocity
2. The portal is moving sideways, and since it can't be an open shape the bottom of the portal, however small, pushes against the object. With a small enough gap between the edge of the portal and the ground, the object would be picked up slightly since it's easier to lift up then be pushed.
i have watched this video a dozen times in the past 3 years and my answer changes every single time
"speedy thing goes in, speedy thing comes out"
but what if speedy thing was never speedy?
[queue vsauce music]
what if, instead, stationary thing goes in speedy hole: does it come out the other fast or slow?
Everything is speedy relative to something else. If the object exits at the same velocity relative to the ground, it would not exit at all. If the object exits slower than the velocity that the portal moves towards it, the object would compress. If the object passes through the speedy portal and its spacial dimensions do not change, than the object must be speedy.
@@CmdrShepard1001 i’m speedy relative to your mom
@@deffinatalee7699 lmao legend
Somewhere in the middle becuase the inertias would start to build on one side of the cube while the other is still moving relatively slow
slow. imagine istead of a portal it's just a hole. portals are like holes that defy euclidean space.
Everyone should play portal once in their life. Such a great game
Not on console sadly
@@kiven_gamez4474 ...why not? Ive played portal 1 on 360 and portal two on both console and PC. They seemed great except you can't play the costume maps on console (that's how it was 7+ years ago, things may have changed)
*at least once . ?
Kiven_Gamez I play 1 and 2 on Xbox 1 bruh 🤣 what world you live in?
I've played portal 2 at least 30 times
I always thought of the portals as gates or doors. Normally stationary you walk through one side come out the other. If a door frame is throw thrown at you yourself won't gain any momentum from that. Also my problem with B is, you don't have any momentum to start with even if a portal is moving at you fast and slams down on top of you you should still be standing on the same ground so what force will pull you up.
Except in your analogy, both portals would essentially be moving, not just one of them. If you throw a door frame (entry and exit), you're throwing both portals (entry and exit). But in this conundrum, only one of the portals is moving. So how are you gonna throw only one side of a door frame?
The correct answer is B.
@@Athinira I can see where you are coming from but that's not quite how I see it. I just have a hard time seeing how the portals are impeding a force on the object. I see a port as infinitely thin if some goes in one side it comes out the other maintaining its own momentum. So If you go through a portal that's coming at you rapidly it would act just as if you walked through the portal and came out the other side. I'd love to make a video on it to better explain my point of view.
@@edbproductions Let me put up a scenario for you then.
Imagine that you have the Orange portal on a moveable ceiling (that is, the portal is facing downwards).
Imagine you have the blue portal on the floor (facing up).
Now, imagine that you are halfway through the portal. Your lower body (waist down) is on the orange portal side, standing on the floor below the orange portal on that ceiling. Your upper body is sticking out of the blue portal on the floor.
Suddenly the moveable ceiling with the orange portal slams down to the floor fast, bringing your whole body through the orange portal so you're now fully on the side of the blue portal. What is going to happen?
Well, initially, your upper body has no momentum. It's just stationarily sticking out of the floor. But once the orange portal comes down, your upper body needs to move up to make room for your legs coming through the portal (assuming that the force the ceiling smahes with isn't enough to just crush your legs).
However, moving requires momentum. To move anything, momentum has to be build. Therefore, once the orange portal touches your floor, this entire time, the lower part of your body on the orange portal side has been pushing the parts of your body that has already passed through the portal. Pushing builds momentum, just like if i pushed you in real life. So once the orange portal touches the floor and stops, your body will continue and do a small jump.
The thing people get wrong here is the transfer of power. Usually people would assume that there is no transfer of power, therefore there can be no momentum. There is however a transfer of power. The power in this case just doesn't come from the floor you're standing on, but rather from the moveable ceiling with the portal. Since the ceiling is moving, it has momentum. And it's that momentum (rather than the momentum from a stationary floor or platform) that is transferred to your body.
@@Athinira ok I've been absolutely spiraling for like an hour thinking about different references planes, portal orientation, 1 portal moving 1 not, both portal moving, moving in the same direction moving in opposite directions..... Etc. Honestly at the end of it all I feel like both of our arguments have equal standings. Because here's one counter argument for gaining from a portal like in your example.
If you are standing in front of a stationary portal and the portal is going 100+mph on the other side could you physically move through your stationary portal on your side without moving at least 100+mph.
Because In my head you could poke your out and it would be moving 100+mph and your feet would still be stationary.
@@edbproductions Yes, that's exactly what would happen. Your two body parts would be moving at different speeds.
Imagine this scenario: You're standing stationary in front of a statinary orange portal. You poke your hand through. The other side of the portal (blue) is moving sideways at 100 kph (sorry, I'm european - no mph 😉 ) in a completely wind-still environment.
Would you feel the air brush against your hand even though there's no wind? Of course, because since the portal is moving 100 kmh, so is your hand. That makes it a 100 kmh difference between the wind speed and your hand, even if the rest of your body is standing still. For the air to brush against your hand, there HAS to be a difference of speed between air and hand - even if it _appears_ from the side you're standing at that it's the wind blowing.
So imagine something else: You're standing in front of a stationary portal. On the other side is a portal moving at 100 kph towards a floor. You poke just the front of your head through the portal and see the floor zooming towards your head. Would the floor smash your head once the portal reaches it, even though the floor is technically stationary? What if you didn't put your head through the portal, but the floor had a spear sticking out that would eventually enter the portal and hit you on the other side. Would it impale you through the portal, even though it's stationary? The answer is obviously: Yes.
another option is that if an entry portal moves then the exist portal has to move at the same speed. So the speed should be relative from the portal to the object itself, I think of portals like tubes or rings which are the same, the only difference is what is bigger the length or the diameter.
Portal right now costs 0,81€ on steam. This can't be a coincidence.
RiꜱᴇnHᴇᴇd 1$=0.81€
I think it is. Cause we have Summer Sale. And Valve gives good offs of their products.
It's Steam Summer Sale. Valve always makes their games dirt cheap during this time.
TBH Valve has frequently given Portal (1) away for free several times. But I'm guessing by "not a coincidence" you mean to imply that the sale is what brought it to the top of Minute Physics' mind.
Great games for cheap prices...
The portals aren't teleportation. It's just making a continuous space where there normally isn't one, it's no more teleportation than you walking into your kitchen.
Then wtf is teleportation
That's why I imagine it as A. If blue portal was on a wall, and orange portal was above you moving down wards, you would be half in one portal and half in the other. Legs would be glued to the floor due to gravity until enough of your weight was through the blue portal and then you'd fall to the floor there. From the perspective of blue portal, it would look like the floor you are on is the part moving, moving up and putting you through. It wouldn't behave any different than a doorway moving past you when you're standing still, you just have to factor how you'll be impacted by different gravity on different parts of your body.
Teleportation is Half-Lifes thing. It is used to move to point a between dimensions to move to point b. It is brought back in 2 where they manages to just sling past Xen and just telelport, but it takes some time and I am sure it Deatamizes you in one space and Reatamizes you in another.
Portals'... portal's are just tears in space time or a small form a time travel as in Portal 2 Cave Johnson mentions that the you in a Portal is you from another time, so don't stare at it. Also portals are like folding a piece of paper and poking a hole through it to walk through between those points. You stay as you just moving through a hole instantly. So you are you just walking through what is essential a door.
So you could imagine that the portal accelerating to you would be like a door accelerating to you. Option A is the answer.
exactly. imagine i drop a hula hoop around someone, they pass right through it. the fact that one side of the hoop is on the other side of the room is completely irrelevant.
There is a fourth option for the question at the end of the video - it comes straight up, but its "layers" are displaced relative to each other [so the object has a shear distortion]
Yeah, this was my thought. That companion cube is now a companion parallelogram.
For some reason this made me think of the portals like slinky's. And I'm just imagining moving the portal onto a stationary object the sane as dropping one end of a slinky over a stationary object. Now I'm wondering what the environment inside of the portals is like. I'm sure none of this would match up with theories of wormholes, teleporters, or quantum tunneling larfe scale objects but my brain went there
0:16 the technical term is "Speedy thing goes in, speedy thing comes out,"
Exactly, and in order for something to enter a portal, it must have some relative movement toward said portal. Whether it's the portal or the object that are in motion shouldn't matter in that respect. I'd imagine if portals like these actually did exist, they'd lead to quite a few changes in our current understanding of physics.
Aaron Yeetosaurous
yep
why did they make this video it’s obviously a
Aaron Yeetosaurous the thing is not speedy, the thing it’s going through is though. If stood on a platform and a ring was lowered down to your feet really fast would you get yote out? No.
@@robertjones6891 if you drop a slab of wood with a hole over a rubiks cube. Does the same apply?
@@kevinvu5432 both ends of the hole have opposite velocities relative to the cube so it cancels out
Minutephysics: the portal para-
Me: *Speedy Thing Goes In Speedy Thing Comes Out*
Yes, The first law of portal physics.
In layman’s terms:
But the thing isn't speedy. The things "speed" relative the environment is 0. That's the entire point of this video.
@@Arkouchie yes but relative to the Portal there is speed
Is it bad I read that in glados's voice
197 is going WILD on this paradox
My man
Actually there are moving portals in the game, you shoot one at the moon, the portal on it then moves quite dramatically with respect to the portal left on earth.
And that also proves that velocity is seen relative to the entrance portal, not environment or a combined system. :D
Minutephysics: It depends whether you think more like a programmer or more like a physicist.
Me, dual majoring physics and computer science: *Visible confusion*
I go with the B option even tho I work as a programmer
Jesus christ. You're a next level masochist. I'm having a difficult enough time just with CS
This your time, to discover your real you; my advice; follow you heart
You wanna get more confused? Imagine the portal wouldnt move at all and the moving pillar would be pushed through the entrance portal from the backside. With enough pressure anything bigger than the portal would just be cut off. But when its true that the portal doesnt move at all, it wouldnt move with the earth spinning and flying through the universe thus cutting a giant hole in the earth while the earth is moving through the portal.
Although i guess the portal cant not move since relativity or smth
Portals are just holes that happen to connect, if you cut a hole in a piece of cardboard and set a leggo in a table then slammed the cardboard with the hole onto the lego so that the lego went thru the hole would it shoot out the other end?
Moving portals should be in portal 3.
But that will never happen because valve can't count to 3.
Just remember at a gaming event Gabe said "yove killed more than 2 people but less than 4"
Like come on just say 3
Portals *can* move so long as the surface they're on is moving within the same plane, and not changing orientation. As in, not on a surface that lifts, pivots, or flips.
connor harker
Oh my god, did he actually said that?
Give me the damn link!
@@stardustcorpse It can, because the velocity is relative to the portal. If the portal flips then the object flips too. In space we measure by relativity so instead of measuring its velocity relatively to earth we measure its velocity relatively to the portal. That way it is as if the object is standing still but just surrounded by a moving gravity.
Six comments, divide by portal 2... Portal 3 confirmed!
"a portal connecting one PLACE on the wall or ceiling or floor to another (0:05)"
*_"Since Portals are merely connections to different points in space (spatial coordinates), the speed of the object is relative to points in space connected by the portal, not the portals themselves."_*
Which still means that the cube in the problem before even entering the portal is determined to be moving relative to that point in space over time.
*_"Portals are not objects. It is better to think of them as locations, albeit connected when they otherwise would not be."_*
This is splitting hairs, if you have a definable location that changes over time then you have a means with which to measure something's relative velocity. Even if the portal itself is to be argued to not be an object (or not moving) the surface the portal is consistently affixed to certainly can be.
*_"Portals don't move; they are reference frames for location and thus have no motion of their own. Any perceived movement is an optical illusion caused by the portal connecting a sequence of locations in rapid succession."_*
This is also splitting hairs, whether the portals constant change in location is to be considered movement or not it's still a measurement of significance since it's the reference frame where the two ends of the portal don't change in location where the portal will maintain an object's speed. Since by changing an object's direction of travel the portals will alter an object's speed in all other reference frames.
*_"Gravity, as illustrated in your picture."_*
The picture actually depicts a blue portal that is pointing entirely sideways. In order for gravity to be the reason the cube exits in that direction, gravity would have to have been taking it sideways.
*_"Not exactly. It's a matter of spatial geometry, but plenty of people confuse it with relativity and Newtonian physics because of the optical illusion of motion."_*
The portal's manipulation of object motion is never shown to be an illusion. Whenever they change an object's velocity by changing its direction of travel (which also means it changes the object's speed in most frames of reference) the change is always shown to be a very real change to the object's state of motion: ua-cam.com/video/ASUUN0W4_JY/v-deo.html
*_"Portals don't move, so the Cube would exit the portal according to its vector, shooting straight up."_*
Amusing observation to make about the animation in the video for that answer. It basically gets the animation wrong as the cube would have to be moving sideways going out the blue portal in order for it to line up with how it appears at the corresponding end going in. The animation basically tries to cover up that there would need to be a point where the cube's apparent motion going through the portal needs to change in order for it to shoot upwards like that, which contradicts the base intuition with portal behaviour that travelling through them should look seamless.
Hell, if the portal's manipulation of motion work as it does in the games (per-particle, as it's possible for two parts of an object to be moving in completely different directions as it's passing through the portal) then the cube shooting straight upwards would require the structure of the cube to get distorted.
@@J4hk3
"Which still means that the cube in the problem before even entering the portal is determined to be moving relative to that point in space over time."
In a real-world application, yes. The rotation of the Earth by itself would be a major factor in the motion and vector of the Cube. However, the thought experiment concerns itself only for exploring the implications of the relative motion of portals to the Cube, so I played along. The Cube is not moving relative to any coordinate in the scenario.
"This is splitting hairs, if you have a definable location that changes over time then you have a means with which to measure something's relative velocity."
Neither the portal or the coordinates connected to the portal are in motion. They have zero velocity.
"Even if the portal itself is to be argued to not be an object (or not moving) the surface the portal is consistently affixed to certainly can be"
That has no effect on the outcome.
"the two ends of the portal don't change in location where the portal will maintain an object's speed."
Space has no speed. If the cube possesses no speed relative to the space it occupies (its spatial coordinates), and those spatial coordinates has no speed relative to the coordinates on the other side of the portal, this will be maintained as the cube passes through the portal. Its speed relative to the space it occupies will remain zero, no matter what the speed that the surface of the portal is consistently affixed to is traveling at.
"The picture actually depicts a blue portal that is pointing entirely sideways. In order for gravity to be the reason the cube exits in that direction, gravity would have to have been taking it sideways."
When the cube exits the blue portal, it does so by dropping downwards with a 'plop'. Those two visual cues indicate gravity has been acting upon the cube, just as I'd described.
"Whenever they change an object's velocity by changing its direction of travel"
Neither the cube's velocity or vector are changed.
"Hell, if the portal's manipulation of motion work as it does in the games"
I never played the games, so I'll take your word for it.
@@TheInfiniteSheldon *_"The Cube is not moving relative to any coordinate in the scenario."_*
It's moving relative to the piston the orange portal is on. Which is ultimately the cube's entrance velocity into the portal.
*_"That has no effect on the outcome."_*
You were supposedly trying to argue that measuring the cube's velocity relative to the portal (calculating the entrance velocity of the cube) can't be done because the portal isn't a physical object, but the cube's motion relative to the matter the portal is affixed to produces the same intended measurement.
*_"Space has no speed. If the cube possesses no speed relative to the space it occupies (its spatial coordinates), and those spatial coordinates has no speed relative to the coordinates on the other side of the portal, this will be maintained as the cube passes through the portal. Its speed relative to the space it occupies will remain zero, no matter what the speed that the surface of the portal is consistently affixed to is traveling at."_*
Spatial coordinates are still a relative measurement, coordinate systems ultimately use something as its point of reference. And if we're going to go by a co-ordinate system that judges the cube as motionless then that's just the cube's movement relative to the earth, or whatever planet the given problem is taking place on.
What the video is trying to explain is that there is no reason for the behaviour of the portal to treat the earth's frame of reference as special. In the end, if you're claiming that the cube is motionless on exit because it was motionless on entrance, then really you're claiming that the cube's state of motion (both its speed and the direction its travelling) can never be changed by a portal. But going by established portal behaviour from the games, that isn't true.
*_"When the cube exits the blue portal, it does so by dropping downwards with a 'plop'. Those two visual cues indicate gravity has been acting upon the cube, just as I'd described."_*
Again the exit portal at 2:39 is pointing entirely sideways. The cube very clearly isn't exiting by "dropping downwards" as exiting would require a sideways motion. You were asked how the cube exits the portal, not how the cube falls on the ground. Yes there is gravity, it's clearly not the reason why the cube exits.
*_"Neither the cube's velocity or vector are changed."_*
I linked to you an actual physics professor pointing out that portals do change object velocity vectors. The portal interaction in the games show that an object's defined velocity is shown to be different before and after leaving the portal, within the same frame of reference or coordinate system. This demonstrates that going by the games that the portals can change an object's velocity and momentum.
*_"I never played the games, so I'll take your word for it."_*
Will you take my word for it that going by the games it's B then?
I get the impression that you're trying to move away from the game's depiction of portals and explain how you think that portals would actually work. This question is very much rooted in the games' depiction of how portals work (after all I doubt the notion of being able to attach portals to physical surfaces is all that realistic either) with the physics of the question being then applying that established behaviour to good physics knowledge.
You could make an argument on how you think portals would really behave while acknowledging that it contradicts the game's depiction of them. Thing is, it is still kind of necessary for portals to be able to alter the velocity/momentum of objects in order to serve as seamless passages (this video suggests this can be treated as a conservation of momentum in "a curved spacetime").
Otherwise it really does seem like you'd get the "cube flatten" result that the video talks about. In other words if the motion of matter really was unchanged on travelling through the portal (each particle on leaving the portal maintains its current state of motion, meaning they all end up at the same point). I said that the portals appear to operate per-particle in the games but that's obviously how it would work in real physics as well. Or the particles end up pushing into each other, which is just an alternate explanation for B.
@@J4hk3 “It's moving relative to the piston the orange portal is on.”
Which may have been relevant, had the narrator not introduced the additional observational frames of reference on both sides of the portal. When you account for all observational frames of reference, the piston is confirmed to be the only thing in motion.
“You were supposedly trying to argue that measuring the cube's velocity relative to the portal (calculating the entrance velocity of the cube) can't be done “
To the contrary, it can be done. I even measured the cube’s velocity relative to the portal. It’s zero.
“And if we're going to go by a co-ordinate system that judges the cube as motionless then that's just the cube's movement relative to the earth, or whatever planet the given problem is taking place on.”
In my previous comment, not only did I draw attention to the implications of the angular rotation of the Earth, I pointed out that the narrator is disinterested in accounting for these motions entirely and clarified that I am doing the same in the spirit of resolving the narrator’s so-called ‘paradox’.
“But going by established portal behaviour from the games, that isn't true.”
I am indifferent to the games.
“exiting would require a sideways motion.”
No, it would not. A portal is a distortion in spatial geometry which affects the space that the Cube occupies. The Cube is not in motion, the coordinates that it occupies merely change.
“You were asked how the cube exits the portal”
And I answered, addressing both the scenario that the narrator presented as well as the illustrations made for the video. The first question specifically was “How could a stationary object exit a stationary portal while remaining stationary?” (2:39)
My answer in my OP included ‘without gravity affecting anything, it would simply appear to be exiting when in reality the space it is occupying has become a different coordinate.’
The second question specifically was “The object would have to move, right?” (2:44)
And I answered in my OP clearly stated ‘Only if acted upon by an outside force such as gravity. Your illustration involves such a force.’ Take it up with the illustrator. The illustrator depicted motion that is only possible in the presence of gravity and I accounted for that.
“I linked to you an actual physics professor”
I don’t care what physics professors have to say about video games.
“Will you take my word for it that going by the games it's B then?”
Yes. I will accept that you are a subject matter expert on the games’ coding.
“I get the impression that you're trying to move away from the game's depiction of portals and explain how you think that portals would actually work.”
I am explaining how portals actually work. The way they would work in a game is dependent entirely on how the game is coded for its engine, and that is uninteresting to me. Explaining how they actually work resolves the so-called paradox, but the if the narrator was concerned with how the games would handle it, the narrator should confine the answer to the games’ coding.
“ it is still kind of necessary for portals to be able to alter the velocity/momentum of objects in order to serve as seamless passages “
This clearly isn’t necessary. Portals are just space and space itself exerts no forces.
“ if the motion of matter really was unchanged on travelling through the portal (each particle on leaving the portal maintains its current state of motion, meaning they all end up at the same point).”
There is no compressive force acting upon the Cube to flatten it, so its relative dimensions would be conserved.
“Or the particles end up pushing into each other”
There is no forces being applied that would result in a push. This is entirely a matter of spatial geometry. The reason you are reaching an incorrect conclusion is because you are introducing forces that do not exist in the actual scenario while overlooking observational frames of reference that were introduced by the narrator.
@@TheInfiniteSheldon *_"I don’t care what physics professors have to say about video games."_*
He's talking about the consequences of an aspect of portals you already agreed to. When you gave your answer to 4:04 you said the cube shoots straight upwards, despite having initially been dropped downwards, regardless your view on the portal moving you still recognise that portals can change the direction the cube was moving in. The professor in the video is telling you that is literally a change in velocity and momentum.
The portal changes velocity and momentum when it changes the direction something is moving within the same reference frame, this also means a change in speed when looking at the other reference frames, which is important for determining how portals will behave when they don't remain in a fixed position.
*_"Which may have been relevant, had the narrator not introduced the additional observational frames of reference on both sides of the portal. When you account for all observational frames of reference, the piston is confirmed to be the only thing in motion."_*
That's not how reference frames work. By their very nature reference frames give differing measurements for the motion of objects, if you're accounting for every frame of reference there is not going to be a definitive measurement. They are all equally true under the fact that they are all interpreting the same thing measured from different perspectives.
This means if an argument is built on the idea of finding an absolute reference frame in order to specifically disregard any other then it is not scientifically sound, especially if this absolute reference frame is one that is really just the reference frame of whatever planet the experiment is conducted on.
*_"My answer in my OP included ‘without gravity affecting anything, it would simply appear to be exiting when in reality the space it is occupying has become a different coordinate."_*
Yeah I did wonder why you were trying to argue that gravity was the reason the cube leaves the portal given that you already acknowledged that it would leave it even without gravity. The cube clearly isn't exiting a sideways facing portal by "dropping downwards". I've grasped that you're arguing that the cube hasn't actually left the portal until you think it actually moves but that's a really bizarre way of looking at it given the cube is to all intents and purposes on the other side of the portal, it's even implied to be effected by the gravity on the other side.
*_"This clearly isn’t necessary. Portals are just space and space itself exerts no forces."_*
If you think this is clear then I don't think you've grasped the problem.
Imagine you have two cubes ten metres away form each other floating in space, a portal travels (or whatever wording you are happy with) towards them and engulfs both of them, one after another.
The exiting end of the portal is also in space, completely stationary much like the exit in the problem. Do you believe that the first cube on exiting will remain in place due to its lack of velocity, so that the next cube will end up exiting into it?
I could see you arguing that the space the cube occupies keep getting moved, but that's not how you described how a "moving" portal works, which is that they are _"connecting a sequence of locations in rapid succession",_ not that they are actively shifting the "spatial coordinates" potentially massive distances beyond the exit portal.
Now, if you say the former, that the two cubes end up together due to them both exiting at the exit portal at the place and remaining there. Well apply that concept to the individual particles of a single cube. You'll basically end up with the very thing you insisted required a compressive force.
It's not that the portals themselves are necessarily creating forces, it's that even if it isn't, forces are going to naturally happen as a result of the space occupying the matter getting shifted, you already agreed to something similar happening when you acknowledge the object experiencing shifts in their relative direction of gravity on entering portals.
If you imagine the portals as infinitely short tunnels, you can expand the concept to a general case for all wormhole-like pathways.
When you slam a tube down around an object, the object doesn’t gain momentum through the tube; the motion of the object relative to the tube is entirely dependent on the tube. In this way it can be argued that case a (plopping out on the other side) is the resolution of the paradox.
On the other hand, if you consider the portal as comparable to a hand coming down around a wet bar of soap, an argument can be made for case b (object goes flying). When you grab a bar of soap, you need to exert force upon the bar as you grip it. This force commonly and easily launches the soap out of your hands, in spite of not adding any apparent momentum to the soap. The energy gained by the soap is sourced from invisible interaction between the object and the passage it travels through (in this case, the hand).
This argument, essentially, is that one cannot actually pass freely through a portal which is in motion. In order for the object to gain speed as it passes through the portal, the portal itself would need to be exerting some force on the object (otherwise the object would remain inert, according to the generalized case of a tunnel of arbitrary length).
Either a moving portal “squeezes” objects passing through due to some unseen interaction between the membrane/field of the portal and said object, or the object does not gain momentum.
Put into terms of energy, unless some unseen mechanism transfers energy from the moving portal to the object enveloped by the portal, it’s impossible for the portal to cause the object to accelerate.
Yet another example would be jumping through a window on a moving vehicle, without touching the frame of the window, while the start and end point of the jump are both stationary from the perspective of the person jumping. The properties of the vehicle don’t matter - it could be a bullet train loaded to maximum capacity, or it could be a bike meandering through a neighborhood. From the perspective of the person jumping, all that changes is which side of the window they occupy. In order for the person to fly like a rocket out the other side of the window, the vehicle would need to transfer some kind of energy or momentum to them.
Barring some kind of novel discovery about topology or vector addition, I feel like this one isn’t toooooo hard to suss out. But then again I dropped out of college lmao
Aperture Labs uses quantum tunneling if I remember correctly whereas Black Mesa was dabbling in wormholes
Yep
@cak01vej this would obviously not be the case for wormholes, as I think you already know!
@cak01vej don't forget that portals are essentialy just doors that open elsewhere so using a portal like this would act the same way as hitting a static object on a table with a tennis racket without strings the only loophole is the laws of gravity not momentum
@cak01vej That would hurt a bit
B seems the most intuitive and so also applies to the final puzzle: object would exist at an angle.
Maybe this is why you can't have a portal on a moving object.
Yeah... I think Valve notice that it would be even more tricky to move the portals around, so they made every puzzle with static portals XD
There is one puzzle in Portal 2 that has you putting a portal on a platform that is moving vertically, so lasers can cut down a pipe. I think the dev commentary says that is the only instance in the whole game such thing happens, every other moving object (a hatch door, for example) instantly disintegrates the portal it has on.
@@geraq0 portals can only be placed on conductive surfaces. The doors aren't conductive,and aren't coated in conductive material either.
That's why you can make portals on white surfaces, because that has ground up moon rocks. The white gel is made with moon dust,which is why it makes surfaces conductive. And the ending of Portal 2 shows this as well.
@@c0ldshock927 Yes, I know that. That wasn't my point at all. I was talking about hatches activated by switches, for example, that change angles hence deleting any portal created over them.
Earth is moving.
Last question my thought is that it shoots straight out of both portals since no force is acting on the box besides gravity so it remains in a straight free fall. Unless entering the portal adds a sideways force through fantasy physics.
Keep in mind that as long as it keeps falling, the portal will move. The top face of the box will not land in the same area of the orange portal as the bottom face, and therefore will not land in the same area of the bluish one.
Not being able to go in a straight line, it would come out diagonally.
Flawed logic.
Look at the exit portal only
What happens? The box. Very quickly pops through it.
It has velocity as the top of the box goes through the portal, and then further away as the rest of it goes through.
To then free fall after would be to just delete this velocity
It doesn't matter if it's standing still before hand.
From the exits perspective its shooting through it with some velocity that has to be maintained
Portals are just sort of like portable space; the game calls them interdimensional doorways or something like that. The cube in this situation isn't moving, but rather, space is moving around the cube, if that makes any sense. It would obviously be option A. If the cube itself had velocity, i.e. it were thrown through the portal, obviously it would retain its speed relative to the environment since it's akin to just throwing an object through any old space, like a doorway.
Space moving around an object is identical to that object moving within the space, motion is relative.
*_"obviously it would retain its speed relative to the environment"_*
What's "the environment"?
There's no reason for the portals to treat earth's reference frame as special, as we see in the games portals don't even have to be placed on earth. So when you say that speed is retained relative to an environment, the only rule that would be consistent is to use the reference frame where both ends of the portal are stationary. But there isn't one in the problem.
If you go by the entrance portal's reference frame, that's the one where the cube is actually moving, which then explains how the cube can exit on the other end. Essentially the cube exits at the velocity it enters with, which sounds obvious, but the key thing is that entrance and exit velocities in inherently relative terms to the entrance and exit, including both relative speed, and relative direction.
This just requires accepting that there isn't already a reference frame where the speed gets conserved. Going by the moon scene in portal 2 though that is already the case, we outright see that Chell's speed changes when she ends up at the moon, as being at the moon means moving with the moon, which actually moves incredibly fast in orbit.
"It's a paradox, there is no answer!"
~GLaDOS, 2011
XD
I remember she said something like this when trying to beat wheatley with paradoxes.
Yes I answer yes
Wheatly 2011
True, I’ll go true
"Don't think about it. Don't think about it. Don't think about it. Don't think about it." Glados 2011
Quote by GlaDOS:
"Momentum, a function of mass and velocity, is conserved between portals.
In layman's terms, speedy thing goes in, speedy thing comes out."
conversely, if a speedy thing comes out, a speedy thing went in
Counterpoint momentum is not conserved because the direction of the object changes therefore glados is a lying pos
When neither portal is moving 👍
When one of the portals is moving with constant speed as in 0 acceleration the object passing trough orange portal experience 0 acceleration and comes out of blue portal with same speed as Orange Portal had.
What happens when you stop the portal mid point of the box? in that moment when you stop the portal instantly in place trough the object is felt two foces that pull each other one tries to stay still and other is moving 50km/h and if your human neck can with stand that kind of instant pull 😏 15 hours later while super drunk someone said "it is like hula hula rim!" and we came in to conclusion the moment you slam it to someones head and start pulling the head should be flying off in the most brutal way possible 😂
yeah but it's not "speedy portal rams into, speedy thing comes out"
@@valentinorubio703 I spend 17h drunk arguing about this topic and to sum it up: Orange Portal's speed is given to the object without acceleration.
Everything else ended up with "Well that that can't be right" and we also never agreed who of us won the argument :D perhaps we all lost.
Bro left us with more questions than the beginning
Thank you for making this video it was very cool 😎
I always thought of them as a ring that was split. Teleportation is like putting a ring around something else, but this coming out of the ring is placed different in spaces. As if it was a tunnel with the length of 0.
so A, right?
@@Lance3015 it'd still be B. From the perspective of the side of the ring the cube is leaving, it's still coming out of that side at a certain velocity relative to it, therefore that velocity would be maintained.
@@hushwonder2070 Not true, it makes no interaction with the cube itself therefore it would not carry over the velocity.
There is effectively no space; open air in-between the portal boundaries and they've never interfered with the objects passing through them like you say
@@Wert-eo7sz Maybe the portal is not moving but disappearing and reappearing at a different point in space quickly that case the object would go through you. and the laws of physics still would work.
@@Wert-eo7sz Our current understanding of the universe isn't very great...
I'm surprised you didn't mention gravity. The block sitting experiences torque as soon as it begins to pass through. It should exit the second portal with rotation.
Exactly what I thought, it wouldn't flatten, gravity would pull the heavier side of the block, the one leaving portal B, completely out of the portal.
It should fall off the second portal, right?
Kurokami Reaper It should, yes
@@Certrix, it would flatten. Since the tiny bit first teleported stays in the frame of the teleporter, it experiences gravity from the sites of both the entry and exit portals.
@@Sivah_Akash That doesn't make sense. The normal force of the ground pushing on your feet equals the force gravity is pulling you down with. You don't flatten
for me, option A is more correct. In one of the "Aperture Investment Opportunity" it was said that the portal gun creates a hole in space, which means teleportation works on creating a hole in a curved space. Such portals should be treated as doorways, and if the doorway is flying at you, then you will not get its speed when you pass through it.
You would if the exit of said doorway was in a fixed location. Leaving a stationary exit entails movement by default.
My interpretatios is like this:
You are standing on the ground in universe A. Universe B is on the other side of the portal, facing up.
The portal comes down on you at 5mph. You emerge from the floor of universe B at 5mph, driven by the floor in universe A.
You don't pop up, because universe B hits the ground of universe A once you are fully emerged. Or if it kept going, a cylinder of ground would continue to rise up out of the portal. Like using a hole saw.
Universe A and Universe B are in fact the same universe, but I think this is consistent with how the game works, and makes sense from a physics perspective. It's kind of like slamming a cup down on top of a spider to catch it. The spider enters the cup real fast, but doesn't continue heading up until it hits the base of the cup, because once the cup hits the ground, the speed of the cup quickly matches the speed of the spider.
absolutely no one:
minutephysics: lets give this old paradox that the internet has argued about for a decade another step of complexity
We definitely need to think about accelerating portals.
Its just /v/ shilling
@@luck3949 but first, let's talk about parallel universes
327likes in 1hours? I cant even get 10likes in year
You're so original
*Minutepsysics:* Let's talk about Portal Paradox which isn't actually a paradox...
*Me:* That's a nice paradox.
A portal is just a bridge between all of the points on the surface of one portal and the surface of another portal, so you could think of the entrance portal as just having the entire room that the exit portal is in copied and attached to the back of it. if you go by this logic, moving a room down onto a portal and having a cube launch out would be weird, so the cube would just plop out.
А вы преставьте порталы в качестве дверной рамки.
По сути портал это и есть дверь.
И вот представим: лежит объект на поле и на него падает дверная рамка, что произойдёт?
Дверная рамка упадёт на объект, а объект продолжит стоять на месте как не в чём не бывало.
Так почему если бросить на обьект портал, он должен вдруг из не откуда получить скорость?
Портал это дверь ведущая из одной точки в другую, ваша дверь в комнате, ведёт из комнаты в коридор, а падающая рамка на объект ведёт объект в одно и тоже место.
Но портал позволяет вам появится а другом месте с теми же характеристиками.
Если бы портал имел какое-нибудь гравитационное поле, то да, я бы поверил что вылетить из портала будет возможно, так как он вас своей гравитацией вытолкнет, но без гравитации, там нечему вас выталкивать.
According to GLaDOS in the first game: "Momentum, the function of mass and velocity, is conserved between portals. In laments terms: Speedy thing goes in, speedy thing goes out". Since the object enters the portal with zero momentum, we must assume it leaves the portal with the same momentum. Thus, the correct answer, according to GLaDOS, is option A
What the1necromancer just said in laments terms means that the speed is relative to the portals. So if portal is speedy and moving towards speedy companion cube, lets say, the same speed towards eachother, then the cube would come out at 2x the speed.
You are exactly right, I can’t believe they don’t say this in the video. The box has no kinetic energy so it cannot have kinetic energy going out of the portal
@@adamguenther190 he never said it because there was never a need to say it. Things like speed and measurement are not definite, they are relative. Meaning it is measured relatively to another object. So the cubes speed is measured relatively to the portal, meaning that if the cube and a portal were moving towards eachother at the same speed, then the cube would leave the exit portal at twice the speed.
This
The portal is basically a door
If you are not moving and a door with a door moves towards you, you will still not be moving by the time you arrive to the other side of the door
@@yaddar how many times do i have to say that speed is measured RELATIVELY.
Imagine you are walking in the same direction a train is moving, lets say you and the train were moving 3 MPH. If your speed was measured relative to the ground, you would be moving 6 MPH. If your speed was measured relatively to the train, it would be 3 MPH.
Its basically the same thing for the portal, except this time, the portal would be moving at you. Its literally what the1necromancer said.
If you are moving towards a portal which is moving towards you at the same speed, your body would go theough twice as fast as opposed to having the portal stay in the same place.
Portals don't work on moving platform... Except for that one time in the neurotoxin generator room
@Cris Angelo D.C I think that that was actually a storage unit not a generator but wheatley was kinda dumb so he thought it made it
That's what I was thinking about
So weird how it's just that one spot where it works and nowhere else
Ascaban I’m p sure u can do it in Portal 2 custom editor
@@makinbacon21 you cant. as far as i know, there is a console command that, if 'true' causes a portal to disappear if the ground they're on moves. that command always stays active, apart from that one level.
Definitely the B scenario, because if you look from the other end, you will see the cube going at you with great speed, so it will shoot out. However...what happens if the portal stops in the middle of the cube? I suppose the cube will shoot out with half of the portal velocity before it stopped. And so on.
This. On the first side of the portal the cube has no momentum, but once it moves to the other side, it does have momentum. The movement doesn't just go away, so it would have to be retained, causing it to shoot out.
It depends on why the moving portal is moving, is it falling under its own weight or is a force being applied to it?
Energy conservation says that for stationary portals the kinetic energy of the cube is maintained (speedy thing goes in, speedy thing goes out) so logically this still applies to a moving portal, the energy being used to move the portal over the stationary cube is added to the kinetic energy of the cube. If a very strong piston pushes the portal over the cube very quickly, then the cube will shoot out of the other end quickly, if the portal is falling with a weight of just a few grams over a cube that weighs much more, then only a very small force will be applied to the cube, and it will just barely plop out of the other end. In fact, if the end portal is angled upwards, then there may not be enough energy being added to the cube for it to fully emerge from the other end.
There is no paradox as long as you understand the rules as explained in the game, the paradox only seems to appear if you fail to fully understand what is going on.
All I wanted to do was play portal, not question the exsistance of universe. But I'm glad I did.
i'm glados you did oof
@@jessejordan5658 this comment is just so funny to me and i hate you for it
@@slyceth *They're
*Existence
* Capitalize “I”s
But GLaDOS already answered that. "In layman's terms: Speedy thing comes in, speedy thing comes out."
But that's for stationary portals. Moving portals would be different because their rules aren't defined in the game.
Therefore, 'Stationary thing comes in, Stationary thing comes out" #thinkinglikeaprogrammer
yes they are, portal 2 has a moving portal in the section where you cut neurotoxin pipes, and the laser exiting the portal has the same wavelength/colour as the one entering.
@@ChrisPepper1989 I read that as pro gamer
TornadoATP but the portals obey the laws of nature it exists in. And the cube has no momentum while the portal has one. This cannot be translated without adding energy to the cube.
So either the portal translates energy from the portal itself to an object. Option B.
Or its the objects momentum that matters. Option A.
All these questions are easy to answer if you always consider the reference frame to be the portal closest to the cube (or part thereof).
When you do this the calculation becomes deceptively simple;
1) calculate the forces acting on the portion of the cube still on the orange side of the portal (if any)
2) calculate the forces acting on the portion of the cube on the blue side of the portal (if any)
3) sum them to determine the total force acting upon the cube as a whole.
I cut and pasted this from a discussion on the matter in another portal paradox video...Cool concept, but I have some issue with the logic and result. I believe the output cube should be either fragmented into slices or stretched, as the portion of it that has already passed thru the portal begins moving, while the portion yet to pass thru the portal remains stationary. The transition happens quickly, however there is still a length of time when the cube is in two different states, part moving, part stationary…thus I think it would stretch during the transition. Thoughts anyone?
Of course it makes sense...you can even freeze the video when the portal "hula hoop" has only consumed half of the cube, showing half of the cube sitting stationary on the ground, while the other half is already flying out of the exit portal with motion. The only way to have part of something stationary, while the other half is moving it to stretch it. It's speculated that a similar thing happens when an object enters a blackhole....the gravity is so strong that the part closest to the blackhole accelerates faster than the part furthest from the black hole and thus the object is torn apart as different sections of it accelerate at different rates at different moments in time. The only difference here being that the cube starts out stationary, while the object approaching the blackhole is already in motion.
In reality it would stretch with the analog passing of time, but in the game, it might appear to be sliced or cut up due to the fidelity of the frame rate of the animation.
@ozmaniac33
10 minutes ago
Imagine you could watch the event in slow motion and it took 30 frames/sec and one full second for the entry portal to consume the cube, starting just before it reaches the cube. One frame later, 1/30th of the cube has exited the exit portal and has motion moving away from the stationary 29/30ths of the rest of the cube. in the next frame, the second 1/30th of the cube now has motion, but is already lagging behind the first 1/30th of the cube, but also now moving away from the remaining stationary 28/30ths of the cube. This repeats for the next 30 frames, leaving 30 slices of cube flying out of the exit portal.
2:17 and considering Valve themselves have referred to the portals as “quantum space holes” in some promos for Portal 2, this is _the way_ the portals work.
They do obey conservation of momentum like he said yet he is still drawing the conclusion b that "if fast go in fast go out"
If the cube was on a pillar, the pillar wouldnt be send flying just because a hole slammed into it. And the cube would rest on top of the pillar until the gravity on the blue side would pull harder than the gravity on the orange side
Valve: Portals can't move
Also valve: Let's use moving portals towards the end of the second games
moon rotation yes
i mean.. they must be able to move since we are all moving.
That moment is near the middle.
your logic can apply to earth too, making the portal gun useless
@@moonl1314 earth moving too)
Imo it's option A, unmoving object will still remain stationary at the exit.
Reasoning : portal is not a phisical thing, it's hole in fabric of reality, it doesn't affect object in any mean other than make it reapear elsewhere, so the only difference portal's speed would inflict upon object is that it reapeared faster, it didn't moved, it just begin to be in a new place.
Regarding example from 3:00, I find it hard to explain without image why I disagree with it, but I'll try my best :
A stationary object would reapear layer by layer, as you shown, but they wouldn't be squished, they would emerge out, but right after they would do it completely, they would stop. Object wouldn't have kinetic energy or velocity, movement would illusin made by rest of universe shifting to make space for it.
Imagine flying ball that has 0 velocity, it just is hanging in a place. If you would throw hoola-hop thrue it it wouldn't make ball faster.
Honestly, this ridle is less about logic and phisicsand more about how you understand a portal, in my reasoning why I disagree with 3.00 i explained it in a way that makes stationary portal both being and being not in motion, in example from 4:00 there are several ways cube could go out, diognally beign one of them.
Option b makes the most sense to me at first blush, but the saddest thing about portals is that they /can't/ obey conservation of energy, so it's all kind of moot. This is exemplified by the what happens when you place a portal on a floor and a portal directly above it: anything that falls through the floor effectively has infinite potential energy.
Well, if we assume that portals actively consume energy, we can satisfy conservation of energy by concluding that any energy gained by raising the cube is less than or equal to the energy lost through keeping the portals active.
In the games, the portals disappear if placed on a moving surface. Which can be explained by the logic that portals must remain at a constant distance and orientation from each other.
I don't think so. In Portal 2, when you're destroying the neurotoxin tubing, you do utilize portals that move relative to each other.
except if they are moving continously at the same speed
How about the moon portal?
In Portal 2 there is 1 moving portal
No there's moving platforms in Portal.
"In the game, the portals pretty much never move relative to the environment."
Boom. Problem solved!
Except in the one part of portal two when they changed it for the sake of a fun mini-puzzle. And also the moon
Well. Only time the portals ever move relative to their surroundings is portal 2, the neurotoxin generator.
@@link_team3855 And how do the portals work? A or B?
@@luken2o223 can't be a you would be smushed like a pancake force on an object causes another to move except in videogames, like Minecraft the speed you go when you tp, you would be dead.
Luke N2O it was moving sideways, not vertically, so some argue “you can’t move them forwards and backwards in the direction they face, so it doesn’t count!”
You could still do the test at the end of the video, however.
I never conceptualized Portals the way Stargates are (eventually) explained. Portals are physical "holes" connecting one space to another - no intelligence, no deconstruction and reconstruction on the other side. If one portal is pressed against a wall, it doesn't cause anything entering the portal to be destroyed on a subatomic level on the other side - it just means you bump into the wall at the portal's boundary.
[Stargates intelligently deconstruct any person/object entering the event horizon on one side, and reconstruct them on the other side, employing complicated tricks to (mostly) give the object the same relative orientation/speed/physical condition as when they entered, erring on the side of safety when necessary - they were, after all designed to transport people. Nothing can be partially on both sides of a Stargate pair. The major exception (which may have been by design explicitly for defense, and discovered very early by SGC) is if a barrier is placed extremely close to the event horizon, the connection can still be made and the origin gate will accept "passengers", but the receiving gate, though operating, can't reconstruct them in the space available.]
I think it would be a combination of A and B. The object is stationary, but as each portion of the object enters the portal, it is exerting a pushing force on the portion of the object on the other side of the portal. Eventually this force would be great enough to pull the object through the portal completely; essentially the object gets “sucked” into the orange portal near the end of the transition.
Option D. : When a portal move its just disappear
*cough cough* neurotoxin generator *cough cough*
@@yukkahiro ahem ahem
then portals can’t exist on earth because it’s moving via gravity
might not even exist anywhere in the universe because dark energy is funny topic
YuriNone well the neurotoxin emitter part was merely the only possible way to do said part. So you know. How else were you going to shut down the neurotoxin emitters for good
@@ethandavies7608 idk wheatley was screaming at me so i didn't really get to think
also i think i inhaled neurotoxin
‘Depends if you think like a programmer or a physicist’
But when you program video games you have to think like both 😭😭😭
Haaris Qureshi ....isn‘t this another paradox?
Not really only if you want to have realistic physics which you don’t always necessarily do
Ehhhhh not exactly.
Unless you're programming Algodoo, which is arguably a quite accurate 2D physics simulator out there (and used by academics somewhere), you're not putting real life physics equations as is in video games. Even with advanced engines like Bullet, Unreal Engine (and PhysX), or GTA V's RAGE, the physics in 3D game engine can defy real life physics, even if the code got the concept right and believable enough to percieve by our logic outside speedrunning or uncommon situations.
Besides, putting real life physics equations as it is in a game physics engine can ruin a game's fun and charm or even the gameplay itself. And performance wise, it's not good either to do those equation in 16 ms or less.
@@Xezian not really. Even if you don't use real time physics, the game itself runs on a set of rules you as a programmer input and it has to stay consistent and you have to chart your own "imaginary" physics from scratch
Bhanu Vardhan yes but programming a new set of rules is a lot easier than programming an existence that isn’t even possible yet. Physicist don’t even have the proof of concept that a portal can exist except for theories and equations, this is infinitely harder than programming a game to say when X enters A send X to B with equal momentum.
What stationary cube people are missing is that they're perceiving the cube as the fixed point in space here, when in reality you should view it as the opposite.
Portals are effectively an infinitely expandable fixed point in space, where the entrance "percieves" space at a fixed point relative to it when it's moving (despite still being a fixed point in space), and the exit has the space from the entrance moving relative to it. This is an important distinction. To the exit portal, the floor in this case is launching the cube at the same speed the entrance portal is moving. If the second portal is moving away from the direction the floor is moving relative to it, it adds to the speed of the launch, as the floor will still be coming towards it at the same relative speed no matter what the portal is doing, but it is also moving relative to the object through it. The floor effectively gains the speed of the exit portal, causing a farther launch. This is also why if you put two portals on opposide sides of a wall and move them both past the object, its effectively no different than cutting a hole in said wall.
The second the entrance portal stops is the second the cube launches. No different than a catapult. Obviously there would be some weird gravitational stuff involved as one part of the portal would be feeling gravity at a different point to the other initially, but in a space without gravity this is how it would work.
If you have it stop half way down the cube, the launch would likely be half as powerful as well, as only half of the cube is moving relative to the exit portal, while the other half is stationary relative to the entrance portal.
I think the solution to the last puzzle would be the cube come out diagonally. The way I thought about it is with replacing the cube with a pole. If you put a pole into a stationary portal that connects to another stationary portal and move the pole along the axis parallel to the portals it will move on both sides. Now imagine if you put the pole in at one far end of the moving portal, that end of the pole would emerge out of the far end of the stationary portal, and if you imagine that the pole is the correct length that its end would enter the portal in the time it takes for the portal to move its own length. that would result in the end of the pole entering the moving portal and exiting the stationary one at the opposite end of the portal than when in entered, giving both vertical and horizontal movement which means that a pole would exit diagonally, and everything should work the same way with a cube just over less length making it less noticeable
The literal term for portal is a doorway or hole between two places, if you have a moving door, your speed relative to it will stay constant
Ok but, doors and doorways aren't the same thing.
@@Doglover745 yes and a doorway is literally a portal
@@Theepic750 yes but, this is about the hypothetical kind. Which is clearly not what you're talking about.
@@Theepic750 I didn't think it was complicated, like the orange one comes down to the cube on the platform, then on the blue one you'd just have the the cube on top of the platform, with just the the cube fully thru, and then it changes to the relative gravity once thru, your literally just tossing a hoolahoop on the cube, and what sposed to go thru pops out of the other hoolahoop
Or what about if the platform the box was on is moving relative the portal speed, but the portal isn’t moving this time. It would shoot out, right?
I love that 12 years later were still talking about Portal
Altho there is no portal 3(beside bridge construction portal)
I believe that’s the answer for the final question would be:
The cube will shoot straight up but will be deformed because of the portals movement.
I think this because if the bottom of the cube starts at the centre of the Orange portal it will come out of the centre of the blue portal, however because of the movement of the Orange portal the top of the cube will go in the Orange portal at the top so will come out at the top is the blue portal.
In relativity, there is no absolute motion (as was mentioned) which means the notion that the portal is moving is exactly as valid as saying the cube is moving and the portal is stationary. Thus the behavior of a cube moving into the portal is EXACTLY the same as the portal moving towards the cube. Since we know the effect of a cube moving into a portal, we know the effect in a hypothetical 'real' world where the portal is 'in motion' would be identical.
Consider a portal that is stationary and a cube passes into it... We know the effect. Now consider that the portal is sitting on the back of a truck that is in motion and cube is stationary.... Then consider that the truck is on a rotating planet.... and so on and so on. At no point will you ever discover a fixed point. Motion is relative. The only thing that matters is the motion within the frame of reference.
Who feels like he wants to go and play portal again after watching this video
been a while might as well
I feel like I should play it for the first time!
@@PydraxAlpta me too
@@PydraxAlpta It's 90% off in the summer Steam sale right now.
YES
Physicists: Valve what will you do about moving portals?
Valve: We'll make them disappear if they move.
Physicists: Surprised Pikacu face.
Valve: makes portals move in one level anyway
@@jfb- Valve: **disables special code to do so**
@@thanosattorneyatlaw4062 Its not really special code, its the sv_allow_mobile_portals flag (accessible in console).
@@coolguy284_2 I was making it more dramatic........ It's a joke
..
Maps have a flag for enabling moving portals. In portal 2, you can enable this using the developer console. However, the Valve Developer Community site, this option causes moving portals to be non-traversable for anything but lasers.
In my opinion, Scenario A seems the less plausible.
Portals connect two points in space without creating any new space. Therefore, the time it takes for an object to enter one portal should be identical to the time it takes for the object to exit the other portal.
So, if an orange portal moves slowly towards an object, than that object should also emerge slowly from the blue portal. Similarly, if the orange portal moves toward an object at like Mach 10, then that object should theoretically exit the blue portal at an equivalent velocity. The velocity of the object relative to the portal has to be preserved so that the time between entering and exiting the portal stays consistent. If it doesn't, then where would the object momentarily exist?
Given that portals don't create new space, just connect existing spaces, the relative velocity at which an object enters a portal should dictate the velocity at which it exits. Since the object exits with a certain velocity and has mass, it would also possess momentum, thus it would result in Scenario B (or maybe C).
The only way Scenario A could work is if the portals somehow momentarily changed the mass of objects as they passed through, but that just feels like making up rules.
Thoughts?
(note i am not an expert in physics or anything so my reasoning could be wrong.)
For option B, what happens if the portal stops moving halfway across the object? Does the object get pulled through since half of it now has a velocity but the other half doesn't? Would objects get ripped apart if the speed is too high?
this is what makes me think that it'd be more like option A, it's simply a window onto another point in space, think "hole in the wall" the american game show. And regarding the issue where only part of the object goes through, then what happens to it would depend on the center of mass of the object. if the center of mass has gone through the portal, then the object is under influence of gravity at the other side of the portal, wherever that is in space.
He did a video on this and it would shoot out with half the speed or break depending on the durability of the action
Don't look at it like a portal, but like a hole in a wall with the possibility of changed gravity in the other room.
This guy gets it
@Gooey Prickles Sounds like you're overanalyzing it a bit. The way the portals function in the game is essentially like a hole and you can even put objects mid way in them. Applying real life laws to game logic is not wrong though and I'm sure you'd be right if it were real life circumstances because I won't deny that physics and motion aren't my forté, but game logic wise... It's just a hole and option A was the more reasonable explanation for the way the way portals function here. Though, real life circumstances are probably option B, if not something similar.
I get both sides but listen to this. Say that a door that transports you to another one is dropped on you and you go through, but gravity forces you to go back through. since the portal is there you go back through but you ganed no energy so it doesn't push you out. You will get stuck between them
@Gooey Prickles that is why I compare it to a magic door and you would get stuck
@@RemedieX I get what you are trying to say but it is wrong. Option b would have to have force applied to the cube in order to whoosh. But since the only force is the smasher which isn't affecting the cube it would just go through because the "portal" has no mass and doesn't realy have anything to push
Items are locally measured to the environment. As GLaDOS explains in the game, "Speedy thing goes in, speedy thing goes out"
I don't see any reason why that would imply that speeds are measured relative to the environment, rather than relative to the portal.
Non sequitur. "Speedy thing goes in, speedy thing comes out" does not mean it's measured to the environment.
So that would explain that in the HL/Portal universe that there are quantum tunnels but the portal gun shoots teleportation data
@@leonardusl5141 speedy THING goes in though. This implies for the item to go out at a velocity, IT must move.a stationary item would therefore plop out with example A.
@@digitalunity A is impossible. By the time the portal fully covers the box the box is not fully out of portal number 2. then it is in two places at once. The velocity of the box is depending on how fast it went through the portal. The box went through the portal at the speed the portal was moving therefore emerges at the speed of the portal.
C: it would shoot out of blue at a angle because the cube is traveling at x velocity downwards while the portal is moving at y velocity left . Let’s let x and y equal 3 and you have the cube moving 3 velocity downwards and 3 left, and since the portal would flip the velocities it would travel both directions at 3 velocity. (Up and right)
Also we use pythagorean theorem to solve the velocity which would be 3^2 + 3^2= c^2
9+9=c^2 18=c^2 √ 18=x x=3√ 2, so the velocity of the cube was 3√ 2 N theoretically
C=X
I'm gonna comment this before watching the video so that any conclusions there don't influence my initial conclusion:
Considering the portals are basically just the shortening of a gap between two places (like if a tunnel were squished into a door), I think of it like this: since the orange portal is moving quickly towards a solid surface, it means that the object on the surface (the cube) will pass through the portal quickly, but since the cube doesn't have any momentum itself, it just plops out the other end after the gravity changes. Imagine the cube is attached to the floor, and when the gravity changes from the orange portal pushing over it, it becomes detached from the floor and plops out. It's not actually attached to the floor of course but that's, I think, a good way of visualizing it since it achieves the same result
Portal developers were so advanced in that time that no one really understood how portals worked except them.
portals in portal were like doorframes, nothing else
@@TheWorldEnd2 Never seen a doorframe the allows you to teleport though...
@@haleph9605 Well, of course they do. You teleport from one room to another.
@@haleph9605 it is extremely localized teleportation
Jules Fontvielle
They mean that’s essentially how the portals functioned in game. You could look through them and see what was in next “room” without actually having to walk through, much like a doorway
"THIS. SENTENCE. IS. FALSE! don't think about it don't think about it"
That's the true Portal Paradox
Ehhh, true. I'll go true.
It's a paradox you moron, there is no answer!!
* confused frankenturret noises *
Yes!
OMG YESSSSS
The thing that makes me cross my arms and say "A" is: how does the cube change from still to moving without making contact with anything? For it to fly out the other side of the portal, something would need to give it energy. The moving platform doesn't touch it, the platform it's sitting on isn't moving, then would it be the portal? Since it perfectly conserves momentum, (aside from changing direction) it shouldn't add or subtract any energy, right?
What clinches it for me is shifting my thinking about what the portal does. It's not actually moving the cube, it's shifting where the cube is. Yes, a fast-moving portal will cause a cube to appear out the other side quickly, but that doesn't mean the cube is moving quickly, just that the portal's plane of "being somewhere else" is passing over it quickly. It quickly changes from gravity pulling it in one direction to gravity pulling it in the other direction.
Also, the moving platform's energy dissipates into the stationary platform.
Thanks for that final puzzle you left us with. I WANTED to sleep tonight but now…
Answer to the bonus question: If the portals were like 3D printers, the cube would come out slanted.
Oooo I like your thinking! Although if the speed is measured relative to the moving portal then while the part of the portal that prints is moving the object is also moving just the same, lining it back up again.
2+1D printers. 3s dont exist according to valve.
If the portals were like 3d printers, you wouldnt be able to see through them like in the game
2:40 the ground gets closer to the portal
The cube on the other end is affected by gravity
I imagine it like a box going through a hoop
If I drop the hoop onto the ground the cube is just in the middle and therefore on the other side of this hoop (other portal)
Actually, gravity would also be transported by the portal, so if you put one end on earth and one end in space, you would be pulled towards the portal as if it were the earth's surface.
fghsgh
To be really technical in that situation, (to the point of being a dick) wouldn’t the jet of air coming through the portal into the vacuum outweigh that of the earths gravity?
(A bit like the end of portal 2, the jet of air was greater than that of earth’s gravity and moon’s gravity combined. Enough to launch Wheatley & Space core into space)
fghsgh
Another question would be how the portal would project the gravity of the earth?
@@coolguysbro101 The air may push you through the portal, but you'd still feel the gravity as only your skin gets pushed up but everything gets pulled down. So you can still feel the gravity, but you may be vacuumed through. If, however, you keep the portal open for long enough and the pressure evens out, gravity will have its influence back.
@@fghsgh Following the premise that portals do exist, they could not allow to gravity to pass through them because if they did their own existence would not be possible, since the implications of the bent of space time caused by gravity would affect the meter around the other portal leading to a massive tidal affects in the earth what would most likely tear apart the planet.
I think A. Because if you put the two portals in exactly the same place and pretend that they are moving by themselves towards you that'd be exactly like being stationary as if you went through it then you wouldn't suddenly go at a higher speed than you were standing as you enter the portal and exit it from the same place and since that place is your position then you're stationary. I am just assuming that the portals are just taking you from A to B and also that they don't have a thickness. Correct me if I am wrong.
I believe option A makes the most sense as the cube has no force applied to it when it enters, which means it has no force on the exit, creating no velocity. It wouldn't pile on itself either as moving the orange portal closer past the cube would in turn change the position of where the rest of the cube is at the ends of the blue portal.
Okay but imagine the portal is coming down on you, how fast is it? You would have to exit out the other side bit by bit the same times each part enters. If it happens slowly, you can see on the exit portal how a person is being pushed out from head to toe. Now lets say the poral moves faster, their toes come out almost immediately after their head, their body would have had to move out that second portal at the same speed of the first portal coming down at them, surely they'd keep the momentum and wouldn't just flop to the ground after flying out the portal?
@@nicholasnolan2086 but they don't HAVE any momentum to keep.
you aren't being pushed through the portal, the portal is being pushed through you,
remember, a portal is just a hole with disconnected ends.
*_"It wouldn't pile on itself either as moving the orange portal closer past the cube would in turn change the position of where the rest of the cube is at the ends of the blue portal"_*
That's movement. You've just described movement. Look up the definition of speed and velocity, they are both defined by the rate at which an object changes position in space (one being directional).
At a fundamental level you're trying to argue something moves without obeying the laws of motion. Which state that the object will continue its current state of motion when there is nothing to change it.
@@midas.mp4 *_"but they don't HAVE any momentum to keep. "_*
The fact the portal left a stationary exit, something that requires velocity and momentum proves that they do. Portals alter momentum of objects passing though them. It's something they do even with the basic portal fling as both momentum and velocity are defined as having a direction and portal flings are all about changing the direction an object is traveling. And furthermore that's shown to be a change of movement that does obey the laws of motion, which continues when there is nothing to change it.
In other words, you're trying to argue the portals induce a change in movement that don't obey the laws of motion when they already show that they induce a change in movement that does.
except because of relativity, a cube moving through a portal is the same thing as a portal moving through a cube.
Shoots out the portal at an angle, again it's relative speed so it's equivalent to it travelling at a angle towards the portal
damn i want this as a real level to play, pretty sure it won't work with the engine or something tho
Or equally, goes straight up if we're considering portals to work using option A
not really, because the other end of the portal is not moving also the portal has to interact with the object in some way and also had to deaccelarate due to the conversion of energy and impulse. Also your relative speed argument works against you, because if the cube shoots out at an angle you are changing the relative speed. Before it was moving downwards and "sideways" relative to the orange portal and afterwards it would move "sideways" and up relative to the blue portal. You can not just change the frame of reference, when looking at relative speed once you picked one you have to work with it.
@@jantemili I really think it could be made to work.
But what if it is As hypothesis... It would go straight up but the cube would be morphed as each "slice" of cube will be more off set as the entering portal moves. ... I still like B more but just thinking of A is still interesting
Fun fact: the portal gun is also called the handheld quantum tunneling device
In the old test areas sure
@@beachchaos1863 still cannon
@@beachchaos1863 in portal 1 im almost sure that glados calls the portal gun like that when you first find it
@@Just-An-Average-Guy Even in Portal 2 there are posters on the wall with quantum tunneling device written on it
let's face it, if you want something to sound sci-fi, just add "quantum" to it.
Like my quantum toaster, and quantum pogo stick.
Quantum jellybeans. Perfect name for a sci-fi noodle shop would be "The Quantum Wanton."
Quntum stippling. Quantum localization unit. Quantum powder. Quantum axle.
You get the idea.
Seeing as a portal is either making a hole in the wall that leads to somewhere else (worm hole) or is something that isn't really there, like the wall is still there but when you apply pressure to it it let's you teleport.
We can basically rule out the option of it flinging out, the real question is does it plop out or does it crush. And I think the answer is It pops out either way, because if it was about to crush it would defy newton's law saying for every force there is an apposing force, so it would apply a force and would go through
Portals in the games show that they don't merely teleport or lead something somewhere else. They outright change the motion of whatever passes through them when judging things within the same co-ordinate system: ua-cam.com/video/ASUUN0W4_JY/v-deo.html
Following the idea that the object exiting velocity relative to the exit is the same as its entering velocity relative to the entrance (basically necessary for the structure of the object's matter to remain consistent) means that the portal would change the motion of the object in such a manner that it would result in B.
Incidentally arguing that it would apply a force and go through while following newton's laws would mean B also happens. You've argued a force gets the cube through the portal meaning it has gained motion, newton's first law says it would keep moving in said motion as there was nothing to stop it from moving at this speed afterwards.
The cube isn't going into the portal at speed, the portal is going around the cube at speed, so I'd think that the cube would just plop down as if you'd dropped it on the other side of the portal
@@MikeMichelson-vv4zb it'd be like if I had a cup and slammed it down around a wooden block. The block doesn't jump up and hit the bottom of the cup, it stays still, if the entrance to the cup, is just a portal this time, I'd expect the same result. It's fun to speculate either way and I DO realise that this video is just for fun speculation
Too many people use the word "paradox" when what they're talking about is a "conundrum" …
Thank you for this comment. I finally decided to watch this video because I had never heard of the “portal paradox”. Then I was like, where is the paradox?
They don't even solve the conundrum , just giving wrong answers.
Paradox gets more clicks tbf
@@scalpingsnake That would be a sad commentary on a channel that purports to set people's thinking straight about complex topics....
@@martinconrad9260 I prefer to blame UA-cam. UA-cam make it necessary for clickbait in order to get the views you 'deserve'. Of course there are also the videos that don't deserve them and clickbait purely to trick people into watching and maximise views I am referring to the fact that respectable channels also do this because otherwise they simply won't get the views they probably should get.
In the game, GLaDOS explicitly points out "how the momentum is changed [when going through the portal], or more precisely how it is not" in a situation where portals are perpendicular to each other.
I find that difficult to interpret in any way other than "B", that is, momentum is maintained, but frame of reference is shifted (and rotated) from one portal to the other
true , all these terms are relative and we can only determine in one frame possible , thats how our physical world works and portals are (as of now LOL) not possible . It doesn't satisfy space-time laws we have .
If you take a piece of cardboard and put a hole through it and drop it onto a ball, the ball doesn't go flying out the other end. I think portals are like a hole in that cardboard, but the cardboard has no width and the ends can be anywhere. That would make A be the correct answer.
@@noskillpureandy Yeah, but relative to the cardboard hole, the ball *is* flying out the other end, so option A would no longer work.
@@Guinea.Pig-Gaming so if for some unexplainable reason, if a hula hoop drops around me at lets say 20 mph and I jump through it while its still falling, then I should gain enough energy to jump much higher and much faster then normal.
LazyKirby57 Not relative to you, but relative to the hula hoop.
Nice video man!
I would assume that it would plop out, and not fly out, because imagine the portal as a ring/hoola hoop, it just has a distance between the entrance and exit, a box that has a hoola hoop slammed down around it DOES NOT send the box flying up, it stays there, without momentum, therefor, in should be the same scenario if there were portals to do it with.
But here is the problem with your example. If the cube does only retains its moment and none of the portals then it shouldn't be able to go through the portal in the first place. In order for it to go through the portal at all it needs some momentum for the first particles to move out of the way otherwise they would just be teleported into each other. And for your example with the hoola hoop both sides are moving at the same speed, while portal one would be stationary. The two possibilities would be it would have momentum relative to the entry portal and would be sent flying or it has momentum relative to the exit portal in which case you would have two stationary objects coming in contact which is impossible so the portal acts like a wall.