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A or B?
A. 67%  67%  [ 18 ]
B. 33%  33%  [ 9 ]
Total votes : 27

Jono
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23 Feb 2012, 2:42 pm

Shorttail wrote:
Jono wrote:
Imagine you are sitting in the first room, watching the doorway to the second room moving towards the stationary (that means not moving) box next to you. In this situation, the second room is moving towards a stationary cube and not the other way round.

Doesn't that completely disregard the nature of relativity?


No it doesn't, it is just a description from the point of view of a different reference frame. All I'm saying is that from the perspective of the first room, the second room is moving towards the box, whereas from the perspective second room, the cube is the thing that's moving. In fact that's why it's called relativity, because descriptions of nature are relative to different inertial frames of reference. In inertial frames though, the conclusions should at least end up being logically consistent. The paradox found is due to the reference frame not being inertial.

Note also that I'm talking about Galilean relativity (the type of relativity already known to Newton), not Einstein's relativity.



Reynaert
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23 Feb 2012, 3:59 pm

Jono wrote:
As for your diagram with the barber pole, that appears correct as velocities V1 and V2 remain constant. However, as soon as the one portal, and hence the barber pole, stops moving, I think there will be an inertial force acting on the rat to keep it from flying forward. I guess it can be hard to get your head around the the fact that the two frames are essentially the same room, it's just that the portals connect different places in 3 dimensional space to each other.


That's not how frames of reference work. I know it can be hard to get your head around the fact that there are different frames of reference, even inside a single room.

If the two portals are moving in reference to one another, then the only plausible explanation is that any object entering one portal will jump to another frame of reference. If the portal accelerates, then it gets even more hairy (it exerts forces on any objects halfway through). But still, B is the only logical solution, as evidenced by the barber pole thought-experiment. (Suppose, for a moment, the portal doesn't stop moving when the pole is through. Suppose it was floating in midair, and the portal just keeps on going. Then why should it suddenly stop when it's all the way through?



Reynaert
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23 Feb 2012, 4:04 pm

The_Final_Boss wrote:
Here is a video showing exactly what happens in-game


The platform was moving much too slowly to actually eject the box, so it's not really a good test. Although it's obvious the engine flips out bigtime.



Hero
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23 Feb 2012, 6:45 pm

Actually, I'm pretty sure everyone is wrong.
I just did some numerical thinking in my head. I was thinking about what happened at a subatomic level. Estimating the force and pressure.

A Is still a possible answer, but it depends on both the speed of the dropping wall and the material on the otherside of the portal(aka where you come out).

What actually happens is answer C...you get smooshed to death. However, that is only assuming the force acting downward on you is greater than your body can handle. So the answer is either A or C, and what happens at subatomic level is C.

There is however a way to actually propel something. However, that requires that something is actually above the portal exit and a protruding item is sitting below.

If you are above the exit, than as the lift moves downward, air would move into the new space. This would cause pressure. If your below the lift, you would see the air get squeezed in the new room. I bet you could create a heater or cloud machine out of pure portals, thinking about it in more depth now.

You will not get propelled if you were below it. The force of the two differing sides is a result of pressure. The new material is forcing the old material out of the way(but its not actual kinetic force...the new material isn't actually moving), causing it to react with equal downward force. It is a little wierd to think about but you aren't actually propelling yourself. Rather the portal is causing an aftereffect where new material can result in pressure without actual movement. So the paradox here has less to do with the frames of reference and more to do with a free energy loophole. (supposedly its possible for wormholes not to violate causality though. In theory, they are supposedly possible. As a result there must be a way to do it without the loophole.)

In short, if you are below the lift, you will have to calculate the existing pressure of the two sides, density of material on other side and speed of the portal to determine how much you get smooshed (something from the pressure of a breeze to instant death), or to see how far your would get propelled if you were above the portal.

The portal line determines the direction of the force in this case. In otherwords, the equal and opposite reaction is happening at the center axis of the portal. If your above it before it moves you go up, and if your below it before it moves you get smooshed.

Now the question arises, what happens once you are halfway through. Well, all things considered, you should reach equilibrium....meaning nothing. You might actually reach a state of weightlessness with the feeling like your whole body just pushed together a little bit like a human slinky. In fact, this is probably all the more reason you shouldn't enter a moving portal. A portal moving at 60 miles an hour would probably kill you once you were near the equilibrium. Than again given the force would dampen across your entire body and the surrounding material, and it might only break your back and crush your lower intestines. So, you'd make it...but in one hell of a lot of pain, in that case.

However, looking at it closely...I think its buoyancy. I think, you are creating some wierd 4th dimensional cosmic buoyancy problem.

So, in conclusion.

A is possible.

B is possible for objects that exist above the portal. At fast enough speeds you will be able to propel with a strong wind tunnel effect.

C is possible as well...and likely the most constant outcome of all cases unless your moving at very very slow speeds.

--------------------

Added development...As your going through the portal at equilibrium, half your body is getting propelled, but your lower body is getting smooshed. So your ripping your apart at the nuclear level, at the same time as imploding....

As a result, answer A might be the cause...I'm not going to do anything more than the estimation for a forum question. Is there anyone willing to plug the numbers in to see what happens when a body is ripped apart and imploded simultaneously?

My guess is nothing and therefore answer A.

So Its either A, or A,B,and C.



Jono
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24 Feb 2012, 12:45 am

Reynaert wrote:
Suppose it was floating in midair, and the portal just keeps on going. Then why should it suddenly stop when it's all the way through?


Hang on. Maybe you're right. I didn't think about what would happen if the barber pole is the whole way through before the portal stops moving. Maybe I made wrong choice for what to consider as the accelerating frame. :?



Last edited by Jono on 24 Feb 2012, 3:01 am, edited 1 time in total.

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24 Feb 2012, 11:39 pm

Jono wrote:
I also thought about it that way but there is a reason why I emphasized that the frames must be inertial. Here's my full explanation:

Let's consider the portal as simply a doorway between 2 identical rooms just like you have above. Now, let's go over your analysis again. You are sitting in the second room, looking through the doorway at the box in the original room. That first room, and hence the box as well, is moving towards you. Now, in accordance with Newton's first law of motion, the box has to continue moving at the same speed, and hence fly into the air, when that room suddenly stops moving. This is precisely the prediction that you came up with in your analysis above, so far so good. However, now let's consider the analogous situation from the point of view of the other room. Imagine you are sitting in the first room, watching the doorway to the second room moving towards the stationary (that means not moving) box next to you. In this situation, the second room is moving towards a stationary cube and not the other way round. Since the cube is stationary, it has to remain stationary (again by Newton's first law) even when the second room stops moving, unless of course, a force acts on it, causing it to fly into the air. Now we seem to have a paradox as it appears as though both A and B in the first diagram could be true, depending on from which "room" you are observing the box.

The solution to the above conundrum basically comes down to this:

As long as two frames of reference are moving at constant speeds relative to each other, with the frames being the two identical "rooms" in the description above, the description of the physics in both frames can be considered identical would still be consistent. However, in order for one of the rooms to stop moving with respect to the other one, it has to decelerate until it's speed reaches zero. During this time of deceleration, even if it were just an instant, room is essentially slowing down and therefore no longer moving at constant speed, hence the frame is no longer inertial and descriptions using identical physics are no longer valid. Usually, when comparing non-inertial reference frames, one would have to make a choice of a preferred frame and then introduce inertial forces (also called fictitious forces) in the other one in order to resolve paradoxes like the one above.

For example, let's say you were in a passenger seat of car that's moving along at a constant speed. Now the driver slams on the breaks. Relative to the road, you have to continue moving at constant speed in accordance to Newtons first law of motion. However, relative to the reference frame of the car, one has to introduce a fictitious force that flings you forward, meaning of course that we've chosen the road as our preferred reference frame. Now the choice of a preferred frame is not arbitrary and in the case of this car example, we've chosen the road as our preferred frame because when the driver slams on the breaks, a force is applied to the car, not the road and the rest of the outside world, in order to decelerate it. This, by the way, is also why one needs to add a centrifugal force in a rotating frame.

Now getting back to our original problem. I would associate force responsible for decelerating one of the "rooms" to a force acting on the moving pillar with the orange portal on it. Therefore, to me "room" 2 appears to be the logical choice as the accelerating frame since it's the room "behind" the orange portal, thus making the original room, where the box is stationary, my preferred frame. Well, if that's my preferred frame, then the laws of physics should hold in that frame without including any extra forces. On the other hand, there must be some kind of inertial force that would stop the box from flying in the other frame. Thus I arrive at A as my final answer. 8)

As for your diagram with the barber pole, that appears correct as velocities V1 and V2 remain constant. However, as soon as the one portal, and hence the barber pole, stops moving, I think there will be an inertial force acting on the rat to keep it from flying forward. I guess it can be hard to get your head around the the fact that the two frames are essentially the same room, it's just that the portals connect different places in 3 dimensional space to each other.


Ok, I think I follow that. So, when "room 2" stops the box inside it will go from moving w.r.t. that room to being stationary w/no forces acting on it, so room 2 isn't an inertial frame. But what if the portal never stops moving? -- Ok, I guess given the setup (diagram #1) where the portal is moving towards the floor it has to stop. What if there was an infinitely deep hole that it descended into?

Ok, this is starting to give me a headache, now. :lol:



darkfuji
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28 Feb 2012, 7:04 am

the cube has no momentum going in so no momentum going out. A.



nat4200
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28 Feb 2012, 7:39 am

Redacted



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Apple_in_my_Eye
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28 Feb 2012, 6:03 pm

nat4200 wrote:
For those arguing that B would happen, not in a computer game engine, but in real life with a wormhole/Einstein-Rosen bridge, because of reference frames; I suggest you try to replicate the setup thusly - drop a hula hoop as a stand-in in for the portal mouth over a box such that it falls around it without making contact, observe the motion of the box.

If the hula hoop has a room attached to it and you're strapped to a chain in that room, then you will see the box moving. A portal is not a hula hoop with nothing attached. Bad analogy.



nat4200
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28 Feb 2012, 8:50 pm

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nat4200
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28 Feb 2012, 10:34 pm

Redacted



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Hero
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29 Feb 2012, 2:09 pm

nat4200 wrote:
Apple_in_my_Eye wrote:
nat4200 wrote:
For those arguing that B would happen, not in a computer game engine, but in real life with a wormhole/Einstein-Rosen bridge, because of reference frames; I suggest you try to replicate the setup thusly - drop a hula hoop as a stand-in in for the portal mouth over a box such that it falls around it without making contact, observe the motion of the box.

If the hula hoop has a room attached to it and you're strapped to a chain in that room, then you will see the box moving. A portal is not a hula hoop with nothing attached. Bad analogy.


If the portal is extremely warped space-time (I really can think of no other options), then I don't think you can consider it "attached" to the rooms or objects either (and incidentally I don't think its "mouth" would cease to "move" when the surface it is co-located with contacts the platform)

Here's a diagram I made (in MSPaint) showing the box staying resting on a floor despite being warped (I think it should start to slide or pivot around it's bottom-right corner due to gravity at some point but left this out for simplicity sake). I assert that it is roughly equivalent to the original diagram, the main changes are:
1. the removal of the surface the "portal opening" moved with
2. the "portal exit" has been repositioned for a more convenient depiction of the wormhole itself (shown in grey in the diagram)
3. the "portal opening" is shown to continue "moving" below the floor surface (the face of which is depicted as the horizontal blue line in the diagram)
Image

If there were some way to stop the "portal mouth's motion" at t=1 without invalidating the setup (I doubt this would be possible IRL), but let's pretend for a moment god, gods and/or a wizard are involved, note that the box's reference frame still includes it sitting on the floor surface, stationery relative to this surface, and apart from the shift in the gravity it experiences - I don't see how the reference frame assertions account for the box suddenly "flying" away from this surface.

That is, the box's perspective, and inertial reference frame, if it can be said to have one (and with the changes in the warping of it's local space-time, I'm not certain if it really can), it would have to remain at rest relative to both sides of the worm hole simultaneously. I'm not sure that the distance to a wall or ceiling, which it "sees" changing through the portal, is equivalent to that surface approaching with at a constant velocity.


The complication is that portal is a game, and in the game the wormhole has no space inside. It is warping space-time, but not in a context that you shrink or alter objects that go through. Its essentially nothing more than a rip. Basically its folding a piece of paper and pinching. The pinch is the hole.

However, you are bringing up the point that makes basic sense. The problem is, both scenarios are wrong.

What occurs between the sides is entirely determined by the makeup of the different sides, and the speed of the moving portal(it gets even more complicated if both fissures are moving.)
I brought up earlier in the thread some thoughts on A,B, C possible choices. Some of it confusing because I was fleshing out the concept at the time so it was really an amalgamation of ideas. However it is also most accurate.

It has everything to do with this:

Quote:
...Also, if "A" were correct, then the first infinitesimal slice of the pole, upon emerging from the lower portal, would have zero velocity. The rest of the pole would then "pile up" behind the that first slice, preventing the pole from proceeding further...


The entry portal is moving, each slice will push the next slice up(if your looking at the portal in front of it, nothing is actually being cut, it is descriptive). The pole would only be prevented from proceeding further at the speed of light. This is because the energy would accelerate the energy ahead beyond nominal capacity. So either entropy would have to further alter the portal setup in that instance, or the energy simply could not pass through. Your definition of "Warped" could be considered that entropic event.

However, if an object only moves up a millimeter beyond the exit...is that really call to reason to consider it a scenario of B? I would argue no, as I think others such as yourself, Nat, would also argue. It is in fact A by any measure of description in that case. Something so small should never be considered cause for B.

As I mentioned before, it is possible to create a valid B scenario and the same with C.

This is because as you adequately described, the object itself is not moving, but is shifted by spacetime. This is irrelevant on the whole though, because the spatial artifacts can produce crushing, displacing, and pulling motions regardless. It just isn't truly kinetic motion.

-----------------------------------

Let us utilize the instance above of the previous slice to slice translation occuring, assuming these things:

1. You are in a vacuum
2. The object is a perfect solid sphere and unmoving
3. Only the moving entry and stationary exit portals exist beyond the two previous facts


As the first slice moves beyond the portal, absolutely nothing occurs. (To put it more bluntly, the very first atomic structures that pass into the portal will ALWAYS result in a case of A. This is absolute.) Once the second slice crosses into the threshold, the first slice will be pushed up with a force equal to the displacing object behind it. Now I'd like to stop here and note several descriptions of events resulting from this scenario.

- Most obvious and direct is that the faster the portal entry is moving, the greater the outward force will be
- The nuclear force still applies in this portal scenario. As a result, something overlooked by most engaging the question is that not only will everything behind the first slice be pushed back with equal force, but the atoms being pushed ahead will be held together by the forces maintaining structural integrity. I bring this up, because what most likely don't realize is this situation has a slight difference of effect to standard laws of motion. This has everything to do with the lack of true kinetic motion, which is being replaced at the exit,= by the movement of only the portal entry and the standard mass.

If you are only calculating force for the exit, than all standard equations apply.(math would provide a simple answer; My guess is this is what most people are doing) However, if you want the reality of the situation, you need to consider all aspects of the scenario. Namely, that all pieces of the sphere are not experiencing force with the same degree of reference. Since not all atoms are experiencing the "movement" with the same degree of reference, how force is buffered across surfaces, and how the nuclear force holds the object together can become complicated.

If for example, you were to move the portal with enough speed to cause the second slice to push the first slice with enough force to break the nuclear bonds and structural integrity of the sphere, You will actually have a cosmic version of the perfect grinder. You will literally create pure unadulterated radiation from the exit. Basically the equivalent of what a blackhole or quasar does as it propels gasses from their (usually) z axis.

In a normal scenario of kinetic motion...this absolutely would not happen. The object would not normally accelerate to the final velocity instantaneously. Furthermore, you would not create a line in the object that says, everything behind this line decelerate to 0mph instantaneously, while everything else, continue moving with maximal force and velocity. There would be natural give and take in both the aspects of acceleration and deceleration.

The portal alters this scenario by doing just that.

- An additional note is that everything entering the portal will squish just a little bit from reactionary force(though it could easily be insignificant.)

Continuing on

The sphere will push each slice as such likely resulting in a slightly tapered push(Sort of like when a ball hits the ground, but in this case only on the side of the exit, and perhaps marginally at the entry near equilibrium.) This will continue until the sphere has reached relative equilibrium, in which case the force in place + the new force acting upon it will have greater prominence, resulting in the lower half being pulled up by the greater strain on the structural integrity of the object, result in a final small popping appearance(like trying to pull yourself out from being stuck in an enclosure), and squish as the backside makes it through and the sphere develops a stable, equalized velocity across its structure.

Being in a vacuum, the sphere will thus creep away from the exit, as it has no force acting upon it, gradually moving further and further away. However, the final velocity depends on the objects mass and speed of the entry portal. Likely, under most normal circumstances(IE a portal that isn't moving at high speed), the final velocity of the sphere is likely to be extremely low. As a result, the final movement in the vacuum might be B...but A will have happened first, followed by C(or BC). So the stage of an object in a vacuum is actually

A -> BC -> B.

----------------------------------

Now comes the tricky part. What happens with a portal in a vacuum is not what happens with a portal in space with consistent physical properties or inconsistent physical properties. These will all distort the final event, which can result in a final description of A, B or C(or a combination), depending on the scenario.

For example:

- What happens if the entry area has an object filled with a low density gas, and the exit is filled with high density gas or even a liquid like water? I'm not going to go into all of my thoughts here, but to suffice to say, the final product will lean closer to A or C under such a scenario, and less like B.

As you can imagine, the opposite will ring true with High density entry, and low density exit. You will shoot out like a cannon if the portal is moving fast enough.

- What happens if the exit portal "rotates", but does not translate like the entry.
- What happens if the entry portal is moving at the speed of light? (This was already described above. Entropy either must take over, or you will not be able to move beyond the portal and will be crushed. This is perhaps the only case of C being the sole result). (In fact its the only case where you will never cross the axis of equilibrium).

Or for the coolest effect:

Have the one portal move downward at speed accelerating to roughly match a falling object(from the sky). Jump from a ledge down into the stationary portal on the ground.

- What happens? This goes further back to my cosmic buoyancy problem. You would end up bobbing up and down like a buoy on water until you finally hit a relative speed with the portal and amongst gravity, resulting in a final appearance of purely stationary freefall. You would look absolutely magical. :lol:



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29 Feb 2012, 6:17 pm

A is surely the answer.

While the object enters the portal quickly, it has no velocity.