/sci/ - Science & Math

>>3277440
Here's another one for you, OP.

You create a total vacuum in a room. You create one portal on the ceiling and another on the floor directly below the first portal. You then drop a rock into the portal so that it falls forever, but with no terminal velocity to slow it down, does the rock accelerate forever?

lol, this was on reddit earlier.

erm, on 1, it will fall continously.
on 2, the rod is compressed against itself and will either bend or snap.
on 3, considering that it is falling in #1, it will shoot out of the new portal and fly across the room at terminal velocity.

>>3277465

Doesn't the portal being open ruin the vacuum?

My brain hurts. The neurons in it were not designed to think in five physical dimensions.

A: I'd guess it falls until it hits terminal velocity, assuming it was only being held up before by your hand and some some property of the Portal.

B: Keeps falling, shifts part of the mass into whatever dimension allows portals to work.

C: Snaps like the fuck.

>>3277469
also, that third one was done was done at the end of the portal 2 zero punctuation episode.
2 portals were on the floor and ceiling, with a cake falling between them and accellerating up to escape velocity. he shot a portal at the wall and the cake flew out and smashed an imp through a wall.
i chuckled.

>>3277477
no, the both portal exists lead to the same vaccuumed room.

>>3277478
why would it snap on #C?
i think you've read it wrong.

>>3277440
1) It depends which way gravity is
2) The rod breaks
3) The rod breaks

\thread

>>3277490

Because the opposing ends of the pole are stuck together, which can only happen if the two portals it is moving through are parallel. If they are not, either the solder connecting the two ends or whatever is the weakest part of the pole breaks as it is not able to connect those two points in normal space.

As the other option is "Infinite mass is created from nothing" I thick Occam's Razor favours my answer.

>>3277465
Let me continue:

Let's use the same aforementioned vacuum room and portal setup. Now drop a magnet into the portal and set up a coil of copper wire around the portals from floor to ceiling. You have now created a hypothetical perpetual energy generator.

>>3277440
The rod is never infinite of length, it's length is the length of the portals. When you move the orange portal, you break the rod back into its original length.

Portals violate almost if not all rules of the universe.

No one is wrong and no one is right because it cannot happen and you cannot discuss it because it contradicts with itself at every turn.

>>3277510
i think that in the instant you fire the portal at the wall it would cut the rod, in the place exactly where it is entering one portal and coming out of another,
then the rod shoots out.

>>3277490
The portal's connect to points in space discreetly. They do not "warp" space, or cause the objects in space to be warped.

If a senario is devised in which an object should become "warped', THE OBJECT WILL JUST BREAK.

Portal is very very very very very basic physics.

>>3277521

>>3277514
even with the rod linked together, i think it would still follow the same rules as a guy being crushed between portals, so it will bend or snap. its length stays the same.

>>3277521

Of course it's impossible, it's a thought experiment, lighten up.

>>3277542
It's not much of a thought experiment when you can hardly be wrong.

>>3277545

You can still argue, and the argument with the most logical reasoning for and least arguments against would be the "right" one.

>>3277545
Some explanations are more valid than others. you can still imagine how the physics would work if you have played the game. gravity is always downwards, momentum is conserved.

saying "i think the rod tunrs into a duck" is not as valid as saying 'the rod will fall into one portal and out the other'. just because you cant be proved wrong doesnt mean that every answer is equally valid in this thought experiment.

A. It would seem weightless, if you pushed it down it'd continue at the same speed.

B. The rod would be compressed. Depending on if portals can be affected by the thing passing through them the portal may be held up, or the rod smushed.

C. Portals must close for a brief moment before opening in another location, Rod would be severed.

>>3277551
A.
keep in mind that garvity stil exists. all the aprticles are in the space between the portals, they only teleport when they go through one of the portals. all the particles on teh rod are attracted by the gravity of the earth, so are pulled downwards and will accellerate down-wards. this make the part of the rod close to the blue portal fall into it and reappear at the orange portal, where it is STIL attracted by gravity in the same direction and will continue to fall. It will only stay still if forces are equal, and they are not. portals provide no force on their own, and the force of gravity still exists.

Here's what you dumb dicks should do
1) Get the source code to one of these portal games
2) Simulate all these asinine scenarios
3) See what happens
4) ???
5) Fuck off

The first questioned seemed fairly obvious, the pole would fall downwards until it reached terminal velocity similar to what happens when Chell falls through floor-to-ceiling portals. Not sure what would happen if you tilted the rod though.

Question 2 and 3, however are complete mindfucks.

>>3277512

Let's still use the vacuum room setup:

Drop a rock into the first portal and have it accelerate until desired speed is acquired (1000km/h, 10000km/h, 100000km/h, faster than the speed of light?). Then open a portal outside the room.

You now have a "portal gun" that can fire projectiles at ridiculous speeds.

And to answer OP's questions:

A: The rod falls infinitely
B: The rod is snapped or crushed.
C: The rod is severed and shoots across the room.

>>3277551
B. the portal cant be held up. no force can interact with a portal as it is just empty space. you can only interact with the wall, floor or ceiling that the portal is on.

I agree with you on C.

>>3277577
joyless asshole killjoy detected.
enjoy going full life never being emotionally fulfilled.

Any ideas what "Part of your comment isn't allowed to be posted :(" refers to? Tried to post my own explanation and got this unexplained shit.

Oh wait, guys I just remembered.

In B, remember in game that anytime a portal is on a moving object it gets instantly disconnected. So you can't move the substrate the portal is adhered to without destroying the portal.

>>3277551
>>3277584
I don't think the rod would be weightless, nothing is holding it up. It would keep falling through the portals in the same way a stream of marbles would.

>>3277601
This. It seems the last scenario would snap and launch the stick, while in the first it just keeps falling.

However:

Situation D:
What happens if you take the falling stick in the first situation and tilt it?

>>3277601
couldnt on portal 1, but you can on portal 2. they changed the rules =p

>>3277601
This. Didn't you guys play the games?

>>3277616

You get a Kinetic Kill Vehicle.

>>3277622

No, there are things that move or link through Portals, but i still can't remember a portal ever surviving a moving platform.

1: It'd accelerate downwards, and would get closer to the speed of light as it continued.
2. the top portal panel would fall to the side while remaining horizontal
3. the pole would be cut off where the old portal finished.

>>3277616
the rod bends or snaps.

>>3277601
>>3277601
> anytime a portal is on a moving object it gets instantly disconnected. So you can't move the substrate the portal is adhered to without destroying the portal.

This couldn't be a rule for portals since motion is relative. This would leave portals as the only thing capable of sensing "true" motion throughout the universe, which is the same as single out one random velocity.

Basically, if this were true the motion of the Earth would prevent any portals from being created in the games at all.

Thus, we conclude portals can indeed be crated on moving surfaces, which leaves us with our mindfuck.

>>3277634
on portal 2 they can.
http://www.youtube.com/watch?v=S1AIR6m8uLk

Portals clearly can persist on moving surfaces since the earth is moving. Problem?

>>3277650

Portals seem to run on Newtonian mechanics.

>>3277655

Right. the Laser thing. Completely forgot. Consider my theory rescinded.

>>3277588
Holy shit. You get your "emotional fulfillment" from thought experiments derived from fantasy-based video games? That might be the saddest thing I've ever heard.

>>3277663
Yeah but:
>>3277659

>>3277665
Then you havn't been on 4chan long enough.

>>3277665
no. its just obvious that you have no sense of wonder or curiosity about these kinds of things. thats pretty sad.
sad miserable boring person...

>>3277663
>>3277659
I propose a law regarding portal motion. Once two portals have been created, they must maintain the same locations relative to one another, yet can move in tandem. Therefore, both portals can be created on the earth or inside a train carriage, yet one cannot be created on the station and the other the train.

>>3277677
So what would happen if I created one portal on a fixed wall and another on the side of a train and attempted to drive the train?

>>3277665
It's that fantasy based line of thought that all art forms were created and from where all science was born. Thanks for negating all of humans most powerful creations. Video games are the constellations of 2000 years ago

>>3277675
Amazing, I actually feel genuinely sorry for you, and I initially just thought you were another /v/ obsessed loser... but it's worse than that.

If you find "joy" and "emotional fulfillment" from this completely useless bullshit, then your life must be awful. You know, actual SCIENCE is pretty fucking interesting if you can step away from your level 60 goblin warlock night elf mage for just a second and maybe open a book.

And shit, I mean, I play video games too, and I enjoy them now and then... but if this is the state your life is in, the train has gone completely off the tracks long ago.

>>3277683
lol, drive the train through the first portal!
oh my god, just imagine.
the train would come out the side of the train!
my mind is so full of fuck.

>>3277684
I didn't think this thread could get any more depressing... Well, I'll leave you guys to it. Have fun with all the emotional fulfillment going on in here.

>>3277689

Not the guy you are arguing with but...

5.4/10 : you made him respond.

Fuck it, I'm going to get to work on an infographic for paradoxical portal situations.

How about placing a portal on ice, and melting the ice? With a stick halfway through the portals?

>>3277689
first of all, the whole point of computer games is to have fun, or 'joy'.
secondly, i said YOU will never be emotionally fullfilled because YOU are a joyless waster. i never said computer games make one emotionally fullfilled.
thirdly, i dont play WOW
4thly, yes science is interesting, that is why we are talking about the SCIENCE and PHYSICS in a particularly interesting computer game.

>>3277683
The train wouldn't move. Once placed, one portal can only move if the other moves in the same way.

>>3277696
sure thing autistic fag, go play in your linear world and leave imagination to creative people

>>3277704
portals have no mass, so arnt affected by gravity, so i guess the portal on the ice would stay hovering in mid air while the ice melted away beneath it...

>>3277689

Not the guy you're talking to, but you have said nothing to convince anyone that you're anything other than a joyless fuck who is incapable of even entertaining hypothetical situations. I bet if someone said it would be awesome if people could fly like superman you would say "Bullshit! People cannot fly! You're being retarded!" If you cannot handle a light hypothetical thought experiment, I suggest you leave and take your limited imagination with you.

>>3277691
> train would come out of the side of the train
> this train coming out also has the portal the train is coming out of on the side of it
> mfw

>>3277717
What's on the back of the portal, which used to be touching the ice? Do you see whatever the first portal is placed against?

>>3277720
yeh but i just realised, the whole train wouldnt come out the portal, it would crash into the side of itself.

I have one even worse than:
>>3277720

Place one portal on the ground. Place the other on a free rectangle of metal just big enough for it to fit. Anything which falls into the portal in the floor would emerge from the one on the rectangle.

> drop rectangle into the portal in the floor

>>3277707
were playing by portal 2 rules, hun.
moving portals allowed (just for the sake of thought experiment. its more fun than just "it won't work")

>>3277719
aspies gonna asp.

>>3277724
ooh, i dunno.
i personally think it will look like a blue (or orange) impenetrable barrier. it will look exactly the same as when you place your first portal, and havent placed the second yet. with no exit, it is just a solid fill of colour, and cannot be entered.

Wait, if a train comes of itself trough the side, wouldn't that be the same as a person jumping off a train? hence the train "derailing" right as it exits the portal?

A. Moving the rod in either vertical direction does not change its gravitational potential energy. It's like a ball on a level surface. It's velocity will be constant, assuming no friction. If there are dissipative forces, it eventually comes to a stand-still wrt the portals.

B. Portals can't be placed on a moving surface (breaks physics, but it's not my rule).

C. Initially, it's in the same configuration as in scenario A. This time, it can gain kinetic energy by falling. The magnitude of its momentum is conserved but the direction changes as it comes out the other portal (same as in the game). Atoms that were intersected by the plane of the orange portal undergo fission.

>>3277734
what the fuck

Tried to make a diagram of a really good one and got "Error: Cannot find record.". I fucking hate this place sometimes, any ideas what this actually means?

<--this.

>>3277795
goes into a different dimension or something... i dunno.
portals going through portals causes some fucked up shit. see >>3277541

>>3277805
Holy shit. It's worse than dividing by zero up in this bitch.

>>3277795
The answer to this is spectacularly uninteresting. Think about it for a minute and you'll see that nothing really happens.

>>3277795

The blue portal would cancel itself as soon as the bottom of it goes inside the orange portal. It only makes sense because a portal can't exist inside of a portal

>>3277822
I honestly can't picture it.

>>3277824
We have no reason to assume a portal can go through a portal.

If it did, the metal rectangle is going to be emerging from the center of itself as it passes through the floor. What happens as the process continues?

>>3277842
*cannot

>>3277795
this gave me a headache

a guy tried it. portal inside a portal video: http://www.youtube.com/watch?v=Rt4VJy8jCIU

>>3277859
connection problems...

>>3277859
what the fuck! why does if flip him upside down when he presses the button to activate it??

>>3277862
well it goes in halfway, then stops and doesnt move any further.

>>3277859
Not that interesting. No idea why the thing the portal is on randomly gets cut in half, doesn't seem to logically make sense.

I know this probably doesn't help much. Someone made an animated gif of this at some point and it makes much more sense.

>>3277888
oh i get it, it jams against the side after its halfway out. portal edges are immovable and impenetrable, so its it jammed and cant fall any further than halfway...intredasting.

>>3277888
Finally wrapped my head around it, thanks.

Moving portals have some seriously weird consequences.

>>3277795

>>3277939
What if you place the upper portal in at an angle, so the emerging block never catches the inside of the ground portal? Where is your fucking god now?

>>3277939
lol@filename, makes more sense now.

I thought that portals closed when moved.

It's a good thing that portals break the principle of relativity, if SR was still valid it would mean they violate causality.

>>3277968
... assuming they work instantaneously.

>>3277970
How could they not? If one was placed three light years away and you threw a pencil through, would it just hover at the border or what?

>>3277976
no, portal would crash.

>>3277976
the universe would be logically forced to create some kind of deity to prevent this at the last moment. so don't fucking try it.

>>3277976
They don't conserve momentum, I see no reason why they couldn't break conservation of energy temporarily.

>>3278007
They certainly do conserve momentum, played the games? Perhaps the energy would just be forced out as a blast of heat and sound or something.

>>3278014
Momentum is a vector, not a scalar. Magnitude is conserved, not direction.

You morons.

Portals obey the laws of thermodynamics, and that means it can't keep falling forever forever, producing
> HURR DURR perpetuum mobile.

Think about it this way. Take our 3 dimensions, bend them, and you get 4 dimensions.
if you were to put portals like that, portals being two sides of a wormhole with a distance between them of almost zero, then in that very small ACTUAL space between the portals, the mass would be be equally far away from the source of gravity (aka FLOOR) and would be stuck there, because the attraction would cancel out.

>>3278032
>direction not conserved
Nope. Have you not played portal 2?
>>3278085
Nope. Have you not played portal?

I haven't played portal 2. Correction: direction is not conserved in Portal.

>>3278110
firin' it up now to see if it is.

>>3278093
I have played portal, but if we want this to be even slightly possibly real, then we can't use the physics in portal because they're all fucked up.

>Light bridges
Light has mass and can cause pressure, but c'mon?

>Violating TD
Nobody does that shit.

>....

>>3278119
> falling eight stories
> saved by springy boots

>>3278126
Yeah that too. Including acceleration gel, god only knows where the fuck it's getting the extra energy from.

>>3278119
Pretty sure nobody here insinuated portal was possible in reality.
>>3278110
'tis conserved.

>>3278138
Absolutely not. You can have a system with a single object moving in one direction, place two portals on the same wall. Without any interaction with the outside world, you can reverse the object's momentum.

>>3278190
Ahah, you're assuming that the rotation isn't allowed to change the momentum, I'm not. Their direction and energy when entering the portal relative to it are identical to their direction and energy when exiting the other, relative to it, regardless of the orientation of the exit portal relative to the entry portal.

>>3278190
> nope.avi

The object itself travels through a straight line, only space itself is "bent" through the portals.

>>3278224
>nope.exe

There are no straight lines in curved space. If we're going to explain the portal phenomenon in terms of curvature of space, the question "is the object's momentum the same before and after going into the portal?" is nonsensical. In curved space, equivalence of vectors can only be defined locally.