this post was submitted on 18 Aug 2023
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I think it has to be A. You figure that if it were B, the people on the track would suddenly be traveling at a high velocity, but the train's velocity wouldn't be impacted at all, since there was no impact between the train and the people. Wouldn't this mean that the portal had created energy, which is impossible?
But portals can create energy. Put one above the other face to face and drop an object into the bottom one, it now has infinite potential energy.
... fuck. You're absolutely right. All my theorems - flushed down the drain.
I mentioned this elsewhere but this line of reasoning may have a huge flaw, and that flaw is that energy has to be spent to maintain the portals operation. We do not currently know what the relationship is between the amount of mass that is moved through a portal and how much energy it takes to keep the portal operational.
So when you take into account the total entropy of the system you also have to include the entropy of the earth and the entropy of the power systems that maintain the portals.
As I said earlier, if you were to put a magnet inside of a vacuum tube that was welded to itself through the portal and then wrapped coils around that tube to drain the electromagnetic energy from the falling magnet, the energy that you were extracting from the system would come from either converting the mass of the planet into energy or it would be a total net loss as the amount of energy needed to maintain the portal would be greater than any amount of energy you could extract from the system no matter how fast the magnet inside of it was moving or how perfectly configured your coils were.
After all, as the magnet approaches the speed of light eventually its mass would be come equal to or greater than the mass of the planet, and that would cause the portal to lift the Earth towards itself.
However, coils on electromagnetics exert electromotive braking Force, and when you account for e that Force you can prevent the magnet from reaching luminal speeds, but I still don't think you're going to have an over-unity device.
Think of a portal as a door, if someone brings an open door up to you (idk maybe it's on wheels or something) and you go through it, you don't suddenly fly through the frame.
If the door is moving 1 meter per second, you are relatively moving 1 m/s towards the door even if you are stationary on the ground. You pass and, although you are still stationary to the ground, you are still moving 1 m/s in the same direction relative to the door. The door is the frame of reference, not the ground.
But that would signify there is an impact? And that you are crashing at 1m/s, if you don't enter in contact? If I'm in my house, I am not moving at 130km/h from the highway near my house?
If you are looking at someone through the portal, they will appear to be standing on a parade float. They are standing still on a surface, but that surface is coming at you.
You won't feel any change in momentum as the portal passes around you, but the ground will be suddenly moving under you.
Yes but relative to you the door is moving away and you're stationary. In this example of the portal coming towards you, therefore upon paasing through the other side of the frame, the other portal, is moving away from you.
In this diagram, it's assumed that the person is the frame of reference, therefore I believe A to be the correct outcome.
Another violation is that they conserve speed, not velocity. Put 2 portals 90° apart. Travel into the first perpendicular to the surface. You'll exit the second perpendicular to its surface. That means you accelerated to change direction, which takes energy. Portals don't conserve momentum or energy.
No way, the portal displaces space meaning it just allows gravity to work unimpeded adding more kinetic energy to the object. The potential energy during a "falling cycle" is infinite but infinitely removed when the spacial disruption is broken.
By moving an object laterally into the portal falling loop, you would do no work and increase the potential energy of the object to effectively infinity. You would be creating energy.
I wouldn't consider that the portal, itself, imparting the energy, though. It's just facilitating an environment where an object can fall infinitely. The portal is outputting the same momentum that is inputted to it. The actual increase of energy happens while the object is falling between the portals.
The portal teleports an object to a position in space with high potential energy, while apparently spending no energy of its own. This action creates energy.
In classical physics you would be right, but in modern physics there is no standard frame of reference. It's equally correct to think that the people are still and portal is moving as it is to think that portal is still and people go in it immn fast speed.
Regardless, people and portal have large speed difference going in, so there will be large speed difference going out.
Fuck, you just made me question the whole thing. Cave Johnson must be turning in his grave.
This is how I always look at it. The portals don’t actually move what is behind them, they are just a portal to that place, so there is no momentum to impart
The matter has to move through the portal at the speed of the train, and it won't suddenly lose all momentum when it's done being pushed through. B imo.