Comment on Which is it Lemmy?
Duamerthrax@lemmy.world 3 days agoIf the portal is being pushed down by the piston, that means it interacts with piston. A portal isn’t a lasso because lasso’s exist and have known rules to them. The only things we can know about portals is what’s presented in the hypothetical.
Bytemeister@lemmy.world 3 days ago
Sure, because the portal is affixed to the piston, but you should note that the portal is not affixed to the box. The box doesn’t interact with the piston, or the portal, in the same way it doesn’t interact with a hoola-hoop that is passed around it.
Duamerthrax@lemmy.world 3 days ago
If the box enters the portal at a certain rate, it has to exit the portal at the same rate. Unless there’s relatively involved, that has to be true and everything else follows.
How is the portal affixed to the piston? Whatever made up system that affixes the portal to the piston would also allow it to interact with the box.
The box has to exit at the same rate it enters and the law of conservation of mass and energy dictates that no new energy is created and it has to come from somewhere. If there is no way for the energy to be transferred from the portal to the box, then simply, portals cannot exist.
Bytemeister@lemmy.world 3 days ago
It’s doesn’t matter really, this is a red herring.
There is the problem with your logic. The box doesnt move, there is a shortcut in space that moves around it.
EXACTLY!! A is the only scenario where energy (or more accurately, momentum) is conserved in this case. If you want to think about why that is, see my previous post where I extrapolated on a case where a lighter object with a portal on it is moved over the box.
Duamerthrax@lemmy.world 3 days ago
This is not a red herring. A portal can be assumed to be massless and might not interact with anything. In theory, it could have infinite sharpness and cut though the piston when force is applied. But that’s not the hypothetical. The hypothetical has the portal fixed to the piston, interacting with mass. If it can interact with the piston, it can interact with
The box moves in relation to the portal opening. The reference frame is the portal opening. If, from start to finish, the box takes 1 second to enter the portal, it has to take one second to exit the portal. Everything works backwards from this. If traveling through the portal quickly would cause the box to be launched, then the energy has to come from somewhere and the piston is the only source.