Comment on Which is it Lemmy?
mirshafie@europe.pub 3 days agoIt’s not about whether portals have mass or not. It’s about the box’s velocity relative to the space on the other side of the portal. In the game, as you move toward a portal, you also move toward the objects on the other side of the portal. Therefore you have velocity relative to those objects, and that’s the momentum that is conserved as you pass through.
Bytemeister@lemmy.world 3 days ago
Well, the box’s velocity relative to the space on the other side of the portal is 0, so that is why it does move.
That’s what this statement means.
mirshafie@europe.pub 3 days ago
This would suggest that portals in the game Portal are flat paintings, but it’s not. As you move around or toward the portal, your distance and angle to the objects on the other side of the portal move in your frame of reference. Therefore you have velocity relative to those objects. Not to the portal itself, not to the universe behind the portal as a point mass, but to the spatially separated objects on the other side of thr portal individually.
Bytemeister@lemmy.world 3 days ago
No, it doesn’t imply that portal are flat paintings at all.
Yes, but only technically so because those distances and angles change outside of the portal. Your path through the portals isn’t real, it’s a shortcut through space. This is why an object that is moved through a portal has momentum, but an object that a portal is moved over does not, the two scenarios are not the same when you have a frame of reference that includes the space on the other side of the portal. They are the same if you ignore that space in your frame of reference, but then any conclusion you come to about things outside that frame of reference are invalid.
mirshafie@europe.pub 3 days ago
Ah, so you’re saying Portals are not flat paintings, they’re flat TV screens which project a representation of the universe behind them like based on where the observer is. Upon impact with an object they then store the objects momentum relative to the TV screen, teleport the object to another point in the universe, and then transfer the momentum to the teleported object. Got it!
One minor inconsistency is that in the Portal universe, objects transition smoothly through portals and can stop halfway through. But that’s okay since we’re just making shit up anyway.
Circular argument. You’re using your preferred conclusion as evidence for your flawed reasoning.
Velocity is a relative property between two objects. There’s no “I’m moving toward the portal, therefore I have momentum” versus “The portal is coming toward me, therefore I have no momentum”.