It’s also trivial to make a perpetual motion machine with Portal portals. Just have a portal in the floor that teleports you to the ceiling directly above it, then drop a ball into it. It’ll fall forever, accelerating until it hits terminal velocity (at which point all the gravitational potential energy goes to heating the air it falls through).
If you don’t want to just throw out conservation of energy, using a portal to “lift” things would have to take the same amount of energy as lifting it through normal space does.
Yes, you could fix it by making the portal pay for lifting. An alternative fix would be to let gravity go through portals, so the ball feels the Earth’s gravity by the direct route and also through the portal. Which I think makes the column between the two portals zero G, with gravity returning towards normal as you move radially. This solution only deals with the steady-state though, at the moment portals appear or disappear the gravitational potential energy of objects (especially those near the portal) would step abruptly.
It’s also trivial to make a perpetual motion machine with Portal portals. Just have a portal in the floor that teleports you to the ceiling directly above it, then drop a ball into it. It’ll fall forever, accelerating until it hits terminal velocity (at which point all the gravitational potential energy goes to heating the air it falls through).
If you don’t want to just throw out conservation of energy, using a portal to “lift” things would have to take the same amount of energy as lifting it through normal space does.
Yes, you could fix it by making the portal pay for lifting. An alternative fix would be to let gravity go through portals, so the ball feels the Earth’s gravity by the direct route and also through the portal. Which I think makes the column between the two portals zero G, with gravity returning towards normal as you move radially. This solution only deals with the steady-state though, at the moment portals appear or disappear the gravitational potential energy of objects (especially those near the portal) would step abruptly.
Its quite a fun situation to think about.