Portal Physics

Please excuse the poor graphics, this was all made in a few minutes using paint.


Portals and Gravity

Supposing gravity can move through portals, what would happen. If the portal is on the floor gravity would fall into the portal, pushing out of the other portal. If the portal is on the ceiling the gravity would be falling from it, creating a gravity-vacuum on the other portal. If the portal is on the wall the gravity would have minimal or no affect on the gravity on the other side of the portal.



If two portals are on the floor the gravity in one would try to push at the gravity coming from the other portal, supposing that the gravity is the same going in both portals the reaction would cancel each other out, creating an area of zero gravity.



If both portals are on the ceiling then the tug of gravity would try to pull at the other portal. Since they are both on the ceiling the pull of gravity would cancel each other out, supposing that the gravity tug is the same at both portals. Once again there is an area of zero gravity.



if one portal is on the ground and one is on the wall the gravity falling in the floor portal would come out the wall portal. If you were to jump in front of a wall portal then you would be pushed away.


Likewise if one portal is on the ceiling and another is on the wall, then the suction of gravity of the ceiling portal means that if something is moved infront of the wall portal it would be sucked in.


Now suppose we had diagonal portals? The possibilities are endless! Discuss.


Portals and Time

If you know the theory of relativity you can skip this paragraph, if you don't then continue reading. Light goes at 670million mph, always, regardless of perspective. So if you were going forward at 100million mph, you would still see light going at 670million mph. Now if we had two mirrors and had a photon bounce up and down between it it the photon would appear to be goinh 670million mph. If these mirrors were going 300million mph forward and you had a beam of light bounce up and down it would still seem to go 670million mph. If you were going along with the mirrors it would seem it was just bouncing up and down to you, but to someone standing still it would seem to zig zag. result is that the faster something moves compared to you, the slower it seems to go.



Now if we had a badly drawn spaceship going 300million mph relative to a planet, and you had one portal on the planet and another on the spaceship, what would happen? The spaceship would appear to have time going slower from the planets perspective because its moving, but if you look the the portal the spaceship would seem to be have time pass normally since the portal moves along with the spaceship. The question is, which is correct? What would happen if you stuck your hand in the portal?


I'm no scientist, so if I got something wrong with physics then please tell me.

I disagree with your physics. My understanding is that the easiest way to model gravity is as a wave emitted by massive objects and with a strength proportional to the inverse square of the distance from the centre of that mass.

I think it's fairly easy to demonstrate that portals are transparent to gravity waves - i.e. the two do not interact in any way. Consider a blue portal placed on the floor, on a planet like ours, and the orange portal floating somewhere in space.

Hold an object over the blue portal and it will fall down, towards the centre of pass of the planet, even though a portal is between it and that centre of mass - i.e. the gravity waves work exactly the same regardess of whether the portal is present.

Now hold an object outside the orange portal and it will just float there - i.e. no gravity from the planet is propogating through the portal.

Hence, gravity waves ignore portals.

Your second question is actually a paradox as phrased. Relativity postulates that nothing can go faster than the speed of light. But you seem to be suggesting that transition from one portal to another is instantaneous. You can't mix those two concepts together and get reasonable results.

If portals hold with relativity, then matter must pass from one portal to the other portal as a wave which propogates no faster than the speed of light. I think this would solve your question. What you see would be the same as if you placed a camera looking out of the wall where the portal was placed.

Yes, I do agree that gravity doesn't move through portals, since in the game portal there was no evidence of it. This just shows what would happen if gravity did move through portals.

This is srs science. None of your "what if" here.

This convo is way way over my head, i am terrible at physics. But, I think I can say something:

It seems like your conjecture is based on the assumption of portals having no effect other than to just create a hole through space.

However, in the game, they don't really talk about some of the more technical aspects of the portals. So, we don't know what other effects the portals are having on physics. As you cannot get stuck in a portal it is reasonable to assume that the portal is doing other activities than just making a hole into space.

Well... it is just a video game.

Therefore it is made to entertain, not inform.

Well, I have yet to take physics, but I know that gravity doesn't move, really.  This would inhibit its ability to go through a portal.  The time one however, has me completly lost.

Actually, Rosendoom, gravity kinda does move. This is one of the things that makes physics awesome.

Theres a kind of law, or rule of thumb really, that no information goes faster than light *. So, the information "This object just got more massive" can't go faster than light. So, the increased gravity of a more massive object sort of spreads out like a wave (at lightspeed) which isn't felt until it reaches you.


(* except, we're starting to find some really freaky stuff lately which might break that law, like quantum-entangled particles which can instantaneously "teleport" information)

Speedy thing comes in.. Speedy thing comes out.

Amiright? lol