# Moving the endpoints of a wormhole towards each other

Suppose we have a perfectly safe portal/wormhole and we place the two endpoints facing each other so that a person between them would see an endless corridor (with infinite number of herself).

What would happen if the distance between the two event horizons was decreased, I mean we move the endpoints towards each other. I imagine something like this: https://d24w6bsrhbeh9d.cloudfront.net/photo/aOqyvvR_460sa.gif

• Would a person standing in between be crushed to death by herself?
• What if the distance is infinitesimally small? What would happen to the matter trapped in between?
• Is this question even reasonable? I am not a physicist, only heard about wormholes (and-the-like) from sf and some educational books.

Source of the idea: https://9gag.com/gag/aOqyvvR

(please correct the tags if they are inappropriate)

• Nice speculation about Valve game mechanics :) – rook Aug 30 '13 at 12:31

Now you're thinking with portals! :P

The question is whether it's a wormhole or just a portal? The distinction being that the wormhole would have its own internal length, while a portal would be completely flat.

If it's a wormhole, then the two ends of the wormhole would be pressed together and you would just have a tube like space inside that curled around on itself. So long as that internal volume was big enough to contain the person, they would be fine (as long as they didn't run out of oxygen).

If it's just a portal, then the portal can't actually contain anything, and so the person in between would be crushed. Think of it like this: Stand in front of one portal and put your hand through it, onto your back. As the portals get closer together, your arm starts pushing harder into your back. Eventually you have to bend your arm so as not to put your hand through your own back, but eventually that's not enough and your arm is completely pressed up against your back. This sort of thing is happening across the entire face of the portal, and so you would be squished to death.

If the distance is infinitesimally small, then you'll still be crushed to death, because I don't know anybody who can exist in an infinitesimally small space. The matter, however, will occupy the space so long as it can fit. The result of what's going to happen is virtually the same as if the two surfaces didn't have a portal at all, and were being pushed together.

Personally I think this question is a perfectly reasonable one because, if nothing else, it's fun to think about.

• and then a black hole would form, right? – Armadillo Jul 31 '15 at 16:31
• No. Black holes form when an object's gravitational pull is stronger than its own internal forces, and so it collapses in on itself, to the point of having infinite density. That's not what's happening here. – MattS Aug 28 '15 at 10:12
• Interesting. So an object with little gravitational pull can be forced to a point of having infinite density an not create a black hole? – Armadillo Aug 28 '15 at 15:50
• If it has little gravitational pull, then it has little mass. Black holes require a certain amount of mass before they can form. – MattS Aug 28 '15 at 19:15
• Thanks for clearing that up! Simple Rewording to avoid confusion for future readers: Q:Can an object with little gravitation pull be forced to a point of having infinite density and not create a black hole? A: Yes – Armadillo Aug 28 '15 at 20:07