I closed it (before I saw this post, not as a response to it).

The core problem is that the "portals" are not specified in physics. We don't know how they work, because no one ever bothered to figure it out.

This causes the question to be mathematically ill-posed: what is meant by "transmit gravity"? (Especially as in a GR picture gravity is the shape of space and that is the only possible mechanism for building a multiply-connected spacial topology.)

To the questions of "almost science" or speculative questions, I think there is a place for these if they are sufficiently well defined.

Trying to think up a few example of things that are definitely "in".

• Dropping things (or people) through a bore-hole along a diameter of a planet (an old stand-by).
• The consequences of discovering a magnetic monopoles and the technological implication of the same
• Physics relating to quantum black holes massive enough to hand around for a while (The Hole Man or the Pluto solution in The Golden Globe).
• We already have a question on communication via modulated neutrino beams.

I closed it (before I saw this post, not as a response to it).

The core problem is that the "portals" are not specified in physics. We don't know how they work, because no one ever bothered to figure it out.

This causes the question to be mathematically ill-posed: what is meant by "transmit gravity"? (Especially as in a GR picture gravity is the shape of space and that is the only possible mechanism for building a multiply-connected spacial topology.)

To the questions of "almost science" or speculative questions, I think there is a place for these if they are sufficiently well defined.

Trying to think up a few example of things that are definitely "in".

• Dropping things (or people) through a bore-hole along a diameter of a planet (an old stand-by).
• The consequences of discovering a magnetic monopoles and the technological implication of the same
• Physics relating to quantum black holes massive enough to hand around for a while (The Hole Man or the Pluto solution in The Golden Globe).
• We already have a question on communication via modulated neutrino beams.

I closed it.

The core problem is that the "portals" are not specified in physics. We don't know how they work, because no one ever bothered to figure it out.

This causes the question to be mathematically ill-posed: what is meant by "transmit gravity"? (Especially as in a GR picture gravity is the shape of space and that is the only possible mechanism for building a multiply-connected spacial topology.)

I closed it (before I saw this post, not as a response to it).

The core problem is that the "portals" are not specified in physics. We don't know how they work, because no one ever bothered to figure it out.

This causes the question to be mathematically ill-posed: what is meant by "transmit gravity"? (Especially as in a GR picture gravity is the shape of space and that is the only possible mechanism for building a multiply-connected spacial topology.)

To the questions of "almost science" or speculative questions, I think there is a place for these if they are sufficiently well defined.

Trying to think up a few example of things that are definitely "in".

• Dropping things (or people) through a bore-hole along a diameter of a planet (an old stand-by).
• The consequences of discovering a magnetic monopoles and the technological implication of the same
• Physics relating to quantum black holes massive enough to hand around for a while (The Hole Man or the Pluto solution in The Golden Globe).
• We already have a question on communication via modulated neutrino beams.