3 ms·

> An even bigger problem seems to be producing the wormhole in the first place. It would be interesting to understand whether they can be produced in the RS mod

> An even bigger problem seems to be producing the wormhole in the first place. It would be interesting to understand whether they can be produced in the RS model. Since they require topology change, this seems difficult. Has there been any serious (or at least semi-serious) thought given to this? I've perused some literature on wormholes, and it seems like even if you can somehow handwave away the GR energy conditions, the causality violations, etc., when talking about wormholes, everyone's always stuck on the issue of getting one to begin with. Do we know anything about whether the topology of spacetime can be changed?

grawprog 6y ago
A few results from a quick search on changing the topology of spacetime. There was a bunch more. It seems to be an area of research anyway. https://arxiv.org/abs/1212.3000 https://arxiv.org/abs/1212.3000 https://arxiv.org/abs/hep-th/9311186 https://arxiv.org/abs/hep-th/9311186 http://adsabs.harvard.edu/full/1997BASI...25..571B http://adsabs.harvard.edu/full/1997BASI...25..571B
zamalek 6y ago
So far as changing the topology of spacetime, NASA is (or was) investigating it as part of Alcubierre/Warp drive research[1]. That being said, a warp bubble is a far simpler goal than a wormhole. > According to White, these results showed a vanishing but non-zero difference between charged and uncharged states after signal processing, but this difference remains inconclusive due to external interference and limits in the computational processing. [1]: https://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_interferometer https://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field...
- enchiridion 6y ago
  Isn't that changing the geometry, not the topology?
- qubex 6y ago
  The Alcubierre Drive does not change topology (number of shortest paths), only geometry (lengths of the shortest path).
6gvONxR4sf7o 6y ago
Follow up question: When a black hole is created, is that a change in spacetime topology?
- techdragon 6y ago
  Topology basics would tell me that fundamentally at least as far as a simple overview goes... a “black hole” doesn’t imply a topological change however a “wormhole” does imply a topological change. One “punches through” the otherwise “flat” space time, creating another “opening” in the surface and increasing the complexity of that space time surface. To use the proper topology related words... The presence of a wormhole would make a region of space time that contained both ends of that wormhole, non-homeomorphic with that same region of space time without the wormhole. A black hole would not affect how homeomorphic the two regions of space time are, therefore it’s not really a change in the “topology” of the space even if the black hole would definitely change the geometry of that space quite drastically.
qubex 6y ago
A highly nontrivial issue connected with the change of topology associated with wormholes is whether passing through a wormhole reverses chirality or not.

grawprog 6y ago

A few results from a quick search on changing the topology of spacetime. There was a bunch more. It seems to be an area of research anyway. https://arxiv.org/abs/1212.3000 https://arxiv.org/abs/1212.3000 https://arxiv.org/abs/hep-th/9311186 https://arxiv.org/abs/hep-th/9311186 http://adsabs.harvard.edu/full/1997BASI...25..571B http://adsabs.harvard.edu/full/1997BASI...25..571B

zamalek 6y ago

So far as changing the topology of spacetime, NASA is (or was) investigating it as part of Alcubierre/Warp drive research[1]. That being said, a warp bubble is a far simpler goal than a wormhole. > According to White, these results showed a vanishing but non-zero difference between charged and uncharged states after signal processing, but this difference remains inconclusive due to external interference and limits in the computational processing. [1]: https://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_interferometer https://en.wikipedia.org/wiki/White%E2%80%93Juday_warp-field...

enchiridion 6y ago
Isn't that changing the geometry, not the topology?
qubex 6y ago
The Alcubierre Drive does not change topology (number of shortest paths), only geometry (lengths of the shortest path).

6gvONxR4sf7o 6y ago

Follow up question: When a black hole is created, is that a change in spacetime topology?

techdragon 6y ago
Topology basics would tell me that fundamentally at least as far as a simple overview goes... a “black hole” doesn’t imply a topological change however a “wormhole” does imply a topological change. One “punches through” the otherwise “flat” space time, creating another “opening” in the surface and increasing the complexity of that space time surface. To use the proper topology related words... The presence of a wormhole would make a region of space time that contained both ends of that wormhole, non-homeomorphic with that same region of space time without the wormhole. A black hole would not affect how homeomorphic the two regions of space time are, therefore it’s not really a change in the “topology” of the space even if the black hole would definitely change the geometry of that space quite drastically.

qubex 6y ago

A highly nontrivial issue connected with the change of topology associated with wormholes is whether passing through a wormhole reverses chirality or not.