Lets say a wormhole exists with point A inside the gravity well of a star and point B in a space where there is no notable nearby mass to create a gravitational force. If one were to approach point B, would one experience gravity from the star near point A of the wormhole? Do gravitational effects 'travel' through a wormhole?
Gravitational Effects – Do Gravitational Effects Travel Through a Wormhole?
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Disclaimer: I'm not a GR expert, but this is how this question has been explained to me by other physicists before. If I got something wrong, please correct me.
The traveler does indeed not have to exert as much work to leave the gravity well via the wormhole compared to the normal route. They are not repelled from mouth A nor attracted to mouth B by any effect having to do with the gravity of the planet.
Conservation laws are preserved, however, by interaction with the wormhole mouths themselves. When the traveler enters mouth A and leaves mouth B, no work is required to raise their mass because mouth A appears to gain equal mass to the traveler, and mouth B loses it. As far as conservation laws are concerned, it's as if the traveler crashed into and merged with an asteroid in low orbit (mouth A), and then an identical copy of the traveler got assembled out of the mass of another asteroid (mouth B) and ejected in high orbit.
So, if you try to generate infinite energy by throwing something through the wormhole and then running a generator off it as it falls back down, your plans will be foiled by mouth A becoming steadily more massive while mouth B becomes steadily less massive, until mouth A collapses into a black hole.
First, Einstein-Rosen bridges probably will not let through any effects since they are unstable: they close faster than anything can pass through them, including a lightspeed signal.
However, if we use some other wormhole models then it is likely that gravitational effects can pass though.
The simplest form is when we identify two surfaces with each other, like having a disk or a polyhedron for each opening and topologically glue them together. Here the curvature is zero everywhere except for the edges, where they are infinite. This may not be an entirely realistic wormhole, but it is possible to analyse rigorously what Newtonian gravity and electromagnetism does in such spacetimes (and for weak enough fields this is likely a good approximation). The conclusion for a two-side wormhole (the linked page solves it for a more general spacetime) is that gravity does indeed emerge from the wormhole if there is something heavy on the other side.
The problem with more realistic wormholes (or at least solutions to the GR equations using exotic matter) is that there is no simple way of adding two GR solutions together. One can make arguments that if matter or charge passes through a wormhole continuity will demand that field lines will thread it, leaving a kind of residual gravity or charge. The main problem is that if these become significant compared to the exotic matter densities it is plausible that the wormhole collapses. But proving this rigorously is hard.
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First let me say that wormholes, event horizons and many other possible effects associated with collapsed stars are currently purely theoretical. We think these effects and other associated events may result from the collapse of a star with a mass in excess of the Chandrasekhar Limit
We are fairly sure we are on the right track as to what what those effects are because we use GR to predict them, and it is a theory that, so far at least, has passed every test we have thrown at it.
Unfortunately we have as yet no direct proof of these exotic effects, and experts in General Relativity (and I am NOT one of them) may sometimes disagree about the detailed physics of black holes.
Any ideas about wormholes allowing you to move to another universe, or different places within our universe, are currently predictions using the math of GR , some of which may well be correct but none of which we have any proof of, as of today.
General Relativity has been confirmed very well in "normal" situations, such as predicting the changes in orbit of Mercury, and we use it's predicted effects in GPS systems, but when it comes to extreme events, such as black holes, we are predicting what "might" happen, more than currently observing what is actually happening.
If a wormhole exists in the gravity well of a star is the same as saying, if a blackhole singularity "appears" near a star.
Well, the first thing that will probably happen is that the black hole will pull the normal star towards it, possibly creating what is called an accretion disc of material from the other star.
We are pretty sure we have evidence that this actually happens. In the worse case (for the normal star), it will be pulled apart by the intense gravity of the black hole.
Anything located at point B, will feel the effects of the black hole, and a wormhole (if such a thing actually exists) will affect anything at point B, just like a normal star would, there may not be anything much exotic about it, just ordinary gravity.
So , in that sense, will the gravity effects travel through the wormhole, is the same as saying point B feels the effects of gravity.
The "wormhole", that is the point of intense gravity, will act in exactly the same way as the Sun pulls the Earth towards it.