Wormholes

[Voyager275]

Do you think that dark matter could form them? A new theory states that the center of the Milky Way is a wormhole. Opinions?

[ouion]

Source ?

[pxi]

Quick bit of google-fu turns up this:

http://arxiv.org/abs/1307.1237 (abstract below)

Two observational results, the density profile from simulations performed in the $\Lambda$CDM scenario and the observed flat galactic rotation curves, are taken as input with the aim of showing that the galactic halo possesses some of the characteristics needed to support traversable wormholes. This result should be sufficient to provide an incentive for scientists to seek observational evidence for wormholes in the galactic halo region.

and http://www.sciencedirect.com/science/article/pii/S0003491614002395?np=y (abstract below)

An earlier study (Rahaman, et al., 2014 and Kuhfittig, 2014) has demonstrated the possible existence of wormholes in the outer regions of the galactic halo, based on the Navarro–Frenk–White (NFW) density profile. This paper uses the Universal Rotation Curve (URC) dark matter model to obtain analogous results for the central parts of the halo. This result is an important compliment to the earlier result, thereby confirming the possible existence of wormholes in most of the spiral galaxies.

Edited May 2, 2015 by pxi

[K^2]

Interior solutions that are wormhole-like are unstable. As for wormholes connecting two points in our space, we do not have a theory that makes any predictions. Creation of such wormhole requires a topology change. General Relativity assumes constant topology. It makes predictions on how to manipulate and stabilize wormholes, but not on how they can be created.

[RexProcer]

So, brand new to the website. I am a geek, and my biggest hobby is RL astronomy/space/quantum mechanics/everything else regarding the topic, so while I hate looking like a stuck-up know-it-all (I don't know it all), I know enough about this subject only to be comfortable with looking like that. Anyway, to it then.

There's a few things to keep in mind here before we go any further. First and foremost, the concept of "dark matter" is rather....obscure. As a family friend with a PHD in astrophysics put it, scientists call it "dark matter" because frankly, they don't know what the hell it is, or if it even exists. All they know is, there has to be something out there holding everything together, so they call it "dark matter". It's as much possible to see right now as it is to DIRECTLY observe a black hole (that's not possible). Secondly, keep in mind that wormholes are nothing more than theoretical science right now (while many scientists/mathematicians agree the math is solid, it's still theoretical). I mean, trying to understand how space-time would be falling all over itself is pretty hard to comprehend, even for the greatest scientific minds ever. What we KNOW, beyond a shadow of a doubt, is that, at the center of the Milky Way, there is a supermassive black hole. As far as we know, every galaxy in our universe has one, and millions of smaller ones.

So the theory that there could be a wormhole in the middle of our galaxy is, to me at least, a bit farfetched. If wormholes do exist, it would only stand to reason they would be unpredictable at least, and dangerous at most. It's an interesting theory, and I'm willing to work with just about anything, but it's going to be near impossible to prove.

[K^2]

So the theory that there could be a wormhole in the middle of our galaxy is, to me at least, a bit farfetched. If wormholes do exist, it would only stand to reason they would be unpredictable at least, and dangerous at most. It's an interesting theory, and I'm willing to work with just about anything, but it's going to be near impossible to prove.

Relax. Nobody said it's a traversable wormhole. And an untraversable one has all of the same properties as a black hole. It has an "interior" region, where all sorts of crazy stuff can be happening, which is located between two exterior regions, which can be located in different places in the same universe, or different universes. For an untraversable wormhole, the transition from exterior to interior region is guarded off by an event horizon. You can enter interior region from either side, but you can't exit. You will be stuck in the middle.

The whole idea of black holes as wormholes comes from the Kerr solution to the Einstein Field Equations. It predicts that spacetime inside a rotating black hole, and any supermassive black hole is a rotating one in practice, has multiple regions, the most "interior" one stretching out to infinity and working as a whole universe. In effect, it's not "inside" the black hole at all, but rather on the other side of a wormhole.

What's even more interesting, if a black hole rotates fast enough, Kerr solution predicts that event horizon vanishes, exposing a naked singularity. That also, as a byproduct, makes a traversable wormhole. Connecting our universe with the one on the other side.

Unfortunately, or perhaps fortunately, Kerr solution is not stable in the interior. It is a solution, not the solution. Last time I have checked, a stable, ground state solution to the rotating black hole was still not known. Naked singularities are still just a quirk of the theory with no practical consequence, and the only known ways to stabilize a traversable wormhole is to have negative energy densities. Same requirements as a warp drive.

[Voyager275]

There is a mathematical object that could be better. The Milky Way black hole could have a opposite white hole somewhere. Remember a white hole is the opposite of a black hole, spitting out matter instead of sucking matter in.

[RunAwayItzJack]

One thing that's always bothered me about wormholes or portals in general is how amazingly easy it would be to violate conservation of energy. For instance if you had an opening at the bottom of the ocean with massive pressure, and one at the top of mount everest with little pressure. There would be an absolute torrent of water spewing out of the wormhole at the top. Unless the wormhole "knows" how much matter+energy is passing through it I'm not sure they're possible.

[BlueCosmology]

One thing that's always bothered me about wormholes or portals in general is how amazingly easy it would be to violate conservation of energy. For instance if you had an opening at the bottom of the ocean with massive pressure, and one at the top of mount everest with little pressure. There would be an absolute torrent of water spewing out of the wormhole at the top. Unless the wormhole "knows" how much matter+energy is passing through it I'm not sure they're possible.

Traversing a wormhole affects the energy of the wormhole, conserving energy. (For a wormhole just traversing space like you're talking about. If you start talking about ones that traverse time then no energy is not conserved, however this is not a problem as conservation of energy is a result of time symmetry, which a wormhole in time would violate)

Edited May 7, 2015 by BlueCosmology

[K^2]

Not true at all. Total stress-energy is still conserved, because it is a conserved current of local Poincare symmetry. So energy conservation violations are still to within a coordinate system choice, which is true with or without wormholes.