Can Einstein-Rosen bridges exist and be traversed?

[Kutt]

Do physicists know what causes an Einstein-Rosen bridge (a wormhole) to open up? Does astronomy know of any stable wormholes within the known universe? In theory, can wormholes be artificially created? And could we use these cosmic gates to send spacecraft to distant parts of the universe and so forth?

 

[Mordred]

Gravity lots of it. Wormholes were theorized as being created by black holes. So good luck using one for transport. Not to mention none have been found.

 

[phinds]

Do physicists know what causes an Einstein-Rosen bridge (a wormhole) to open up? Does astronomy know of any stable wormholes within the known universe? In theory, can wormholes be artificially created? And could we use these cosmic gates to send spacecraft to distant parts of the universe and so forth?

This is basically just science fiction stuff in terms of actual practice.

 

[Kutt]

Gravity lots of it. Wormholes were theorized as being created by black holes. So good luck using one for transport. Not to mention none have been found.

So they only exist in theory and astronomers have yet to find any actual wormholes within the known universe?

 

[Nugatory]

So they only exist in theory and astronomers have yet to find any actual wormholes within the known universe?

Correct. "The theory says they might exist" is just another way of saying "we haven't yet proven that they don't exist", so until there are some observations, there's not much reason to take the idea seriously. Indeed, the lack of observations could be considered a hint from mother nature that we aren't seeing them because they aren't there.

Of course, some astronomer somewhere might find one tomorrow... Could happen... That's pretty much what happened with black holes (the theory said they might exist, eventually observations came along)... But I'm betting against it.

 

[stevendaryl]

What I have read about such "wormholes" (if that's the same thing as an Einstein-Rosen bridge) is that they would almost instantly close up after forming, so there would be no way to use them for traveling. To keep them open would require exotic matter (matter not known to exist) that violates the "dominant energy condition", which I don't know what that means.

 

[haael]

Kerr black holes might have a traversable wormhole without resorting to exotic matter. It could be that particles entering a Kerr black hole end up in another dimension.

What is usually ignored in these speculations is entropy. When we fall into a black hole or a wormhole, we gain entropy. Symmetrically, when we travel out of a wormhole, we would have to lose in entropy.

Someone made a nice analogy for this. If spacetime is a river, a black hole is a waterfall, then the wormhole is a waterfall followed with an inverted waterfall flowing upwards. There is nothing that forbids water to flow to the sky, except the second law of thermodynamics.

So - maybe some matter (in the sense of mass) can enter another dimension via a Kerr black hole, but most probably all information it carries will be destroyed. Rather poor way of travelling, IMO.

 

[Kutt]

I read that black holes and wormholes may hold the key to unlocking the secrets of interstellar travel. Is that true?

 

[Mordred]

Again another science fiction concept. For the reasons posted above

 

[1977ub]

Again another science fiction concept. For the reasons posted above

As I understand it, the very existence of such a thing would imply time-travel, and this is yet another reason why many scientists are skeptical?

 

[Mordred]

As I understand it, the very existence of such a thing would imply time-travel, and this is yet another reason why many scientists are skeptical?

No theoretically a wormhole if such a thing could be manufactured could create a spacetime tunnel. However the sheer amount of energy that it would take would be on par with a massive star. Some of the research I've read on it suggest it would also be unstable as well as generate high levels of radiation.
The Alcubierre drive theoretically could be used to warp spacetime enough to generate FTL. However that involves a small spacetime warpage. Even on that small scale the amount of needed
energy is enormous. Their is also concern on it of generated radiation.

 

[1977ub]

No theoretically a wormhole if such a thing could be manufactured could create a spacetime tunnel.

I gather that this alone is enough to make many eyes roll, and put the whole thing into the world of sci-fi, practical energy and safety concerns aside.

http://news.ycombinator.com/item?id=4535149

 

[Mordred]

Yeah that's fairly accurate here is a link with the mathematics on the Alcubierre drive.
http://www.extremetech.com/extreme/...nihilating-whole-star-systems-when-you-arrive

the link on the bottom of the page will lead you to the paper on it.