4 ms·

When the call a wormhole "traversable" does this mean that an macroscopic object can actually survive a wormhole intact? Or are the referring to something more

by mankyd 9y ago

When the call a wormhole "traversable" does this mean that an macroscopic object can actually survive a wormhole intact? Or are the referring to something more along the lines of a sub-atomic particle? edit: the article eventually starts talking about "qubits" explicitly, so I am assuming this is sub-atomic particles only unless someone knows more. Even more specifically, it says that which falls into A comes out of B as Hawking radiation. You can then transfer an external message (at the speed of light) between A and B to turn that Hawking radiation into the original object via hand-wavy quantum teleportation. I get the feeling that you'd have to trap _all_ of the relevant, escaping radiation from B to actually reconstruct your object.

QAPereo 9y ago
Definitely the latter, “traversible” means “in principle”
dogma1138 9y ago
From what I understand they are describing a mechanism through which information can escape black holes. The problem with black holes is that a classical black hole would result in loss of information which is a big no no. The initial proposal for Hawking radiation lacked a mechanism through which information can escape the black hole this wormhole of sorts provides this mechanism. I’m not entirely sure how different it is to the holographic principle in which the information is encoded on the surface of the black hole which allowed the Hawking radiation to “pick up” a bit of information on its way back sort of like light projector.
- pdonis 9y ago
  > From what I understand they are describing a mechanism through which information can escape black holes. A hypothesized mechanism. None of this has any experimental confirmation, nor is any likely any time soon. It's an interesting theoretical advance, but that's all.
  - dogma1138 9y ago
    Yes everything here is theoretical including the Hawking radiation itself.
- mojomark 9y ago
  > I’m not entirely sure how different it is to the holographic principle in which the information is encoded on the surface of the black hole... Kind of off topic, but once I learned about the holographic equivalency of black holes, and the idea that our entire universe may be nothing more than a hologram on a 2D surface, it always seemed plausible to me that the expansion of our universe could be thought of as actually an accelerating shrinkage. In other words, if you imagine the universe as a 2D membrane of fixed size, but ever-increasingly complex holographic encoding on the membrane, then the 3D projection of that encoding would appear to be expanding (from the perspective of someone inside the hologram) relative to the fixed membrane size. However, from an outside observer, the 3D projection would appear to be shrinking as the hologram grows more complex. I realize that this metaphysical idea implies information is being constantly created to fuel the increasing complexity of the hologram. In my mind this is like propogating waves on an enclosed plane like an imperfect sphere, continually interfering with themselves on the return trip, gerating exponentially more wavelets at each encounter. Are there any theories out there like this (i.e. our universe expanding or shrinking, depending upon the perspecing of the observer)? I've always been curious.
  - dogma1138 9y ago
    I'm not attempting to claim subject matter expertise but I would like to raise two points. 1) If your hypothesis assumes that information is actually created then it's either wrong (as it's contradictory to our current understanding of physics) or you need to describe a mechanism through which information can be created or added to our universe from an external source. You might be able to contrive a mechanism through which the expansion is simply a byproduct of the every increasing entropy but I don't understand why would it then appear to an observer that the total area of the hologram is shrinking. A hologram cannot hold more data without expanding it's surface area (adding additional dimensions to a hologram to make it more complex would also impact "our universe" in this analogy), the popular science "formula" for the total information that can be stored in a hologram is basically it's information density (which has a limit) x it's surface area. Now you can say that our universe is encoded in a hologram that hasn't reached the Bekenstein bound so the information density of it can increase but again that would require some sort of a mechanism that I'm not aware off, but I'm not an expert or even particularly knowledgeable in this matter to be able to have a truly constructive discussion. 2) A theory that describes the "true nature" of the universe is useless unless it gives new predictions or new tools to explain existing phenomenon. It doesn't really matter if our universe is encoded on the surface of a black hole in another universe, is one of many bubbles of the foam that makes up the multiverse or is it one of many marbles in the marble bag of some alien teenagers from the trans dimensional universe five-nine-alpha.
ztjio 9y ago
It's important to understand when physicists talk about the theoretical perfect preservation of information in these contexts, it's like... if you could pause the universe and evaluate every particle, every "thing," all at once you could understand where it all came from and know the previous step and from there the previous step and so on infinitely until the "beginning." The idea being that the entire universe's "state" if you will, is derived continuously from its origin, observably. It's not about whether you as a human could use a black hole as a cosmic... blackboard.
- SubiculumCode 9y ago
  In an entirely mechanistic nonprobabilistic universe, where state C always follows state B, which always follows state A, etc, then if State X ever equals a prior state, say state B, then the universe enters into an infinite loop. A-B-C-D-X-C-D-X...
  - tempestn 9y ago
    That's true, but why is it important?
    - dotancohen 9y ago
      No big bang, no great crunch, Pantera will have more live shows, etc.
    - SubiculumCode 9y ago
      As constructed, it is true. But important? Probably not. Even if the universe was total mechanistic, and should be described as a series of discrete states, the probability of ever entering into identical states would be very near zero, except perhaps in some hypercooled state, or something. am not sure that the laws o thermodynamics would even allow that to happen. But I am no physicist..just a dude, who had a thought.
  - posterboy 9y ago
    I think most people wouldn't assume a discrete nature of finite state changes as I take from your comment. A cauchy series for example orbits around a limit point. Fixed states would be enumerated by Natural numbers that are extensionally defined in set theory for example as ( 0 ), [ 1, ( 0 ) ], { 2, [ 1, ( 0 ) ] }, ... Be 0 the empty set, then this is the Von Neumann construction [1]. This is a very tangible notion that represents a total order. So a state is a sequence of inputs and the natural number represents the recursion depth of the successor funtion (succ). But the complexity of that function alone is less than NP, so it would not have arbitrary consequences, so cycles would be the least of a problem. A P-adic numbers field Q_p on the other hand isn't even well ordered. Or Pi, it contains many different fixed length versions of itself in its remainder. [1] https://en.wikipedia.org/wiki/Natural_number#Von_Neumann_construction https://en.wikipedia.org/wiki/Natural_number#Von_Neumann_con... [2] https://en.wikipedia.org/wiki/Mealy_machine https://en.wikipedia.org/wiki/Mealy_machine

by mankyd 9y ago

QAPereo 9y ago

Definitely the latter, “traversible” means “in principle”

dogma1138 9y ago

From what I understand they are describing a mechanism through which information can escape black holes. The problem with black holes is that a classical black hole would result in loss of information which is a big no no. The initial proposal for Hawking radiation lacked a mechanism through which information can escape the black hole this wormhole of sorts provides this mechanism. I’m not entirely sure how different it is to the holographic principle in which the information is encoded on the surface of the black hole which allowed the Hawking radiation to “pick up” a bit of information on its way back sort of like light projector.

pdonis 9y ago
> From what I understand they are describing a mechanism through which information can escape black holes. A hypothesized mechanism. None of this has any experimental confirmation, nor is any likely any time soon. It's an interesting theoretical advance, but that's all.
- dogma1138 9y ago
  Yes everything here is theoretical including the Hawking radiation itself.
mojomark 9y ago
> I’m not entirely sure how different it is to the holographic principle in which the information is encoded on the surface of the black hole... Kind of off topic, but once I learned about the holographic equivalency of black holes, and the idea that our entire universe may be nothing more than a hologram on a 2D surface, it always seemed plausible to me that the expansion of our universe could be thought of as actually an accelerating shrinkage. In other words, if you imagine the universe as a 2D membrane of fixed size, but ever-increasingly complex holographic encoding on the membrane, then the 3D projection of that encoding would appear to be expanding (from the perspective of someone inside the hologram) relative to the fixed membrane size. However, from an outside observer, the 3D projection would appear to be shrinking as the hologram grows more complex. I realize that this metaphysical idea implies information is being constantly created to fuel the increasing complexity of the hologram. In my mind this is like propogating waves on an enclosed plane like an imperfect sphere, continually interfering with themselves on the return trip, gerating exponentially more wavelets at each encounter. Are there any theories out there like this (i.e. our universe expanding or shrinking, depending upon the perspecing of the observer)? I've always been curious.
- dogma1138 9y ago
  I'm not attempting to claim subject matter expertise but I would like to raise two points. 1) If your hypothesis assumes that information is actually created then it's either wrong (as it's contradictory to our current understanding of physics) or you need to describe a mechanism through which information can be created or added to our universe from an external source. You might be able to contrive a mechanism through which the expansion is simply a byproduct of the every increasing entropy but I don't understand why would it then appear to an observer that the total area of the hologram is shrinking. A hologram cannot hold more data without expanding it's surface area (adding additional dimensions to a hologram to make it more complex would also impact "our universe" in this analogy), the popular science "formula" for the total information that can be stored in a hologram is basically it's information density (which has a limit) x it's surface area. Now you can say that our universe is encoded in a hologram that hasn't reached the Bekenstein bound so the information density of it can increase but again that would require some sort of a mechanism that I'm not aware off, but I'm not an expert or even particularly knowledgeable in this matter to be able to have a truly constructive discussion. 2) A theory that describes the "true nature" of the universe is useless unless it gives new predictions or new tools to explain existing phenomenon. It doesn't really matter if our universe is encoded on the surface of a black hole in another universe, is one of many bubbles of the foam that makes up the multiverse or is it one of many marbles in the marble bag of some alien teenagers from the trans dimensional universe five-nine-alpha.

ztjio 9y ago

It's important to understand when physicists talk about the theoretical perfect preservation of information in these contexts, it's like... if you could pause the universe and evaluate every particle, every "thing," all at once you could understand where it all came from and know the previous step and from there the previous step and so on infinitely until the "beginning." The idea being that the entire universe's "state" if you will, is derived continuously from its origin, observably. It's not about whether you as a human could use a black hole as a cosmic... blackboard.

SubiculumCode 9y ago
In an entirely mechanistic nonprobabilistic universe, where state C always follows state B, which always follows state A, etc, then if State X ever equals a prior state, say state B, then the universe enters into an infinite loop. A-B-C-D-X-C-D-X...
- tempestn 9y ago
  That's true, but why is it important?
  - dotancohen 9y ago
    No big bang, no great crunch, Pantera will have more live shows, etc.
  - SubiculumCode 9y ago
    As constructed, it is true. But important? Probably not. Even if the universe was total mechanistic, and should be described as a series of discrete states, the probability of ever entering into identical states would be very near zero, except perhaps in some hypercooled state, or something. am not sure that the laws o thermodynamics would even allow that to happen. But I am no physicist..just a dude, who had a thought.
- posterboy 9y ago
  I think most people wouldn't assume a discrete nature of finite state changes as I take from your comment. A cauchy series for example orbits around a limit point. Fixed states would be enumerated by Natural numbers that are extensionally defined in set theory for example as ( 0 ), [ 1, ( 0 ) ], { 2, [ 1, ( 0 ) ] }, ... Be 0 the empty set, then this is the Von Neumann construction [1]. This is a very tangible notion that represents a total order. So a state is a sequence of inputs and the natural number represents the recursion depth of the successor funtion (succ). But the complexity of that function alone is less than NP, so it would not have arbitrary consequences, so cycles would be the least of a problem. A P-adic numbers field Q_p on the other hand isn't even well ordered. Or Pi, it contains many different fixed length versions of itself in its remainder. [1] https://en.wikipedia.org/wiki/Natural_number#Von_Neumann_construction https://en.wikipedia.org/wiki/Natural_number#Von_Neumann_con... [2] https://en.wikipedia.org/wiki/Mealy_machine https://en.wikipedia.org/wiki/Mealy_machine