The tag has no wiki summary.

learn more… | top users | synonyms

18
votes
4answers
3k views

Wormholes & Time Machines - for *experts* in GR/maths

EDIT: Further clarification in the context of answers/comments received to 20 Jan has been appended EDIT: 21 Jan - Response to the Lubos Expansion appended [in progress, not yet complete] EDIT: 23 ...
18
votes
1answer
531 views

Building a wormhole

We regularly get questions about wormholes on this site. See for example Negative Energy and Wormholes and How would you connect a destination to a wormhole from your starting point to travel through ...
8
votes
2answers
1k views

Entering a black hole, jumping into another universe---with questions

I'm quite familiar with SR, but I have very limited understanding in GR, singularities, and black holes. My friend, which is well-read and is interested in general physics, said that we can "jump" ...
8
votes
2answers
803 views

How would wormhole-based FTL violate causality?

We already have an answer why physically traveling faster than light would violate causality (the clock on board our hypothetical FTL spaceship would tick backwards to some outside observers). ...
8
votes
2answers
1k views

Is it mathematically possible for a black hole to be connected to a white hole or a worm hole?

I know that there's no evidence at this point for "white holes" however would it even be mathematically possible for a black hole to be connected to a white hole (total opposite so everything would be ...
7
votes
3answers
788 views

Gödel's solutions to Einstein's relativity equations and their consequences

Gödel gave certain solutions to Einstein's relativity equations that involved a rotating universe or something unusual like that; that predicted stable wormholes could exist and therefore time travel, ...
6
votes
1answer
636 views

Tachyonic antitelephone vs messaging through a wormhole

From the wikipedia article on tachyons: Most physicists think that faster-than-light particles cannot exist because they are not consistent with the known laws of physics.[3][5] If such particles ...
6
votes
1answer
419 views

Do spacelike junctions in the Thin-Shell Formalism imply energy nonconservation and counterintuitive wormholes?

The Thin Shell Formalism (MTW 1973 p.551ff) is used to properly paste together different vacuum solutions to the Einstein equations. At the junction of the two solutions is a hypersurface of matter – ...
5
votes
2answers
497 views

Wormholes, time travel, and time dilation

I believe I understand the "wormhole time machine" now, but still have one question regarding what happens if you enter the stationary mouth. A wormhole is created and (of course) has two mouths, $x$ ...
5
votes
2answers
412 views

Asymmetric Schwarzschild solution - unequal mass on each side

Look at any Kruskal–Szekeres coordinate plot of the Schwarzschild solution. It shows the same mass everywhere. Yet the two sides cannot talk to each other, in that no information, particles, etc can ...
5
votes
1answer
328 views

Why can't Schwarzschild wormholes exist?

So, I've recently been reading up on Schwarzschild wormholes and I've learned that they cannot exist becuase they violate the 2nd Law of Thermodynamics. What I'm asking is: Why do they violate the ...
4
votes
2answers
730 views

Are Wormholes predicted by the theory of general relativity?

Just like it predicted gravitational time dilation, gravitational lensing. What does it mean to predict something, Does it mean that we'll find wormholes in nature one day?
4
votes
1answer
690 views

Negative Energy and Wormholes

Apparently to create wormholes you need negative energy/matter. Say you had negative matter/energy, how would it be applied towards making a wormhole?
4
votes
2answers
257 views

Are we going to be able to travel trough space deforming the space-time?

I'm not talking about the speed of the spaceship. If we can deform space-time we needn't any type of propulsion. And how can the travel affect to it's pilots? Can they survive?
4
votes
2answers
344 views

Potential energy conservation in traversable wormholes

Let's say I have a tube, of large radius (about 5 - 7 meters in diameter), with traversable wormholes at the ends. The wormholes are arranged as such that if something falls inside one hole from ...
4
votes
4answers
2k views

How long would it take to travel through a wormhole?

Assuming wormholes exist and you put some matter into one, how long would it take to reach the other end versus how far apart the two ends are? Basically, by how much does a wormhole stretch ...
4
votes
1answer
439 views

Diving into a charged (Reissner-Nordstrom) Black hole

Apparently there are two event horizons in this type of black hole, where the second one is known as the Cauchy horizon. According to Carroll, if you go into the first one, you will fall until you ...
3
votes
1answer
501 views

Math and Wormholes

Hopefully this is the correct forum for this. I felt that Physics Overflow may not be the correct place. I had a student approach me ask me what kinds of mathematics goes into the study of wormholes. ...
3
votes
4answers
4k views

What is negative Energy/Exotic Energy?

So I have been researching around a little as I am highly interested in Astrophysics and I came across an energy I have never heard of before; negative energy also commonly known as exotic energy. Now ...
3
votes
5answers
1k views

Can you use a wormhole to travel through space not time?

I want to know if you could theoretically travel from your house to work via a wormhole but stay in the present day...without changing time. Kind of like teleportation but harnessing the energy of a ...
3
votes
1answer
293 views

what does holographic principle from string theory say about the possibilities of wormhole travel?

Is travel through stable macroscopic wormholes between remote points of spacetime going to be possible in a definitive theory of gravity, be it string theory or something beyond it? Physicists level ...
3
votes
1answer
336 views

non-exotic traversable wormholes and string theory

In this article it is claimed that certain type of string theory called EGBd allows for traversable wormhole solutions that do not require exotic matter. What is this EGBd model and how it fits in ...
3
votes
1answer
178 views

Going through a ring of black holes

Mathematician here with a speculative physical question -- feel free to boot me if the level isn't right. Suppose one finds, or builds, a constellation of several black holes arranged in a circle. ...
3
votes
0answers
187 views

Could the collision of two pairs of quantum entangled protons cause a temporary “wormhole”? [closed]

I recently read this article from MIT News. I then started thinking about how a particle accelerator creates a temporary microscopic black hole. My question is: If quantum entangled pair $A$, ...
3
votes
0answers
257 views

ER = EPR and Time Travel

In Maldacena-Susskind paper arXiv:1306.0533, they propose an idea of $$\text{ER = EPR}$$ the relation between the wormhole and the quantum entanglement. which ER means Einstein Rosen (ER) bridges, ...
3
votes
1answer
119 views

Moving the endpoints of a wormhole towards each other

Suppose we have a perfectly safe portal/wormhole and we place the two endpoints facing each other so that a person between them would see an endless corridor (with infinite number of herself). What ...
3
votes
2answers
107 views

Calculating the mass of a wormhole

What would for an observer be the mass of an isolated Wormhole (meaning that there is no gas and no mass of stars arround it) if the wormhole mouth oposite to the observer reflects the light of a ...
2
votes
1answer
1k views

Questions after watching the movie Interstellar [closed]

Awesome movie, but as a physics student, some questions do crop up When they travel to the watery planet, they say that 1 hour on this planet is 7 yrs om earth. How is this possible? Is the planet ...
2
votes
1answer
795 views

Would a wormhole in space look like anything at all?

In movie "Interstallar", the wormhole is elaborately depicted as a sphere, complete with explanation about why it is spherical, and as it is approached, it looks like a sphere containing fabulous ...
2
votes
4answers
202 views

Conservation of potential energy for a wormhole

So you managed to build a stable traversable wormhole. Somehow you managed to acquire the exotic negative-tension materials with sufficient densities to make it all work. Now you place opening A of ...
2
votes
2answers
141 views

How is time distributed through space?

I was greatly confused when I saw video saying that if two wormholes were separated by time instead of distance, it would allow time travel. My question is what did they mean by this statement? What ...
2
votes
1answer
99 views

What is distance and velocity regarding to wormholes?

When we talk about Physics (Einstein's) laws we use notions of distance and velocity. Take for example objects A and B. In A's base at specific moment of time there's definite distance to B and ...
2
votes
1answer
116 views

Large object is pushed through a small wormhole, what happens?

A simple question about wormholes: What happens if a large object is pushed through a much smaller wormhole? For example, what happens if I push an elephant through a palm-sized wormhole? My intuition ...
2
votes
1answer
252 views

Does the concept of a wormhole violate the law of mass-energy conservation?

If my understanding of wormholes is correct, anything that moves into a wormhole can be transported from one region of space-time to another. Consider a situation where an object of mass $m$ in space ...
2
votes
1answer
114 views

How does conservation work in wormholes?

My questions might seem naive as I haven't plunged into the mathematical descriptions, but wormholes are interesting even if I don't actually know them :) First of all, is wormhole making two ...
2
votes
3answers
235 views

Another question about wormhole traversability in General Relativity

It is well known that stable, traversable wormholes require exotic matter that violate the dominant energy conditions. For the purpose of the question, let's assume enough exotic matter can be ...
2
votes
0answers
40 views

Question about wormholes with ends moving relative to one another [duplicate]

Let's say the two ends A and B of a wormhole are moving relative to one another. If I stick a starship halfway into end A of the wormhole, does the part of the starship that sticks out of end B move ...
2
votes
0answers
92 views

Entangled event horizons

Assuming it is possible in principle to entangle the degrees of freedom of the event horizons of two black holes, and that this is something that can be done, either after the black hole is formed, or ...
1
vote
1answer
141 views

Superluminal travel without time travel

Can superluminal travel or communication be possible without leading to the possibility of closed timelike curves (CTCs) and causality violations? I have seen conflicting opinions regarding this ...
1
vote
1answer
139 views

How is a wormhole formed by spacetime surgery?

How is a wormhole formed by performing surgery on spacetime?
1
vote
0answers
67 views

How would the Casimir effect stabilize wormholes?

According to various sources, the Casimir effect could theoretically be used to stabilize a two-way wormhole because it "simulates" the negative energy exotic matter that would normally be required. ...
1
vote
0answers
69 views

Hawking radiation at the mouth of Schwarzschild wormholes

I was researching a question for another post and it occurred to me that you might expect to see Hawking radiation at the mouth of wormholes. Given the mechanism of Hawking radiation at the event ...
1
vote
1answer
72 views

Gravity through a portal [closed]

Ok, this is definitely a silly question and is partly inspired by the last 20 minutes or so of the film The Avengers, so look to that if you can't picture the situation. In the film a portal is ...
1
vote
1answer
179 views

Stress-Energy Tensor

As of recent, I've been doing a bit of self education in GR, equipped with a working knowledge of the key elements of the differential geometry in GR, and in looking at the Einstein-Rosen bridge, I ...
1
vote
0answers
71 views

Do wormholes have a side to their path through space?

In theory do wormholes have a side to their path through space? What is there at a point in line with the entry and exit, would anything look different at that point in space? Could a space ant get ...
1
vote
1answer
154 views

Wormholes and the illusion of time?

I was watching a video on Youtube by Brian Greene, "the illusion of time."http://www.youtube.com/watch?v=j-u1aaltiq4 In that video, he introduces to me the idea of a "brane," or a slice of the ...
1
vote
1answer
79 views

Travelling through a worm hole

In every documentary I've seen about worm holes, I have noticed that they usually say that according to the General Theory of Relativity, there could exist worm holes called traversable wormholes; ...
0
votes
1answer
80 views

Are Asimov's short duration spacetime “jumps” feasible? [closed]

In books of science fiction (Asimov) I saw the fancy idea of a "jump" over a space-time interval, (i.e. at superluminal velocity and for a VERY SHORT time). The result was landing in another region of ...
0
votes
1answer
48 views

Would there be forces acting on a body as it traverses space near a wormhole?

If I think of the 2D explanation of a wormhole - how it's a topology that lets the ant crawl to a different place on the folded paper - there is no hint that the ant will experience any forces on it ...
0
votes
1answer
85 views

Would a wormhole be able to move?

First, I consider the following as given: All the galaxies, solar systems and planets in the universe travel on a different route at a different velocity through space, mostly moving away from each ...