Wormholes

[Deadmeat]

I noticed no one has brought up this topic, so I have the honour to do it.

 

I understand the principals, but I have a few questions:

 

• If a wormhole is created, it affects space and time all around it. The area around the wormhole is seemingly intact, but how does a wormhole affect everything else? I mean, can anybody else, who is not next to the wormhole feel that a wormhole is created?
  
• I understood that a wormhole dramatically decreases the distance between two points. Of all the models I saw, it makes a tunnel, but the tunnel has a certain lenght itself. But in the 1997 film "Event Horizon", they scrapped that idea and completely nullified the length of the tunnel. Can a wormhole tunnel have a length of 0? What effect does this have on the two points where the wormhole's ends appear?
  
• How can you create a wormhole? As seen in "Event Horizon" they used a fictious device that emmits gravitons. If so, how do these gravitons actually create the wormhole?
  

[ajb]

I noticed no one has brought up this topic, so I have the honour to do it.

 

By wormhole we usually mean the Morris-Thorne wormhole. The metric of of the form

 

[math]ds^{2}= - e^{\Phi(l)}dt^{2} + dl^{2} + r^{2}( l) (d\theta^{2} + \sin^{2}(\theta)d\phi^{2}).[/math]

 

[math]r(l)[/math] is the distance from the centre, but proper radial distance as measured by a someone travelling through the wormhole is measured by [math]l[/math].

 

 

• If a wormhole is created, it affects space and time all around it. The area around the wormhole is seemingly intact, but how does a wormhole affect everything else? I mean, can anybody else, who is not next to the wormhole feel that a wormhole is created?
  

 

The space-time described by the Morris-Thorne metric is asymptotically flat, That is, if you are far enough away the space-time looks like Minkowski space-time. So, when you are well away from the wormhole you will not know it is there.

 

 

• How can you create a wormhole? As seen in "Event Horizon" they used a fictious device that emmits gravitons. If so, how do these gravitons actually create the wormhole?
  

 

Wormholes need what we call exotic matter to exist. That is stuff with negative energy. It is believed that such stuff does not exist naturally.

 

However, we do have negative energies in quantum theory. It is possible that wormholes on the microscopic level exist. It maybe possible to blow these up to macroscopic scales.

 

That said, it is not fully known if such wormoles are really stable. One thing to consider is that such wormholes can be used as time machines. There is the Hawking chronological protection conjecture that states that "no time machines can be made".

 

This conjecture come from looking at quantum field theory on a curved space time. The presence of a time machine renders the theory inconsistent. This may rule out macroscopic wormholes. It is though they may "pinch off" before you can cross.

 

Unless a quantum theory of gravity says otherwise...

[Deadmeat]

What the fu.....

 

Ha ha, joking.

 

Ok, I didn't really get you there.

 

First of all, space is not a flat surface, so how does a wormhole model look then?

 

Second, I don't understand anything from those formulas. I'm only 16.

 

Microscopic levels, eh? So they work as a passage between elementary particles, like quarks? Gluons? Ok, you didn't get it.

 

Quarks are held together by The Strong Nuclear Forces. What if those "Forces" were actually micro-wormholes? Well, they act as a passageway for the extremely unstable gluons which collapse if they travel even small distances.

 

But that's just a theory. That I just made up. I know it makes no sense.

[ajb]

First of all, space is not a flat surface, so how does a wormhole model look then?

 

For such wormholes it does look like a flat surface when you are far enough away. So, gravitationally, you won't know it is there. People have discussed astrophysical signatures of wormholes.

 

 

Microscopic levels, eh? So they work as a passage between elementary particles, like quarks? Gluons? Ok, you didn't get it.

 

It is possible that elementary particles pass through tiny wormholes all the time. But this is very much just an idea as we really have little knowledge of space-time on such scales.

[Deadmeat]

Agreed, I'm too young to understand it too.

 

But what about my theory? Any thoughts on that?

[VedekPako]

Back in the late '90s, I read an article that you'd need to annihilate the mass of Jupiter to get enough energy to create a 3' worm hole.

[Leader Bee]

I'm curious,

 

If wormholes do indeed exist then how would one go about entering one? It's my understanding they appear in 3D space as a 2D object, You'd have to travel absolutely perpendicular to the wormhole surely?

[Deadmeat]

Possibly.

 

I have a question:

 

Does a wormhole only exist in 2 dimensions?

[Akhenaten2]

I should relegate wormholes to the sci-fi scripts if I were you. They only arise because of glaring misconceptions about black holes, gravity and space-time; they aren't real - in any dimensions.

[ajb]

I should relegate wormholes to the sci-fi scripts if I were you. They only arise because of glaring misconceptions about black holes, gravity and space-time; they aren't real - in any dimensions.

 

As they arise as solutions to the field equations of general relativity they warrant study even if they are not physically realised in nature.

[Deadmeat]

So wormholes are just weed inspired ideas?

[ajb]

So wormholes are just weed inspired ideas?

 

Einstein and Nathan Rosen in 1935 were the first to think about wormholes.

 

In 1987 a paper by Michael Morris, Kip Thorne and Uri Yertsever reignited wormholes. The story is that Carl Sagan asked Thorne about the possibility of traversable wormholes for his book Contact. So, they are "sci-fi inspired".

 

The interest in wormholes and other exotic space-times is really due to the idea that one should push classical general relativity to it's limit. For wormholes, we have to think about exotic matter and the possibility of time travel.

[Deadmeat]

So wormholes could be put in the same category as lightsabers? :D

 

 

Actually, wormholes and time travel are inseperable. (Didi I spell it right?)

[Airbrush]

Deadmeat, you should always take a look at wikipedia.org to see what they say about wormholes, or any other astro-cosmo concepts, and then discuss what you learned there and ask further questions. When I Googled "wormholes" the first item was wiki.

 

http://en.wikipedia.org/wiki/Wormhole