Wolv1's questions about causality and particles

[Wolv1]

Moderator note: This thread is a merge of many similar threads on essentially the same topic, posted by wolv1.
Now, all posts have been collected in one convenient location for your reading enjoyment.
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I was wondering and doing my research for this.

 

[BenTheMan]

What do you mean "exist"?

There ARE solutions of Einstein's equations which admit CTC's (to my knowledge), but also (to my knowledge) none have been observed in nature.

So mathematically, yes. Physically, no.

 

[Wolv1]

yes,i meant in physically,what does it mean that they are artifacts?

 

[BenTheMan]

ummm who said artifacts?

 

[Wolv1]

on the wiki page,i also was told it seems quantum gravity will disprove them?

 

[Reiku]

Frank J. Tipler worked on a hypothetical time machine, which was a fast spinning ring, that would sinusoidally warp the spacetime fabric, and would experience time moving as though it was some kind of Closed-Timelike-Curve (also known as Curved-Paths).

The may very well exist in nature, but some scientists are skeptical of them. As Ben said, at the moment, they exist as nothing but solutions to Einsteins Relativity Theories.

 

[BenTheMan]

on the wiki page,i also was told it seems quantum gravity will disprove them?

Artifacts means left over from something.

And that MAY be the case. Because we don;t know the full theory of QG, we can't make any definitive statements, I think.

And don't listen to anything Tipler writes. His stuff is fringe science at best.

 

[Reiku]

He's a mathematician, professor at New Orleans University, and is well respected among his peers.

Don't listen to what Ben says. Tipler is infamous as a great mathematician, and theorist, despite some of his work revolving around theology.

 

[Oli]

Artifacts means left over from something.

Um, artifact/ artefact means something crafted surely?

He's a mathematician, professor at New Orleans University, and is well respected among his peers.
Don't listen to what Ben says. Tipler is infamous as a great mathematician, and theorist, despite some of his work revolving around theology.

If he were INfamous then he wouldn't be well respected...
And it was cylinders, not rings, that Tipler first proposed: Physical Review D 9: 2203–2206

 

[Reiku]

Slight mishap of terminology. Not the end of the world, oli

 

[Reiku]

I used to observe the model from a birdseye view, which i suppose, is what made me think now of rings, rather than cylinders.

 

[Oli]

When it directly contradicts your point...
And I think it would be more correct to say that Tipler was highly respected.
He's done the aging physicist thing and started going woo woo now...

 

[Oli]

I used to observe the model from a birdseye view, which i suppose, is what made me think now of rings, rather than cylinders.

Where did you stand to get a bird's eye view?
The proposal was for a cylinder of infinite length, which makes it sorta hard to move round to the ends

 

[Wolv1]

what are your opinions on ctc's? do you think they exist?

 

[Reiku]

When it directly contradicts your point...
And I think it would be more correct to say that Tipler was highly respected.
He's done the aging physicist thing and started going woo woo now...

I admit, Tipler has gone a bit crusty round the edges, but God Bless him. He's a fantabulous physicist. One of my favorites next to Dr Wolf.

 

[Reiku]

Where did you stand to get a bird's eye view?
The proposal was for a cylinder of infinite length, which makes it sorta hard to move round to the ends

It was a schematic Dr Bond...

 

[Reiku]

what are your opinions on ctc's? do you think they exist?

Yes, i do.

 

[Wolv1]

does not most of the physics community think ctc's will be disproven to quantum gravity?

 

[Reiku]

Not everyone in the community can even agree on what gravity fundamentally is, never mind quantum gravity theory.

 

[Wolv1]

but ctc's violate causality, and causality has not ever been shown to be violated.