Van Stokum Cylinder (Sol's Time Travelling Guide of Mandalics Origins)
(3 previous messages)Sol
- Feb 4, 2004 7:46 pm (#4 of 38)
A Primer onTime Travel
But the easiest and most plausible time machine that can be constructed is what's known as a Tipler Cylinder. The materials may be practically "exotic" and the energy requirements enormous, but according to Dr. Frank Tipler of Tulane University in 1974, the construction of a time machine is theoretically feasible. He determined that if you somehow rotate an infinitely long massive cylinder fast enough, it would also "tip" a series of light cones into a CTC. (See B) The speed at the outer surface of the cylinder, though, would have to be greater than half the speed of light. But if something were to rotate this fast, part of it would likely collapse into a singularity - an infinitely small point of space-time, usually caused by a star collapsing under its own gravity, that has infinite mass and where the laws of physics break down. And Tipler stresses, "The stability of massive rotational bodies is questionable. The energy associated with a strong angular momentum would have to be about equal to the rest-mass energy, energy so great that the accompanying centrifugal force may tear the rotating body apart."
http://www.readmag.com/Columns/timetravel.htm
Sol
- Feb 4, 2004 7:51 pm (#5 of 38)
Time Travel in Einstein's Universe: The Physical Possibilities of Travel through Time
The notion of closed timelike curves in the real world is hard to reconcile with our intuitive understanding of causality. Perhaps one can find global solutions to general relativity incorporating closed timelike curves. These, in effect, would be time machines. But it may be impossible to construct such a system in a local region of space. Theorems along these lines were proved by Frank Tipler in the 1970s. Tipler assumed that the energy density was never negative and showed that closed timelike curves could never arise in a local region without also creating a singularity. This was reassuring, as we could hope that both the singularity and the closed timelike curves were hidden behind an event horizon (although this was not part of the proof).
http://pancake.uchicago.edu/~carroll/gottreview.html
Sol
- Feb 4, 2004 7:57 pm (#6 of 38)
How to Build a Time Machne
by Paul Davies 
In science fiction, wormholes are sometimes called stargates; they offer a shortcut between two widely separated points in space. Jump through a hypothetical wormhole, and you might come out moments later on the other side of the galaxy. Wormholes naturally fit into the general theory of relativity, whereby gravity warps not only time but also space. The theory allows the analogue of alternative road and tunnel routes connecting two points in space. Mathematicians refer to such a space as multiply connected. Just as a tunnel passing under a hill can be shorter than the surface street, a wormhole may be shorter than the usual route through ordinary space.
http://www.sciam.com/article.cfm?articleID=0004226A-F77D-1D4A-90FB809EC5880000&pageNumber=2&catID=2
Sol
- Feb 4, 2004 8:01 pm (#7 of 38)
In the beginning - It's hard to grasp, but the Universe may have made itself
Gott and Li found that a time loop could have existed before the big bang without violating any laws of physics. Space would have been in a loop of time, perpetually re-creating itself. If so, the Universe could be viewed as having given birth to itself. Gott says that asking what the first event in the Universe was becomes meaningless. "Every event in the Universe could have an event preceding it," he says.
One consequence of the idea is a natural explanation for the so-called arrow of time. Theories of general relativity and electromagnetism do not rule out the idea that waves can affect events that occurred in the past. For instance, they do not forbid light from travelling back in time.
Yet in our Universe light always travels with us into the future. The reason, say Gott and Li, has to do with what would happen to waves that regressed in time in the kind of universe they envisage. "They would travel back to the epoch of the time loop and circle forever, constantly reinforcing each other," says Gott. Such a universe could not exist, Gott concludes, because the time loop would quickly become unstable.
http://cfa-www.harvard.edu/~lli/personal/html/beginning.html
Sol
- Feb 4, 2004 8:06 pm (#8 of 38)
Will We Travel Back (Or Forward) in Time? by RICHARD GOTT III
Einstein proved we can travel forward by moving near light speed. Backward requires a wormhole, cosmic string and a lot of luck
Do the laws of physics permit time travel, even in principle? They may in the subatomic world. A positron (the antiparticle associated with the electron) can be considered to be an electron going backward in time. Thus, if we create an electron-positron pair and the positron later annihilates in a collision with another, different electron, we could view this as a single electron executing a zigzag, N-shaped path through time: forward in time as an electron, then backward in time as a positron, then forward in time again as an electron.
http://www.time.com/time/reports/v21/science/time.html
Sol
- Feb 4, 2004 8:11 pm (#9 of 38)
A User's Guide to Time Travel, By Michio Kaku
Not anymore. Having examined Einstein's equations more closely, physicists now realize that the river of time may be diverted into a whirlpool - called a closed timelike curve - or even a fork leading to a parallel universe. In particular, the more mass you can concentrate at a single point, the more you can bend the flow.
http://www.wired.com/wired/archive/11.08/pwr_timetravel_pr.html
Sol
- Feb 4, 2004 8:14 pm (#10 of 38)
Time Loops
DAVIES: I happen to be reading Michael Crichton's latest book, Timeline, one of a succession of books and movies that have come out over the last few years exploring the idea of time travel — it's not a new idea, it goes back a hundred years to H. G. Wells, probably even before that. The basic idea of a time machine, already captured in Wells's original story, is that it's possible to travel in time in much the same way that you can travel in space. It's easy to imagine building such a machine, throwing a lever and propelling yourself into the future or back into the past. Wouldn't that be fun! Wells already recognized the paradoxes that would occur if it's possible to travel backwards in time, although he didn't address them especially well. Traveling forward in time doesn't involve any sort of paradox, however, so long as the time traveller can't go back again to his original time.
http://www.edge.org/3rd_culture/davies/davies_index.html
Sol
- Feb 4, 2004 8:17 pm (#11 of 38)
Posted by sol on August 20, 2003 at 12:53:42:
When Euclid Model Stops working This post is part of index.
Sol
Sol
- Feb 4, 2004 8:21 pm (#12 of 38)
Posted by sol on January 09, 2003 at 11:13:24:
GHZ Entanglement and Bell Theorem.
A brief review of the history of in todays world as we speak of Einstein's simultaneity.
Any ideas or corrections?
Sol
Sol
- Feb 4, 2004 8:27 pm (#13 of 38)
Inverse Square Law( fifth Dimensional perspective)
Posted by sol on July 11, 2003 at 06:44:02:
The Quantum Harmonic Oscillator
What is zeropoint? If we had deduced that the world is never really flat, a string a point(no circle), a straight string, in a flat brane world, GR allowed us to move from there, and consider the dynamics of?:)I hope my point is being spelt out nice and clear. And of course, simple.
Sol
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Van Stokum Cylinder (Sol's Time Travelling Guide of Mandalics Origins)