Time travel in Einsteins universe

[Gale]

I'd been meaning to post about this book a while ago. I read it before school was even out, but since i read it I've just become really interested in physics and astronomy books. So I've been reading too much to post often basically.

Anyways, 'Time travel in einstiens universe' by richard gott, i thought was an excellent book. in the beginning it has a lot of pop culture references to help introduce new concepts. i thought it explained things well with good pictures and it was easy to understand. Usually technical books really bore me, but this one actually interested me. It made me want to read more.

 

[sol2]

Van Stokum Cylinder

http://wc0.worldcrossing.com/WebX?14@177.GEuFcxicuVm.0@.1ddea281

A time machine based on an immense cylinder spinning at near-light speed. The physicist W. J. van Stokum realized in 1937 that such an object would effectively stir spacetime as if it were treacle, dragging it along as the cylinder turned. What van Stokum didn't realize is that circumnavigating such a cylinder can lead to closed time-like paths. Anyone orbiting the cylinder in the direction of the spin would be caught in the current and, from the perspective of a distant observer, exceed the speed of light and thus travel back in time. Circling the cylinder in the other direction with just the right trajectory would project the subject into the future. The van Stokum time machine is based on the Lense-Thiring effect and uses ordinary matter but of enormous density - many orders of magnitude greater than that of nuclear matter.

http://www.daviddarling.info/encyclopedia/V/vanStokum_cylinder.html

The Theory of Everything, by Michio Kaku

http://firstscience.com/SITE/images/articles/kaku/black_hole2.jpg

An infinite, spinning cylinder. This allows for time travel if one travels around the cylinder. Cosmic strings. They allow for time travel if the cosmic strings collide. A spinning black hole. This collapses into a spinning ring (not a point), so anyone falling through the ring might actually fall through a wormhole (the Einstein-Rosen Bridge) which, like Alice's Looking Glass, connects two different regions of space and time. Negative matter. If enough negative matter were to be found,then it might open up a wormhole large enough so that a trip through time wouldn't be any more jarring than a ride on an airplane. Negative energy. Similarly, an intense concentration of negative energy can also open up a wormhole. A crude version of "warp drive" can be obtained if one stretches the space in front of you and compress the space behind you via negative energy. A Theory of Everything may also help explain the sticky paradoxes found in time travel stories,such as the grandfather paradox (what happens if you kill your ancestors before you are born). Because the entire universe must be quantized, it’s possible the universe splits in half when you alter the past. The "river of time" forks into two different rivers.

http://firstscience.com/SITE/articles/kaku.asp

Will UConn physicist Ronald Mallett build the first time machine?


http://www.walterzeichner.com/thezfiles/time2.gif

Imagine then--and put aside the engineering problems for a moment--a machine big enough to walk into. As you would walk forward within the confines of the light beam, (see diagram below) you'd have the impression of moving forward, but because of the space-time vortex, you'd actually be moving backward. You could walk back through time--maybe even passing yourself as you entered the ring.

http://www.walterzeichner.com/thezfiles/timetravel.html

 

[Alliance]

I'm reading it at the moment, and I agree wiv u it's really good. I keep getting a bit confused tho, but that's probably more me than the book. The first chapter is really good anyway wiv references to science fiction and whether it could actually happen in real life. I'm on Chapter 3 at the mo (and it has to go back to the library on Thursday) so can't comment on the later chapters. If u hear bout any others in the same style, if u cud post them here, that wud b great.
Thanx
Alliance

( my fav. physics book is still How the Universe got its Spots by Janna Levin tho, but that's not about Time travel its about the topology of the Universe)

 

[Reshma]

Hey hello!

I've this book. Time travel in Einstein's Universe is indeed amazing especially the part in which there in a description of sci-fi movies involving time-travel.