Topology and Constraints

Wheeler and Feynman (1949) were the first to claim that the fact that nature is continuous could be used to argue that causal influences from later events to earlier events, as are made possible by time travel, will not lead to paradox without the need for any constraints. Maudlin (1990) showed how to make their argument precise and more general, and argued that nonetheless it was not completely general.
Imagine the following set-up. We start off having a camera with a black and white film ready to take a picture of whatever comes out of the time machine. An object, in fact a developed film, comes out of the time machine. We photograph it, and develop the film. The developed film is subsequently put in the time machine, and set to come out of the time machine at the time the picture is taken. This surely will create a paradox: the developed film will have the opposite distribution of black, white, and shades of gray, from the object that comes out of the time machine. For developed black and white films (i.e. negatives) have the opposite shades of gray from the objects they are pictures of. But since the object that comes out of the time machine is the developed film itself it we surely have a paradox.

However, it does not take much thought to realize that there is no paradox here. What will happen is that a uniformly gray picture will emerge, which produces a developed film that has exactly the same uniform shade of gray. No matter what the sensitivity of the film is, as long as the dependence of the brightness of the developed film depends in a continuous manner on the brightness of the object being photographed, there will be a shade of gray that, when photographed, will produce exactly the same shade of gray on the developed film. This is the essence of Wheeler and Feynman's idea. Let us first be a bit more precise and then a bit more general.

For simplicity let us suppose that the film is always a uniform shade of gray (i.e. at any time the shade of gray does not vary by location on the film) The possible shades of gray of the film can then be represented by the (real) numbers from 0, representing pure black, to 1, representing pure white.

from Stanford Encyclopedia of Philosophy

From Wikipedia, the free encyclopedia.

John Titor is the name of a purported time traveller from the year 2036. He posted on several time travel-related Internet bulletin boards during 2000/2001. A notable feature of Titor's claims is that they are literate, elaborate, evocative, and reasonably consistent; they are even accompanied by photographic evidence. As a result, many have come to believe his claims (especially in the pseudoscientific community); however, many who are more skeptical hold that his claims are a hoax or possibly an example of kookery, and still others are taking a "wait and see" approach until there is definite evidence one way or the other.

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sun, hydrogen, sunshine, gold, plant with a one year life cycle, driving wheel on locomotives, here live bad-tempered people, chimneys, towers, high structures in general,archangel Michael, a center, I have gone home, creative spark of divine consciousness, life energy, heart, blood circulation, backbone, men, leaders, father.

sun, moon, eyes, mouth, pupil of the eye, human spirit, inner individual, eternal, endless, all possibilities, nothing, no possibilites at all, full moon, clear sky, town, community, center of communication, measuring instruments, electric motors,oxygen, alum,center of rotation, female sex, selector, power off, here you get nothing, here you must take care, this is a hospitable house.

tumble-drying or can be tumble-dried, understation with rotating machines.

atom, uranium, plutonium for nuclear bombs, nuclear research, nuclear physics, nuclear reactors.

nothing, zero, absence.

married, new moon, cloudy weather, overcast sky, communities, towns, centers of communication, coal, recording control.

water.

Quote:

Time and space have fascinated man since the dawn of civilisation. People have spent aeons thinking about these concepts and the ideas behind them. The Greeks, the Romans, the English, all have stared at the heavens and wondered. And not without reason! As the boundaries of physics are pushed back and back it is becoming clear that whoever understands the laws of physics best will be able to travel through time and space, easily gaining a dominant position in the known Universe. Indeed that race which can move from universe to universe will get to control all universes! We must therefore double our efforts to ensure that it is we and not some other race who gains understanding first! Or we will end up playing second fiddle for rest of time!

free code for timetravelling

hello, where am i?

Snapshot taken of the tiniest time interval The attosecond (10-18 s), also known as a quintillionth of a second, is the timescale of atomic events. In Niels Bohr's 1913 model of a hydrogen atom, it takes about 150 attoseconds for an electron to orbit the proton.

Quote:

The Universe Could Be Funnel-Shaped At an extreme enough point, you would be able to see the back of your own head. It would be an interesting place to explore - but we are probably too far from the narrow end of the horn to examine it with telescopes. from: Frank Steiner’s Quantum Chaos group