Time Travelling - One Crazy Idea !

Who doesn’t want to go to the future to see what’s going to happen to him ! Or who doesn’t want to undo his mistakes by going back to his past ! Human being have always longed to travel through time...though it has always been a fiction or myth. Yet we cannot disagree every sci-fi is based on at least some scientific explanations.

The Fiction...

There is no strong proof of time traveling in earliest history of mankind but some religious examples, folk tales and myths. For example the concept of time traveling is introduced in Islam, Hindu mythology, Budhhism. Well, they are quite ambiguous. The Quran says there are heavenly doors which are galactic shortcuts to distant places in the universe. Maybe the angels use these doors for long distance travel. Angels can accelerate up to the speed of light for domestic travel; but they use these wormholes to reach any place in the universe even faster. There is a possibility that Prophet S.A.W. used a wormhole once in the event of Isra' and Mi'raj. in Hindu mythology, the Mahabharata mentions the story of the King Raivata Kakudmi, who travels to heaven to meet the creator Brahma and is shocked to learn that many ages have passed when he returns to Earth.

The Science...

These are vague ideas of time traveling. But scientists believe that  it is possible ! How??

1. Moving Faster Than Light

According to their theory, speed is indirectly proportional to time. Higher the speed, slower the time. Some of the stars we view from earth, might not exist anymore, but because of their large distance from us, their light reaches us years later. Example: Someone many light-years away from us, might still see earth with dinosaurs!!!

As for time travel, there’s nothing concrete about it. Most of it seems that we can somehow slow it down by travelling at light speeds. By this, you will age by only 10 yrs, but when you return, the actual years passed might have been 100..This is the by far the most simple concept how one can manipulate time. It is same as the phenomenon Twin Paradox. For example if observer A sends a signal to observer B which moves faster than light in A's frame but backwards in time in B's frame, and then B sends a reply which moves faster than light in B's frame but backwards in time in A's frame, it could work out that A receives the reply before sending the original signal, a clear violation of causality in every frame. The scenario is sometimes referred to as a Tachyonic Antitelephone.

2. Intense Gravitational Field

For the passengers of th space ship, time would have become frozen. This phenomenon is termed time dilation, and it has negated our conventional understanding of time as a leisurely-flowing stream. As Macvey points out, such "relativistic travel" can theoretically take place only into the future, and not into the past. As time is being stretched, space is being compressed.

To cause time to freeze, one would need an intense gravitational field, which can be found at the margins of what is popularly called a black hole. The main difficulty consists in finding such a hole . Circle a black hole long enough, and gravitational time dilation will take you into the future. scientists agree the black hole would probably crush you, but one unique variety of black hole might not: the Kerr black hole or Kerr ring.

3. Kerr Black Hole

In 1963, Roy Kerr, a New Zealand mathematician, found a solution of Einstein’s equations for a rotating black hole, which had bizarre properties. The black hole would not collapse to a point (as previously thought) but into a spinning ring (of neutrons). The ring would be circulating so rapidly that

centrifugal force would keep the ring from collapsing under gravity. The ring, in turn, acts like the Looking Glass of Alice. Anyone walking through the ring would not die, but could pass through the ring into an alternate universe. Since then, hundreds of other “wormhole” solutions have been found to Einstein’s equations. These wormholes connect not only two regions of space (hence the name) but also two regions of time as well. In principle, they can be used as time machines.

Kerr Black Hole and worm holes are purely theoretical. Yet it’s fun to realize what would such thing lead us to ! A wild adventure of which no one knows the end.

4. Cosmic String

On the other hand Physicist J. Richard Gott introduced the idea of cosmic string in 1991. They are string like objects which are believed to be formed in the early universe. These strings may weave throughout the entire universe, thinner than an atom and under immense pressure. Naturally, this means they exerts quite a gravitational pull on anything that passes near them, enabling objects attached to a cosmic string to travel at incredible speeds and benefit from time dilation. So if we can pull two cosmic strings close together or stretch one string close to a black hole, we may warp space-time enough to create what's called a closed time like curve.

The way this works is that two cosmic strings cross paths with each other in a certain way, moving at very high speeds. A spaceship traveling along the curves could take a very precise path (several of which were worked out by Curt Cutler in the months after Gott’s publication) and arrive at its starting position, in both space and time, allowing for travel in time.Cosmic strings, if they exist, would be extremely thin with diameters on the same order as a proton. They would have immense density, however, and so would represent significant gravitational sources. A cosmic string 1.6 kilometers in length may be heavier than the Earth.

Interestingly enough, Stephen Hawking who once opposed the idea of time travelling claiming that he had empirical evidence against it; now believes that time traveling is possible. The enormous amount of work one b the theoretical Physicists within the last 5 years or so made him change his mind !! So what do you think ??