My take on Time Travel

Pre-Script: A bit lengthy but interesting read...

There is no other concept that captures the imagination more than the idea of time travel -- the ability to travel to any point in the past or future. What could be more cool? You could jump into your time machine to go back and see major events in history and talk to the people who were there! Who or what would you travel back to see? Mahatma Gandhi? The construction of some ancient wonder? the life of your grand-grandparents? You could go back and meet yourself at an earlier age, go forward and see how you look in the future...regardless of the many complications involved and the paradoxes which may arise. (The most famous paradox is Grandfathers paradox) It's these possibilities that have made time travel the subject of so many science fiction books and movies. The fascination to alter the future or to have a glimpse of what lies ahead has always tempted man to bend the laws of nature, technically speaking, the space-time continuum.

I have been inspired by the following sources while writing this article on time travel

• The time machine - H.G.Wells
• A brief history of time - Stephen Hawking
  
• Terminator movies trilogy
• Butterfly effect - awesome movie !
  
• TV series like Heroes
• and there are many more.....

It is a fact that we are all time travelers. As you read this article, doing nothing more than scrolling your mouse, time is traveling around you. The future is constantly being transformed into the past with the present only lasting for a "fleeting moment". Everything that you are doing right now is quickly moving into the past, which means we continue to move through time.

Ideas of time travel have existed for centuries, but when the great Albert Einstein released his theory of special relativity, he laid the foundation for the theoretical possibility of time travel. As we all know, no one has successfully demonstrated time travel, but no one has been able to rule it out either.

Time has been defined as being the fourth dimension of our universe. The other three dimensions are of space. Time cannot exist without space and space cannot exist without time. This interconnected relationship of time and space is called the space-time continuum, which means that any event that occurs in the universe has to involve both space and time.

How to time travel?

While writers have produced some great ideas for time machines over the years, a real-life time machine has yet to be built. Most theories of time travel don't rely on machines at all. Instead, time travel will likely be done by way of natural phenomena that will transport us instantly from one point in time to another. These space phenomena, which I am not even sure exist, include:

1. Wormholes
2. Cosmic Strings

1) According to me the best bet for time travel would be - "Wormholes", if they do exist. Wormholes are considered possible based on Einstein's theory of relativity, which states that any mass curves space-time. To understand this lets think about two people holding a bed sheet up and stretching that sheet tight. If one person were to place a baseball on the bed sheet, the weight of the baseball would roll to the middle of the sheet and cause the sheet to curve at that point. Now, if a marble were placed on the edge of the same bed sheet it would travel toward the baseball because of the curve.

Here, space is shown as a two-dimensional plane rather than the four dimensions that actually make up space-time. Now imagine that this sheet is folded, leaving a space between the top and bottom. Placing the baseball on the top side will cause a curvature to form. If an equal mass is placed on the bottom part of the sheet at a point that corresponds with the location of the baseball on the top, the second mass would eventually meet with the baseball. This is one of the ways how wormholes may form, really fascinating, isnt it?

In space, masses that place pressure on different parts of the universe could eventually come together to form a tunnel -- this is a wormhole. We could then travel from Earth to another galaxy and back relatively quickly (within a lifetime). I am saying a bit quickly because hypothetically speaking, we are traveling for a shorter distance at much high speed. Why we need to travel through the worm holes at the speed of light is something that I cant put here in this blog. If wormholes could be discovered, it might allow us to travel to the past as well as the future, though there are infinite complications and intricacies involved in this mind blowing journey.

2) Another way to time travel is by using the concept of cosmic strings -which are string-like objects that some scientists believe were formed in the early universe. These strings may line the entire length of the universe and are under immense pressure -- millions upon millions of tons. These cosmic strings, which are thinner than an atom, can generate an enormous amount of gravitational pull on any objects that pass near them, just like the black holes. Objects attached to a cosmic string could travel at incredible speeds, and because their gravitational force distorts space-time, they could be used for time travel. By pulling two cosmic strings close together, or one string close to a black hole, it might be possible to warp space-time enough to create closed time-like curves.

A spacecraft could be turned into a time machine by using the gravity produced by the two cosmic strings, or the string and black hole, to propel itself into the past. To do this, it would loop around the cosmic strings. However, I read somewhere that in order to travel back in time even one year, it would take a loop of string that contained half the mass-energy of an entire galaxy. Also it has been speculated that one cant go back farther than the point at which the time machine itself was created.

Epilogue

Even if you do decide to choose any one of the way stated above for your time travel dream, be sure that it is still a distant dream. Because I feel that we should not mess up with the beautiful universe that has been created for us. Let the things go as they are. No doubt, the quest for knowledge must continue, we must understand the physics behind everything after all its the basic characteristics that separate us from other living beings on this planet. But then we must not forget that after a point, things are beyond recognition and every mathematical law breaks down, say before the singularity (just before the big bang)

And if all this has been heavy for you, let me propose another mode of time travel devised by me... yes myself ! It may sound ridiculous but then not more than the stuff above. Considering the universally accepted laws of thermodynamics, it has been proved that entropy of a system "always" increases with time. Does that mean that if we manage to decrease the entropy of a finite part of space-time, it will be teleport back to past?? Some food for thought... isn't it?

Comments, views and criticisms are welcome.