Since the beginning of civilisation, humans have been obsessed with the future and the past. Time travel is a much fantasised notion. Many scientists have tried to build time machines, which can supposedly enable humans to move back and forth in time, the way other machines like cars and trains can help humans move back and forth in 2D space, while airplanes can enable travel in 3 dimensional spaces. Time is considered to be the 4th dimension. A machine that can move back and forth single dimensionally in time or in a 4D fashion through time and space has been an obsession with almost all physicists at some point in time.
For such a machine to be possible,, most physicists rely on the principles put forward by Albert Einstein – like time dilation, and the theory of relativity. The theory of relativity, to put it in simple language says that there are no extremes and nothing is absolute – everything is relative. For example, you may feel that the sun is moving across the sky, but it’s really the earth that’s rotating and taking you with it. Time dilation is a theory that is based on the theory of relativity – it says that when 2 people move in different speeds and in opposite directions, and each hold a clock to face the other, each will feel that the other’s clock is wrong as he will see the other clock showing time different from his own. But the fact is that neither clock is slow, both are showing the same time. This will also happen if the 2 people were stationary, but on different planets.
What physicists feel by this theory is that it may be possible to develop a machine that moves at the speed of light, and thus puts the person inside the machine in a time different from the present, although in reality, he hasn’t really moved from the place at all. Some scientists argue with this theory, saying that if such a machine were to be invented, the person would digress into a parallel universe, which will be born from the point in time when he “reaches” his “destination” through the time machine, thus getting lost completely from the present universe. This is also the theory behind wormholes – the mysterious time warps that are believed to exist in the Atlantic Ocean at the Bermuda Triangle, and one of the explanations to the mysterious disappearances of scores of ships and aeroplanes that pass over the area.
All this is extremely interesting – however the question is – why would anyone want to travel in time? We already know what has happened in the past – and even if we were able to go back and try to change things, it wouldn’t probably work out in the way we want. Again, even if we do see something useful in the future, there is no guarantee that whatever we may do after coming back to the present to change that event, we will achieve what we want. In the 1st case – imagine if you made an omelette at 10 a.m, ate it, and then entered a time machine at 11 a.m, and you go back in time to 10 a.m – the moment for you to make the omelette – you will have to do it. If you don’t, then you will not be able to go back to the time machine and bring yourself back to the present. When you entered the time machine at 11a.m, it had factored in your actions at 10a.m also. Similarly, in the 2nd case, imagine, you see that you will win the lottery for some ticket at 12p.m. You then go back into the machine and come back to the present at 11a.m. You go and purchase that particular lottery ticket. However, you had seen in the future what would have happened if you hadn’t entered the machine and taken a peek in the future– that action wasn’t counted. But now you will have gone through the machine, and so the future might have changed. These are the alternate universes the scientists talk about. So when you cannot control the generation of parallel universes, and you cannot tell what universe you have traveled to, the entire purpose of a time machine is defeated!
Moral of the story – Sit back and enjoy life. The only thing which is really yours is the time now – because it’s totally your choice what you are going to do with the moment you are living now, and your choice is going to shape your future. So stop obsessing about the past – it’s gone, and it can’t be changed; stop worrying about the future – you can’t control it. The moment you have now is precious and is very aptly, called – THE PRESENT! Enjoy it before it becomes past.