Is it or isn’t it…who really knows?
Most of us probably don’t dare to believe that time travel is possible, but I think this is changing! The understanding of the science behind time travel is getting better understood, and an increasing number of scientists are now finding ways which one day might unlock the mystery of the time machine blueprint. The hard study and the calculations continue.
But even if we don’t know how to travel in time now…that doesn’t mean it’s impossible…does it?
Why isn’t time travel impossible?
There are so many paradoxes associated with time travel that you could well be forgiven for thinking that time travel is not possible. The “grandfather paradox” – where you go back in time and kill your grandfather (why would you do that?!) thus preventing your own existence to go back and kill him in the first place is perhaps the most famous of these paradoxes.
Or if time travel was possible, surely we would have met time travelers who have come to our time from another time by now?
Grandfather paradox? It’s all relative!
So on the face of it, it would seem that the idea of time travel is just that…an idea. It has certainly captured the attention of many science fiction authors, and even poets. And recently…scientists. Yes, there have already been many eminent scientists who have gained funding for looking into the possibility of time travel – and to find a way to make it happen. They do this by turning to Einstein’s theory of relativity.
Einstein’s theory of relativity is used to describe our understanding of time and space. Actually, time and space are so heavily intertwined that they are referred to collectively as “timespace” as one affects the other. By studying the theory of relativity, scientists hope to discover a solution to its equations which permit time travel. So has there been any success?
Interestingly, success has been found in the opposite sense…that is to say that nothing has been found which forbids time travel. So that is good news for those of us who would like to travel in time – though we are still no closer in finding out how we can do this. Or are we?
The theory of relativity describes “time dilation”. Time dilation refers to how a second of time can take longer in some situations than in others. This is slightly different to the perception of time which Einstein himself has been quoted as saying “When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That’s relativity.”
Here’s an example of time dilation. There are 2 identical clocks. Let’s call then clock A and clock B. Clock A is put on a jet plane, whilst clock B stays on the ground at the airport. The jet plane takes off, travels at high velocity around the world and lands back at the airport. The times on the two clocks are compared…clock A (the clock which was on the plane) shows that less time has elapsed than shown by clock B at the airport. Why? Because travelling at speed causes time to slow down. That is time dilation.
Another example of time dilation is seen in the satellites used in GPS navigation. In this case, there are two causes of time dilation. The first is the high speed relative to the Earth at which the satellites travel, and the second is the decrease in gravitational potential the satellites experience in orbit. The clocks on board the GPS satellites actually need to be corrected for the effect of time dilation!
The existence and reproducibility of time dilation is a good step towards realising the possibility of time travel. But are we any closer to making our time machine?
Faster than light
Perhaps. Experiments have been conducted which have shown that faster than light speed travel might be possible with some sub atomic particles and arguably this is a step in the right direction for moving on towards building a time machine. However, the energy input required is astronomical, and to reiterate…this was only a sub atomic particle! Perhaps the understanding of an alternative theory of timespace would show a solution to time travel where the energy requirement is not a practical limitation.
Conclusion: the answer is…
Having said that the subject of time travel is now receiving more attention from scientists, that is not to say that all scientists are in support of the existence of time travel. Many scientists have discredited the idea entirely, and it is clear that the question of whether time travel exists or not is still a topic of hot discussion.
So is time travel possible?
I think that presently, it is not possible in the way that we would like it to be – the days of the fabled time machine are far away. I do hope that one day in the future we will be able to travel back to the past, or into the future and experience other times just as we can experience and enjoy the present, though at the same time I am cautious about the possible dangers. Many of us are still not able to navigate safely through space (just think of all of those road accidents…) and I’m sure that navigating through time is a much more complex issue.
And we still don’t know about those time travel paradoxes…
Thankfully, even if real life time travel doesn’t exist, we can still read about it in science fiction!