Could we really leisuretriptips through time? The short answer is yes! That’s right. We all have the ability to leap forward through time, even if we don’t realize it. If you wanted to jump to the future, you can simply go to sleep and wake up a few hours later right? Of course that’s cheating the question. We want to be able to go back and redo those silly mistakes we made many years ago. who doesn’t wish they could go back and talk to their 15-year-old self? Tell them not to make the mistakes you did (or they will). Or perhaps you’d rather travel 500 years into the future and see those flying cars we were promised by the year 2000. Fortunately, time travel is theoretically possible.
In fact there is no law in physics that prevents time travel. That’s right, according to all the laws of physics we know, it’s perfectly plausible to travel through time at will. But as the saying goes, with great power comes great responsibility. Time travel is an extremely dangerous endeavor with devastating consequences, and is also riddled with paradoxes.
For example, what if I travelled back in time and prevented World War II? Sounds like a brilliant idea right? Countless lives would be saved, I’d be hailed as a hero! Not necessarily. Although I’d be saving lives, I’d also be destroying others. What about all the technology that we rely on today that was developed during the war, such as jet engines and nuclear power. In fact the world map could be completely different. We could actually be worse off than simply leaving history as it was.
Another famous time travel paradox is the grandfather paradox, which basically states that if we were to say for instance, I travel back to a time before my parents were born and prevent my grandfather from meeting my grandmother. My parents couldn’t have met and thus, I would never have been born. So how could I have gone back in time to prevent my grandparents from meeting in the first place.
So we can see that time travel could be a bad idea, but let’s say we really want to go back in time, how would we do it? Well first we need to understand how time works.
Time is something we are all very familiar with, we all know what it is, but yet we can’t see it, touch it, we can’t seem to interact with it in any way, we can only observe it. Isaac Newton thought that time was constant and never deviated, which would of course make time travel impossible. Even Einstein believed it was impossible, yet it is his equations that make it possible. Einstein theorized that space and time are inexplicably linked in what he refers to as “space-time”. So in theory, if I was to warp space with something extremely powerful like a black hole, I would also be warping time. While this appears to be true and scientists continue to explore its possibilities, the real possibility for time travel, seems to be in his other theory; Relativity. In fact time travel using relativity isn’t just a theory, it’s actually been done, several times! Now you probably think I’m crazy but the secret seems to be in going extremely fast.
According to Einstein’s theory of general relativity, no object with mass may travel faster than the speed of light, which is an astonishing 299,792,458 metres per second in a vacuum (that’s no air). That’s an incredible 1,080 million kilometres an hour! So according to General Relativity, we can only travel at 99.99% the speed of light. But lets say for instance that I’m sitting at the back of a plane travelling at the speed of light and I walk to the front of the plane from the back at a rate of 10 kilometres an hour. I’ll leave the equations out of this, but that would mean that my speed plus the speed of the plane would mean that I’m travelling at 1,080 million and ten kilometres an hour, which is 10km/h faster than light, right? Wrong. According the theory of relativity, time would actually slow down for me to prevent me from travelling faster than light. Sounds weird doesn’t it.
