We have all seen those science fiction movies where time travel is real, where time and space know no boundaries. And where scientific laws as we know them don’t exist. We watch those movies and our minds cannot comprehend how we as a human race could possibly travel back and forth in time. As thrilling as these movies are to watch, we finish watching them and carry on with our lives. Most of us don’t think to explore the topic of time travel more in-depth.
There are many contrasting opinions surrounding this topic. However, the general consensus with much scientific proof and explanation is that time travel is not possible in the sense of using a time travelling machine. It is said that if time travel was real, we would already be doing it as a human race. However, people don’t really know for sure.
Below are a few theories and ideas pointing either to or against time travel.
Laws of physics
There have been various scientists throughout time who have played an integral part in discovering the way in which the world works. This has been life changing as we now know much more about our universe compared to thousands of years ago. We now know that the world is a sphere (although there are still many people out there who believe the world is flat) that rotates and has a gravitational pull that keeps us all from literally falling off the face of the planet. This has all been influential in the debate regarding whether or not we can time travel.
Stephen Hawking, a theoretical physicist, cosmologist, and author, believed in time travel more than he believed in the existence of God. His ‘M theory’ suggests that there may be 7 hidden dimensions on top of the 4 dimensions of space and time. Stephen Hawking was very vocal about the fact that humans would be travelling through time within the century.
In June 28, 2009 at University of Cambridge he famously threw a party for time travellers from the future. But he sent out the invitations to them only after the party. He has provided the precise GPS coordinates to avoid any confusion if anyone got lost while traveling through time and space. Only those who could travel back in time would be able to attend. Unfortunately, no one has attended the party. Nonetheless, below are a few different ways in which we could time travel.
Different ways to time travel
Velocity
If we wanted to send someone into the future, we would have to facilitate a way in which they travel into time at the speed of light, or utilize the intense gravitational pull from a black hole. As a human race, we are not yet that technologically equipped, which brings me to my next point regarding time travel.
Special relativity
Albert Einstein, one of the most influential scientists, discovered a theory known as special relativity. This basically means that time slows down as one moves faster through space approaching the speed of light. Traveling at the speed of light would make it stand still and traveling faster than the speed of light would reverse the time.
In the other way, Einstein stated that the closer an object moves towards the Earth’s core (where its gravitational pull is at its strongest) the slower time will move for that object. In this way, one could argue that time travel is real as there could be two different entities experiencing time differently, with one moving faster than the second one. This is also known as time dilation and is evident in GPS satellites that are said to gain an average of 38 microseconds per day. This is due to these satellites being situated 20,200 kilometres above the earth’s surface.
Therefore, it is quite clear that the only type of time travel that we can manage as a human race is 38 microseconds into the future due to gravity. In this way, we can use the idea of speed to travel into the ‘future’.
General relativity
Albert Einstein was also the father of this theory – wormholes, stating that the stronger a gravitational force is, the slower time will feel. In this way, one could, in theory, also experience time travel. The gravitational pull would need to be extremely strong for this to occur.
Suspended animation
Now, this form of time travel is a little vague and less scientific by itself. If you could trick your brain into changing your perception of time by slowing your entire being down, you could experience some form of time travel. An example of this would be Grizzly Bears that hibernate during winter. This enables bears to slow down the rate at which they burn energy and as a result, slow down their need for feeding. This, however, cannot yet be transferred to us humans.
Scientists have now come to know that space and time are much more similar to one another than they had previously thought. The argument then unfolds that if we can move back and forth in space, then why would we not be able to do the same thing in time.
Time is linear
Second law of thermodynamics
The second law of thermodynamics states that entropy can only increase – in layman’s terms, you cannot undo the process of making jelly, or coffee, for example. As an entity progresses, it becomes more and more disorderly. Thus, highlighting the fact that we cannot go back in time to undo our existence or change history.
Paradoxes
We as humans are extremely curious creatures. We like to know why things happen the way they do, and if there is anything we can do to change the way in which they work. Basically, we are always trying to find the best way in which to manipulate our environment. Within the ‘time travel debate’, two different paradoxes have surfaced.
Grandfather paradox
This paradox states that if one could time travel back into the past and kill one’s grandfather, one’s existence would then, as a result, be wiped off of the face of the planet. This is where we start to question the thought of ‘cause and effect’. The concept would become extremely complicated and potentially unfathomable and contradictory.
Twin paradox
Say you have a twin. One of you decides to travel into space, and the other one of you stays on earth. This paradox then states that the twin who has stayed on earth will be older than the twin who has travelled into space. This is due to the force of gravity and experiencing time in different manners. This, in itself, is a form of time travel.
In one paradox (grandfather paradox) time travel becomes contradictory and impossible as you are travelling back in time, and in the other (twin paradox) time travel becomes possible, but only into the future and only because of experiencing strong gravitational pulls which cause us to experience time in a slower way.
Conclusion
As a result, although the phenomenon of time travel is one that has intrigued us for over a century, it is more complicated than simply building a time machine and going back in time to undo a disastrous act, or into the future to meet your grandchildren. Time travel can happen, however, but only on a nanoscopic scale. We are lightyears away from figuring time travel out!
