Time dilation, as a mathematical concept, is tough to grasp. But thankfully, it can be explained in simple theoretical terms. Dilation, as you might know, is the process of becoming larger and/or wider. Thus, time dilation is basically the concept of widening the length of time itself! Oh yes, time can be stretched or compressed on a whim, and time travel is actually possible!
Back at school, you would have learned that there are three basic dimensions: length, breadth, and height (alternatively length, width, and depth). Any earthly object can be thoroughly described by these three dimensions. However, the likes of Minkowski and Einstein managed to identify the existence of a fourth dimension – time! This immense realization utterly transformed the way we looked at things.
For instance, before Albert Einstein’s Theory of Relativity, we used to consider that time was an absolute entity; it simply could not be altered (that is, time will be the same for a stay-at-home housewife and her husband traveling to work in a car). But after the Special and General Relativity theories were established, we started looking at time in a new light, with the help of the speed of light!
In fact, the Relativity theory shows that time slows down for a person in motion with respect to another person who is stationary. Thus, the husband from our previous example will experience fractionally reduced time the faster he travels in his car, showing he alters time more and more the faster he drives. However, I think I’m getting ahead of myself here! Let us try to understand the basic concept of time dilation first.
What is Time Dilation?
Time dilation is basically the difference in the time elapsed between two different objects, one of which is traveling at a certain speed, while the other lies stationary. Alternatively, gravity also affects the time difference between two objects, with time moving slower for an object affected by gravity than the time elapsed for another object which has no gravitational pull whatsoever. However, it takes the object to be traveling at near the speed of light or lying close to a black hole to actually measure the time difference!
To explain further, just as the length, breadth or height of a steel block can be increased by adding more steel to its edges, the block’s time (the fourth dimension) of corrosion can be extended by adding more speed or the gravitational potential to it. This is what time dilation is all about! The faster an object travels through space or the greater the potential of gravity that acts on it, the lesser will time pass for it with respect to a stationary or gravity-less observer.
Thus, if you were traveling in a car that runs at say about 10% of the speed of light (about 29 979 245 meters per second; impossible, I know! Hence the ‘If’), then you will age at a much lesser rate than all the other earthlings. Meaning that you will live longer, several years longer! Don’t try to do this in person though! Our good old cops will ask you to pull up your vehicle soon after you exceed 80 kmph speeds. If not, then you will just die when the car explodes to smithereens once you try to exceed its maximum speed of about 240 kmph. Bah!
Example to Understand The Time Dilation:
Let us, instead, take the example of a cricket ball, a relatively safer option. The fastest ball ever bowled in the history of the game was by Shoaib Akhtar in 2003, clocked at 161.3 kmph.
Now, imagine that a mosquito wearing a miniature timer is sitting pretty on a cricket ball lying on the field. This timer is perfectly in sync with the watch strapped to the umpire’s wrist. The year is 2003, and Shaoib Akhtar is about to bowl the fastest ball. He picks up the ball (with the mosquito on it) from the field, makes his long run, and releases it. As soon as the ball is released, both the mosquito and the umpire start their respective timers. Let us assume that the England batsman (who had gracefully played the ball) doesn’t play it but leaves it to run its course. Even the wicketkeeper leaves the ball and it manages to travel at the same speed of 161.3 kmph for around 490 yards (0.448 kilometers).
At that very moment, the umpire records the time to be 1 second, but the mosquito finds that the time on its watch hasn’t even crossed half a second; in fact, the creature would record a time of around 0.449 seconds! Thus, essentially, the mosquito would have traveled over half a second into the future after the ball stops! This shows that the time is dilated for the stationary umpire in comparison with the fast-moving mosquito.
Time dilation is a fascinating concept, to say the least. Who doesn’t want to travel to the future after all! However, did you know that the fastest we have managed to travel, thanks to unmanned flight, is just over 21,000 kmph (far less than relativistic light speeds), and the nearest PROBABLE black hole is about 3000 light-years away? Hence, at the moment at least, traveling to the future is still a thing of the future. We can only wait for it to come!