Time:- Why it is stranger than you think
This article is a part of a series of articles on Time. This is part 1/5.
Presumably everyone has heard the saying-”Time and Tide waits for none.” This saying, and our everyday experiences, seem to show that time flows, but does it really? Or is it just a frozen river? This article on time aims at answering this question, with great detail.
Experience and Time
As humans, it is in our genes to tend towards believing in our experiences. It has been a driving force in our evolution. But experience and experiments don’t go hand in hand. It happens more than often(especially in Physics,) that an experimenter gets results so shocking that they seem false at first. The universe speaks, not in experience, but in results. Results that now we call laws of physics. The universe simply does not evolve according to our intuitions, but according to space and time.
More than once, I have seen people saying that time flows by, while in reality, it simply doesn’t. What follows is the explanation.
The Frozen River
What follows may be difficult to grasp for some readers. If that’s the case, just skip ahead to the next sections, but I do suggest that you read it, since the results are stupendous.
The universe we all live in, was formed 13.8 billion years ago. From then on, it has been constantly expanding, and forming galaxies, stars, black holes, meteors and even life. Following some laws laid down by special relativity, we can use the example of the universe itself to deduce that time is frozen.
Special Relativity, in it’s most fundamental way, gives the absolute right to rule over the universe of space and time, meaning that it upholds spacetime as absolute. Another derivative, from this theory is time-dilatation.(find out more about it here!) This allows for another very unusual thing.
If we consider spacetime a loaf, then each observer, at the same moment in time, can observe different things. The moment you are reading this, someone maybe reading their school textbook, or watching their favorite show. Thus, people in the same moment of time observe different things. They have different perspectives. This means that each observer, sort of acts like a knife, to cut the loaf of spacetime into different pieces at different angles, and many observers, share one single loaf of this bread of spacetime.
If we carefully take this approach, and apply it to the universe, we can get the following loaf:-
This loaf, undoubtedly, has been cut from an imaginary angle, from an imaginary vantage point. If you look carefully and zoom in at the final slice, you can see the first bacterium that evolved on Earth from inorganic substances, Alexander the Great cross into Asia, George Washington in become POTUS, Ravindranath Tagore the first Asian Nobel Laureate, and even your grandchildren going to buy a cake for your 80th birthday.
All of us, live in spacetime, even you and I, even you and I of the future impending, and of the gone past. We live in spacetime, we live at a point in space in a moment in time.
But this doesn’t explain why time is frozen. Why, you who were enjoying the 2020 new years party some time ago are not anymore. Well, the answer is, you still are! When you were partying at the 2020 new years party, you were perhaps dancing, or chatting or even eating. But when you were dancing or chatting or eating, you were doing something at a point in space, and in a moment of time. In that very situation, you were in Spacetime. And spacetime is absolute. You cannot delete or add something in spacetime. You are still partying at that spacetime, and its spacetime that has moved, not time itself. After all, you went home after the party at a later time and slept in your bed at a time even later. Thus, absolute spacetime prevents time from flowing. Time is not a river, it’s a frozen river, that sort of changes it’s jungle(aka spacetime) in different situations.
But that does not still explain why do eggs, which have just fallen, don’t entirely freeze mid air, or why is time in the past different from time in the future. This is something I will explain in the next article:- Time- symmetry and the arrow.