I do not consider myself to be smart enough to answer a question that remains unanswered since thousands of years:
What is time?
Nevertheless I will answer that question now. I am asking every person smarter than me to explain to me, why my answer must be wrong. More so: There may even be some very basic mathematics below. I am very keen to find out why this mathematics is either wrong or irrelevant – or simply stupid. It sure is!
I define time as the amount of information available for a given phenomenon.
If there is a lot of information, then the phenomenon is considered to exist for a very long time. If only little information is available, the phenomenon is considered to exist for a very short time only.
For example, if a guy called Join Doe is travelling from Berlin to Moscow, there might be at least two bits of information about this:
- John Doe is in Berlin
- John Doe is in Moscow
If there is no other information available, then the phenomenon is very short lived, meaning John was traveling at maximum speed. That could be the speed of light.
But there might be more information available: John might take a stop in Minsk, because he loves a most beautiful Belarus girl at that place. It just means, that his travel speed is much slower. Far from the speed of light in this very case! So there is more time between his departure in Berlin and his arrival. It might even happen, because he is so very much in love with this girl, that he will never arrive in Moscow. In that case, the amount of time between departure and arrival is infinite.
Time can thus be seen as function of the discrete amount of available information: . We know that for any with there will always be .
But apart from that I do not really know a lot about the function .
Please note that by this definition there is no direction associated with time! So, time does not really tell us if Johnny starts his journey in Berlin or in Moscow. We can only be sure that he was in Minsk, and that he was having a great time there, wishing to stay for ever with the girl. (Maybe she also really cares a lot about him!)
Things are getting more interesting, if we – for example – consider a black hole. As we know by the theory of relativity, time “is slowing down” a bit, the nearer you get to a black hole. Now, let us look at John Doe again: Imagine this guy is getting really close to a black hole. (There is no reason whatsoever to compare his relationship with his girl to a black hole or find any other similarities or even more vulgar comparisons related to her.) Just imagine that John is attracted to the black hole just as he is attracted to his girl friend. The nearer he is getting to the black hole, the lesser are his chances to escape. A black hole squeezes a lot of matter into a tiny space, increasing its gravitational field and decreasing time in comparison to other people lucky enough to stay farer away from the black hole. (Still, please no comparisons to the girl friend!)
If John finally reaches the center of the black hole, there will be no more doubt about his very location. No longer will he be in Berlin! He will not be in Moscow, nor in Minsk. No matter how often we would request his position, we will always be sure that we could find him in the center of the black hole. Thus the amount of available information about his position has reached infinity, the uncertainty about his whereabouts has reached , and thus time will now longer flow. Time will stand still, and there will be no time at all at the center of a black hole.
As you can see, we can explain the behaviours of time in a very strong gravitational field, even without the nasty compexity of general relativity.
Let me give you another example: The double-slit experiment, seen from the viewpoint of quantum theory. As we know, getting information about a quantum system always implies doing an experiment, and the results will vary depending on their probabilities. The more experiments we do, the more information we will get about the location of a particle. Some very smart people would most likely say, that the Schrödinger equation collapses with each experiment, meaning that a probability wave will turn into some (trivial) information about something. Whatever that means, it is obvious to us that information pops up in exchange of a certain amount of uncertainty that we are loosing on the way.
We consider time to be just the sum of all the information gathered during experiments.
In particle physics, the path of a particle is somewhat indeterminate. No matter how many experiments we do, we will only end up with an approximate path of the particle. OK. But if we repeat the experiment under the exact same conditions, we might end up with a completely different path, only depending on some probabilistic rules determined by the maths of quantum physics.
But with our understanding of time that does not really bother us any longer. There is no order in time. Time does not flow from 0 to , always in the same direction. It is just the sum of all the information that we can gather. And that does not need to be the same all the time!
Now you know what time is!