The history of life is written in terms of negative entropy — James Gleick
To answer the above question let’s assume we are in a hypothetical Universe similar to our real Universe (almost all physical laws apply)
Imagine we are in space of a hypothetical Universe, wearing a space suit and holding small block of wood. We are given the task to move the block in space. We know we need to apply force to move something in the three dimensions and forces are the way that energy is transferred from one object to another when they interact. Now you have burned some of your energy and created a force to move the block and as a result the block has achieved some acceleration
We know that Entropy is the measure of the disorder of a system. In simple words it is a measure of the amount of energy which is unavailable to do work. So energy transferred to the wooden block results in the loss of some usable energy. The second law of thermodynamics states that every energy transfer increases the entropy of the universe. Is it the positive entropy change in our Universe that accelerated the block and thus resulted in its movement?
Let’s assume it’s the positive entropy change that accelerates bodies in our Universe. Now the wooden block disappeared and we were placed inside a fast rocket. We know that the thrust in rocket is generated through the reaction of accelerating a mass of gas. To accelerate the gas we have to expend energy and energy is generated as heat by the combustion of some fuel. The combustion creates positive entropy and as we assumed earlier that a positive entropy change will result in acceleration we see our rocket accelerating with an acceleration ‘a’. The rocket in our Universe is so advanced that it can expend energy equivalent to our sun and it can travel almost nearer to the speed of light.
Now we escaped from that Universe in our rocket so they placed a fireball like our sun in the middle of our hypothetical Universe. The prodigious amount of energy in the Sun comes from the nuclear fusion process that takes place in the central region of the Sun which converts hydrogen into helium plus energy. One thousand grams of hydrogen produces 993 grams of helium with 7 grams of mass being converted into energy via E=mc2. This also creates a positive entropy change and as we assumed it should result in acceleration of the sun. Unlike rocket which accelerates and speeds up by creating thrust on opposite side, the sun radiates uniformly in all directions. So how can the sun move or accelerate despite being a energy ball. As it was not possible to accelerate into all directions at once, the Sun maybe pulling the space around it with the same acceleration (acceleration due to gravity…hmm) . Being in the vicinty of the Sun or moving inside the rocket with same acceleration should feel the same.
So we can assume that if a positive entropy change takes place in our hypothetical Universe, it will create a movement in any dimension and since time being a dimension, any positive entropy change in Universe should create a movement in time.
Since it’s established that a movement in time is possible via the entropy change in our hypothetical Universe we could be wondering that while we were in the rocket earlier we know we moved through three spatial dimensions but is it possible to move in time instead?
Before answering the above question we need to understand relative speeds. When the object moves with the speed of light it will have only the spatial speed and no temporal speed and a stable object without any movement will have only temporal movement and no spatial movement . Assuming positive entropy change always results in movement, either in spatial or temporal it will be relative. In simple terms, for the same postitve entropy change if the object is stable it should be moving in temporal dimension and if the object is moving it should be moving in the spatial dimension . This creates further interesting questions
Why does time have to run slow for an object in a fast moving rocket with acceleration or nearer the heavy bodies like sun with acceleration due to sun’s gravity . Does it have any relationship with the total positive entropy change in the Universe? Does overall entropy change have to remain same for every object in the Universe whether it is stable or moving?
Since the issue is related to relativity, let’s proceed with a thought experiment by placing two people in our hypothetical Universe immediately after the Big Bang. Let’s say our Universe adds up 2 units of positive entropy for every second, beginning from the big bang. In simple terms, for every 2 units of positive entropy change, any stable object in the Universe has to move one second in temporal dimension. We will be placing our two people separating them by a large distance and one of them will be given a rocket which will take him one second to reach the other person who is stable. Both of them have special equipment which can record every entropy change in the Universe and both of them have very precise clocks for recording time. Now the big bang happened and four seconds passed, the entropy change of the Universe is recorded as 8 units and the rocket person started his rocket and began moving towards the other stable person. The rocket combustion added 2 more additional units to the entropy change. At the end of 5th second the rocket person reached the other stable person and the rocket person’s equipment was showing 12 units of entropy change (2 from the rocket combustion and 2 from the Universe) and his clock showing 5 seconds. Both checked the clocks and the stable person is one second ahead of him with his clock showing 6 seconds. The stable person also recorded the extra 2 units of positive entropy change created by the rocket combustion and his equipment was also showing 12 units of entropy change. Since the positive entropy change should result in a movement either in spatial or temporal dimensions and stable person being stable in spatial dimensions should move in temporal dimension to conserve the entropy change. The 2 units of entropy resulted in 1 second movement in temporal dimension for the stable person. This made rocket person feel, like his time dilated to conserve the total entropy change but what happened instead is that the stable person moved in time ahead of him to conserve his total entropy change.
We can assume the stable person without any influence of heavy masses or any accelerations moved faster in temporal dimension relative to rocket person
The above example may or may not hold true in the real Universe but we know for sure a relationship exists between entropy and time and the positive entropy change in the Universe should either result movement in spatial dimension or temporal dimension or both