We have two scientific theories... The Law of the Conservation of Energy, which states that the amount of net energy in a closed system remains constant (nothing spontaneously creates or disappears) and the Law of the Conservation of Mass, which states the same but for mass. Essentially, both state that in a closed system, things do not appear or disappear. The amount of mass and energy in the universe is the same as it was at the dawn of man and will be the same at its demise, granted that energy and mass will take on different forms, but the quantity of energy and mass remain constant. I would add that mass can become energy (such as gasoline combustion) and energy can become mass (such as weather). They are interchangeable if the correct conditions are present--in the case of weather that condition would be sunlight; in the case of gasoline combustion that would be fuel, oxygen, and ignition.
When you die your body decomposes and the electrical impulses throughout your body break down into less complex forms of those entities. Your body gives off heat until it is the same temperature as its surroundings; your body decays until it is comparable to its surroundings. The prior process can only take a little while. The latter could take centuries or millenia to complete fully. Eventually even your bones disintegrate. Eventually you become indistinguishable from your surroundings (the earth you were buried in for instance).
Mineral enriched soil grows plants or else remains part of the earth (even if only impactful based on the infinitesimally minute gravity your disintegrated remains provide). The universe moves on. We do too. Just as a different type of existence. Nothing leaves or enters the universe ever. Mass and energy are funneled through our bodies throughout life and those things sustain us as we are. We are a vessel for the transference of energy to mass and of mass to energy. These entities impact us, their vessel. Energy and mass grow us in our sex cell form from preexisting systems in our parents' bodies (which were also nourished by energy and mass), at conception energy and mass add more to build a human being. We eat food and gain energy and mass throughout our lives to grow and to change. Even as we age, our cells divide and are replaced periodically using the energy derived from food which were derived from bundles of mass called seeds or embryos, nourished by the sun (energy). We are part of a cycle of transference between energy and mass.
One may ask, when did the mass-energy cycle start. I believe that it is cyclical, as nothing ever enters or leaves the universe, just transfers from mass to energy and back again. The universe has no beginning or end. The Big Bang is just a violent movement from energy to mass. The accelerated growth of the universe is an illusion based on the creation of new "space" from energy along the skeletal structure of the universe. Blue shift is the transfer of "space" from mass into energy en masse. Red shift is the opposite.
If there is no beginning or end, then there is no creator. I have shown a way in which the universe does not need a creator. I have shown a way in which the universe does not need anything "beyond" the universe to exist, continue, or change. It is a self-sustaining unit that has no beginning or end and no heaven or hell. "After we die" is comparable to "before we were born" in experience for us in terms of how we should view it.
What is the purpose of the universe then? There is no point of the universe in terms of what the universe would "think" the point of existence is. There can't be. Why do we exist? To others we exist for companionship, love, as a writer, parent, teacher, employee, etc.; but, we don't exist for any reason for ourselves. Our "purpose" is only in relation to others. We do not have a purpose in relation to ourselves, the same as a computer doesn't have a "purpose" except in relation to humans or the ocean doesn't have a "purpose" except in relation to that which lives in it. The same is true for the universe. The "purpose" of the universe is dependent on the needs of those entities residing within it which have needs that it can fulfill. As the universe is everything and a closed system, the purpose of the universe to us and to everything in the universe is "everything". Everything is the purpose of the universe. Remember that nothing ever enters or leaves the universe. It is self-sustaining and self-providing.
The only question that I have is whether there is a finite or infinite number of possible forms for mass and energy and for interactions between mass and energy. If there are a finite number of forms of mass and energy and a finite number of ways that they can interact, then the universe never changes permanently. This is the theory I am leading to. Like a pencil sketch, what is formed can be erased, no matter how long it is there or how grand or complex it is. This theory suggests that the universe does not have a "net evolution", in that eventually any changes change back to their previous states. This also means that there can be no "greater meaning" or "purpose" for the universe insofar as permanent growth. That which is built will eventually crumble. Judging by examples on the human scale, I tend to believe this is the most likely scenario.
The second scenario states that there are finite number of forms of mass and energy but that there is an infinite number of ways they can react. This scenario is illogical to me as it breaks with my perception that the universe as we know it has constant laws. Science has many such "constants" such as E=mc2 or C2H4 + 3 O2 + Energy -> 2 CO2 + 2 H20 + ENERGY. These constants and a million others are examples of evidence for universal laws-- i.e. that the universe is governed by a set of rules (granted it would be a fairly large list). I do not believe that the force of gravity in Area A would ever be different than in Area B if all conditions are identical. Therefore, this scenario does not seem plausible. If there are a finite number of forms for mass and energy and an infinite number of ways they can react, then there is no method to the madness so to speak--the entire universe and everything in it would be completely random. Observational evidence suggests otherwise-- that there is a set quantity of rules that are constant.
The third scenario states that there are an infinite number of forms of mass and energy and a finite number of ways it can interact with each other. This scenario is interesting in that it cannot be proven or disproven. There is evidence, however, that it is not the scenario that the universe runs by. For this proof, lets look at mass, which is generally visible or at least we can comprehend its existence. Energy is too illusive to us currently; we do not yet know its true nature. Note this, as it is important in that without all the information we cannot prove this scenario right or wrong. So, in regards to mass, we have the periodic table as a good starting point. Of course, the universe is actually made of strings of vibrating energy, but we are sticking only to the levels which we can physically see and will then make generalized educated guesses about that which we cannot yet comprehend.
The periodic table has grown over time to include an increasing number of elements, however the higher we get on the table the more unstable these elements are. Indeed as we get to the 100's we see elements which cannot exist except for brief moments and in high-pressure situations. The universe tends towards low-pressure--entropy--when existing as mass. It is safe to say that there are far fewer areas of high pressure than low pressure in the universe with even a cursory glance of the night sky. The centers of stars and laboratories can create high pressures, but for the most part they don't exist. Therefore, the higher end periodic atoms also cannot exist except for in increasingly less likely higher pressure situations. (The higher the pressure you need to maintain the atom, the less likely it exists.) Therefore we can say that in all likelihood, the interactions which mass and energy can take must tend towards finite even if it cannot be proven to make it to that point. There comes a point where the likelihood of additional kinds of interactions becomes nearly infinitesimally unlikely. Therefore, I believe this scenario is wrong.
The final scenario is one in which there are an infinite number of forms of mass and energy and an infinite number of ways in which they can interact. I believe this scenario to be impossible based on the reasons why scenarios 2 and 3 are impossible. There cannot be an infinite forms of mass and energy because there are laws which govern the universe and there cannot be an infinite number of interactions between mass and energy because there comes a point when the quantity of types of interactions tends towards the finite and the likelihood of there not being any new kinds of interactions nears infinity.
With a finite number of forms mass and energy can take and a finite number of ways they can interact, eventually every possible combination will happen. This is a reincarnation of a sense isn't it? Perhaps I should think more on this next time.