how would heat death at the end of the universe work if energy cant be destroyed or created?


I learned about the energy only changes form recently and was wondering how heat death in the end of the universe would work because “all energy is lost from the universe”

In: Physics

I think its more like all energy is equally distributed throughout everything, so it is effectively zero energy. Theres no way for energy to be transferred because its all equal

It’s not lost, it’s just so widely dissipated that it’s spread out nearly perfectly evenly throughout an expanse that just gets bigger and bigger (due to eternal inflation from dark energy). Eventually, the uniform temperature of the universe is hovering some infinitesimal amount above absolute zero. Nothing can survive. And since it’s spread uniformly, there’s no way to do “work” – energy cannot be transferred from one part to another. Work requires an energy differential, and there would simply be none anywhere (except for quantum fluctuations, but the larger the quantum “burst” of energy, the shorter the duration of its existence. Here again, anything that could yield “work” won’t exist for long enough to do so.

The heat death of the universe isn’t the loss/destruction of all energy, it’s the death of all differences in heat.
That’s because nearly everything in everyday life requires some kind of temperature difference, either directly or indirectly.

Your car runs because it’s hotter inside its engine than outside. Your computer runs on electricity from the local power plant, which probably works by heating water and using that to power a turbine. And you run on food, which exists thanks to the enormous temperature difference between the Sun and the rest of the universe.

Once everything is the same temperature you can no longer do work and nothing interesting will ever happen again.

The heat death is less about a specific temperature and more about the differences in temperature or energy no longer being meaningful enough to fuel systems that produce energy in the form of “work”, or the transfer of energy from one system to another. I’m not smart enough to go into more detail from there though..

It’s called heat death because all energy is tuned to heat, it’s not lost, it’s spread out everywhere in an infinitely explaining universe, so effectively the energy density is so small that it might as well be zero and even then it’s so spread out that it’s impossible to use any of it

Energy naturally spreads out via thermodynamics, but at the same time the universe is becoming larger and larger via expansion, and as a result the finite amount of available energy is being spread across a larger and larger amount of space.

Further, due to the 2nd Law of Thermodynamics, the ability of energy to do work is directly tied to the imbalance of energy between two different sides of a given reaction. The less imbalance there is, the less work can actually be done, and once all the energy of the universe is spread evenly across spacetime, it will be thermodynamically impossible for anything to happen, regardless of how much actual energy there is.

My theory is that all the entropy is focused at the centre of a supermassive black hole, entropy is either achieved or as little as a single atom does not fit in the system causing another Big Bang.

Energy can’t be created or destroyed (except for nuclear stuff, but let’s not go there). However, for energy to be useful, we need to be able to move it from one place to another. *And* every time we do this, it needs to go from being clustered together to being spread out. It’s this spreading out that is what happens when we ‘use’ energy.

The idea of the heat death of the universe is that all the energy becomes equally spread out. That means there is no way for any of it to be used because we can’t do any more spreading. So, all *useful* energy has gone.

I should add, you *can* clump energy together. For example, charging a battery. But doing this required spreading out more energy somewhere else, e.g. the power plant that gives your home electricity.