So… you're saying your laptop is super cool? Because the heat death of the universe is when thermodynamic energy is equally distributed everywhere, which, given the large space of the universe, means really cold.
So… you're saying your laptop is super cool? Because the heat death of the universe is when thermodynamic energy is equally distributed everywhere, which, given the large space of the universe, means really cold.
Here's a fun game. Have you ever played Follow the Energy? For example, depressing keys on your keyboard takes energy. Where does that energy come from? Well, the work performed by your fingers of course! But where does that energy come from? Well, the muscles in your fingers, of course! But where does that come from? Well, your food! But what about that? Well, your food's food! That? Eventually plants. That? The sun! That? Nuclear fusion. That? Gravitational potential! That? Etc...
But here's the funny thing. In this image, it kind of seems like energy gets "used up". The sun provides energy to the earth via solar radiation; the plants consume this energy; animals eat the plants, obtaining their energy; etc. However, energy is conserved. What gives?
Better yet, if the earth were not radiating just as much energy as it received, it should be heating up. However, the earth-atmosphere system is mostly constant temperature! This implies that the total energy flux is zero. If X Watts (Energy/Time) is coming in, then the earth actually radiates out X Watts as well.
So... if the total energy flux is zero, then how does your keyboard key actually get pressed? What gives?
The key is entropy. X Watts of solar radiation impinge upon the earth, but these photons are "hotter" (i.e. higher frequency) on average than those that radiate out. The balance is in numbers. You need more cooler photons to balance the energy of the hotter ones. E=hf; energy (E) is proportional (constant h) to frequency (f), after all.
This means that while energy is conserved, the flow of that energy increases the entropy of the system. In a very real sense, typing on your keyboard happens because of the waste heat generated in the process.
All driving us closer to Heat Death...
It's also interesting to play the "Follow the Energy" game to it's logical conclusion, namely that nearly all of the energy in the Universe (including that which you expend typing on your keyboard) originates from the gravitational potential created in the Big Bang (whatever that is, by the way). This begs the question; how was the entropy of the early Universe to low, that it could increase by such an enormous amount, to produce intelligent beings such as ourselves, typing things on a keyboard while we should be working?
It's really one of the most fundamental questions in cosmology, and one of the (many) reasons why I love physics.
Minor pedantry on top of pedantry. The gravitational potential energy of a collapsing protostar gets you past the activation barrier for nuclear fusion, but isn't itself the source of energy beyond that.
Think of it like lighting campfire using friction. The friction heats up the kindling, but that investment allows you to access the potential chemical energy of the wood. The gravitational potential energy is converted into heat, and that investment allows you to access the potential nuclear energy of the unfused hydrogen.
Nice analogy, btw.