Heat Death of the Universe

Ahhhhh apocalypse theories, you've got to love them. There is nothing quite like reading about how the human race will inevitably meet its demise. There are the fan favourites: nuclear holocaust, asteroid collisions, alien invasion; but there are some weirder (and scarier) ones out there. I for one am a big supporter of universal thermal equilibrium - or the catchier version "THE HEAT DEATH OF THE UNIVERSE".

The Apocalypse ticks ever closer.

On the face of it the theory isn't a complicated one, and in reality seems an obvious end point for the universe. To explain it we'll use an analogy of thermodynamics that everyone has probably experienced, making a bath. When you draw a bath, you use a combination of the hot tap and the cold tap in order to find the temperature you want. Thermodynamics is responsible for a lovely hot bath, without it you'd have pockets of scalding hot and freezing cold water at random points through the bath which would achieve the opposite effect of a "relaxing bath".

We can thank Thermodynamics
 for enjoyable baths.

Thermodynamics dictates that when two bodies of differing temperatures come into contact with each other they will exchange energy (energy and temperature are basically the same thing), until they are the same temperature. This principle helps us a lot in everyday life - apart from an evening bath - allows the boiling of water, air conditioning works, and we can actually cook food. It is a wonderful thing, that is until you consider it on the grandest scale.

By and large, the universe is pretty much in thermal equilibrium already - if you look at it as a grand picture - the Cosmic Microwave Background showcases this very well. However on the smaller scale, it crucially isn't, it's because of this that stars can burn, planets can form, and life can flourish. So what happens when everything - even on those smaller scales - hits equilibrium? Well, the short story is everything stops. If all particles exist at the same temperature, the same energy level, then they can't exchange energy. If they can't exchange energy basic physical processes can't happen. If basic physics can't happen then chemistry doesn't happen, which means biology doesn't happen, and life ceases to exist. Welcome to the end of existence, all because of thermodynamics.

The Cosmic Microwave Background (CMB) is a map of the entire universe at the earliest possible point we can see in time.

So that was cheery, we went from a nice warm relaxing bath to the complete end of all life. In order to end on a more positive note, we'll acknowledge that as an apocalypse theory - despite its logical conclusion - it isn't exactly at the top of the list to avoid. Humanity is far more likely to be eradicated by itself, long before the trillions upon trillions of years that complete thermal equilibrium would require to take hold.

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