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All of the energy around you, from the light bouncing into your eyes to the heat coming out of your toaster, comes from an unbroken chain of events going back to the Big Bang.

In fact, all the energy that will ever exist was created in that moment. This is because energy only ever moves from one place to another, it never truly disappears. This is the law of the ‘conservation of energy’.

Let’s take a closer look at the light coming out of your screen, and where it comes from.

If you took your screen apart you’d see a backlight, which releases light as electricity (electrons) flows through it.

An LED backlight

Whether you’re using a phone, laptop, or desktop, it originally got those electrons from a wall outlet. If you follow your outlet’s wires back far enough, along power lines and high voltage lines, you’ll probably end up at a hydroelectric dam (but it could be a windfarm, a solar farm, or a coal or nuclear plant, depending on where you live).All of a power lines in a city will generally link up and go to the same source.

Once you reach the hydroelectric dam, you’ll find it’s busy pushing electrons into the power lines through turbines. Each one contains an electromagnet set up in reverse such that when they turn, they force electrons to move down the line.

At the Hoover Dam water flows underneath this hall, which turns these turbines.

Hydroelectric dams tap into the water cycle to get their energy. Dams are built on rivers as reservoirs, and they let some water flow through. When this water flows downhill, it pushes the dam’s turbines.

If we follow the river back to its source, we’d find that it ultimately comes from rain.

Rain in the Rocky Mountains, upstream of the Colarado River and the Hoover Dam

Rain was created because water evaporated from lakes and oceans and was pulled into the sky, a natural consequence of the sun’s radiation and heat.

Water from a lake evaporating from the Sun’s heat

This radiation travelled through space, and originated on the sun’s surface, 150 million km away. The sun is a ball of super heated plasma, and all of this furious energy comes from nuclear fusion deep within its core.

The incredible heat of the sun evaporates water on Earth, 150 million km away

Nuclear fusion releases the latent energy that is within hydrogen atoms.

This energy is a part of all atoms that are lighter than iron, and it comes from their creation during the Big Bang.

The Big Bang, the moment that created the raw material for the entire universe, including all of its energy

It is interesting to think that if the turbines at the dam stop turning, then your screen will turn off.

If the rain stops falling, eventually the turbines stop.

If hydrogen runs out, then it never rains again.

Because all the energy in the universe was created during the Big Bang, and it is moving from place to place, it won’t ever run out.

However, it might reach equilibrium, and that will mean the end of all chemistry, life, civilisation, and technology.

To explain how this happens, we can imagine the energy of the universe as like the colours in this trippy video.

The Colors of Feelings from Thomas Blanchard.

Imagine that each colour paint is a different type of energy (like heat, light, electricity, etc.)

Darker coloured paints represents areas represent a higher density of energy.

Lighter coloured paints are areas that have a low density of energy, like outer space.

When stars push all of their heat and light out into space, it’s like a darker colour paint smearing over a lighter coloured paint. Or on a smaller scale, when you light a fire you are pushing heat and light from the high energy wood to the low energy air, which heats it up.

Everything comes from this type of movement of energy. All light, heat, movement, and electricity are possible because of energy flowing from a higher density spot to a low density spot.

The problem is that eventually, the painting will become a uniform grey blob.

There will be a point where the paint is fully mixed up, and there is nowhere that is higher density than anywhere else.

No further movement of energy becomes possible. No moves are left, like cars stuck in the ultimate form of gridlock.

This is called the heat death of the universe. It is where every part of the universe, including everything that used to be galaxies, stars, planets, and computer screens, cools to just above absolute zero.

In the meantime, there could be millions of different forms of civilisations, consciousness, and technology. But in the end, everything in the universe will grind to a standstill.

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Ben McCarthy

Ben McCarthy

Ben is the Founder of Discover Earth and the author of the Big Ideas Network.