There's more to the beginning of the universe than a loud noise

7) Let There Be Atoms!

As time stretched out, so did space. Eventually, the little photons were given more room to move around in, and so they weren’t bumping into electrons wherever they went. This break in the to and fro relationship between photons and electrons is called the decoupling by scientists, which is a bit confusing as it was also the time when one of the most important partnerships in the universe’s history was founded. Finally, a single Electron and a single Proton had the right conditions to come together. This created the original, most simple, most light and most ancient Atom: Hydrogen. It is an element which has been around long before the Earth existed, but is essential to life. When doubled up with Oxygen (an element that arrives in a later chapter of this story), it forms water – H2O. Helium, the second lightest element, was also formed when electrons teamed up with the nuclei that were made of a fused Neutron and Proton pair.

As Atoms began to assemble from the the photon-matter plasma, light found itself free for the first time. No longer trapped in short-sighted interactions with Electrons, it could fulfil its potential and travel along the vast open distances that now existed between atoms. The fog cleared. For the first time, the universe was transparent.

So the photons sped out in wiggly-straight lines at the highest speeds in the universe. It is quite hard to believe, but despite their mind-bending quickness, some of those old, first freed photons which raced through the first unobstructed space are still travelling today. In all those billions of years, there are some which have not collided with even a dust-particle of matter. Stranger still, the chances are that you will have heard them playing their exodus song on a crackly old radio set.

When tuning between stations, you will hear a fizzing sound made up of lots of different frequencies, which is called white noise. This can come from many sources, but a portion of the static that you hear is in fact several billion years old. It has travelled the length of the universe. It is the sound of a select few of those original photons arriving in your living room.

Next: The Inflation