The Big Bang – Seconds Later: Unimaginable Fury
Moments later, fury, chaos and light;
nothing makes sense and nothing is right.
Moments after the Big Bang, all energy had just come into existence was spread evenly across the Universe. Everything was so hot and dense that the typical laws of physics did not apply. When matter is hot on earth, it expands and turns into gasses and fluids with less structure. Everything here was so hot, that not even basic subatomic particles like electrons and protons could form, let alone any atoms. Instead, there was no matter, just crazy weird energy fields. Over time, it then cooled and the energy fields became particles, eventually forming matter. A lot of this period is still not well understood, as it represents extreme conditions that will never exist again in our Universe. It’s truly wild. Let’s dive in, to the very early Universe.
The Universe Right after the Big Bang
Time after the Big Bang is generally divided into very small periods as it cooled, depending on what new types of particles could form. And by very small, we are talking much smaller than a billionth of a second. There are lots of different periods which can be used, but some common ones are:
- The Planc Epoch – 0 to 10−43 seconds after the Big Bang; The least undestood part of the Universes history – there is no good theory to explain what was going on at this point.
- The Grand unification Epoch – 10−43 to 10-36 seconds; : The Universe has cooled to 1032 degrees celsius (thats a 1 with 32 zeros after it). Weird theoretical energy fields exist but not much else.
- Electroweak epoch – 10−36 to 10-12 seconds; The Universe has cooled to 1028 degrees celsius, a point where gravity and electromagnetism can operate seperately. Its similar to the environment at the centre of an atoms nucleus.
- Quark epoch – 10−12 to 10-6 seconds; Some of the most basic building blocks of matter exist such as ‘quarks’, that combine together to form protons and neutrons.
- Hadron epoch – 10−6 to 1 second; Protons and neutrons can now exist, the building blocks of atoms.
- Lepton epoch – 1 second to 10 seconds; Electrons can exist.
- Photon epoch – 10 seconds to 20 minutes; Light, such as photons can exist. After about 3 minutes nuclear fusion begins to produce the most basic elements of the Universe, hydrogen and helium.
It doesn’t matter if you don’t understand all the different periods properly, we don’t really either. The general pattern is that as the Universe cools, physics gets more sensible, and more “normal” types of particles, that we know today, can start to form.
This all sounds a bit weird? Can the Early Universe really have been that different to the center of the Sun? That’s pretty hot, right? The answer is, yes. The center of the earth is hot enough to create rivers of molten iron that would instantly vaporize a human if they touched them. It is about 5,000 degrees. The center of the largest stars is 10 million degrees (that’s 7 zeros). The entire early Universe was hotter than 1032 degrees. There is no standing next to it and taking a picture. It’s something that can only be imagined. Slowly over time, this energy cooled and turned into matter and became the Universe we know, but in its earliest moments, it was absolutely bizarre.
How do we know all this? It’s actually surprisingly easy – we’ll talk about it a bit more in the next blog post. However, the general idea is when something is really hot, it leaves heat behind. If you leave a kettle on the table, the table gets hot and you can feel the heat afterwards, even after the kettle is gone. Similarly, with the early Universe, we can detect the leftover heat (it’s called the Cosmic Microwave background). It isn’t very hot anymore, only about 3 degrees above the coldest temperature possible, but working back from 13.8 billion years, we can work out how hot the Universe was. Then it’s just a matter of creating similar lab conditions trying to work out what particles do at that temperature in those sorts of conditions (that’s what all the “particle colliders” like CERN are for).
Anti-matter: Why is there all this stuff?
Now there is a bit of an extra embarrassing thing we’ve been ignoring. And frankly, we at The Universal Story don’t know how to explain it, without sounding a bit silly.
There is this thing called ‘Anti-matter’. It’s a concept that has entered popular culture to some degree, so people understand it a little bit – an opposite or dark kind of matter. And when you combine it with normal matter, it cancels out into a huge explosion (lots of Sci-fi bombs are made of this stuff).
Now anti-matter absolutely exists. We can make it in labs by running particles into each other. The total amount of it that we’ve ever made in all the labs on earth is probably a few billionths of a gram. And we’ve never really managed to make a proper stable atom worth (just lots of anti-particles). And it occurs naturally out in the Universe in very small quantities, when radioactive things are happening. However, for the most part, it basically doesn’t exist outside labs. There are no anti-matter galaxies, or stars or planets. It really only exists briefly when radioactive things decay and when we make it.
The problem is, this anti-matter stuff definitely existed in the early Universe. As we talked about before, the early Universe was basically the physics of the very small blown up to an enormous scale. So there should have been huge amounts of anti-matter. In fact, according to our current theories, all the maths that explains the particles that would have started existing directly after the Big Bang, predict that there should be equal amounts of matter and anti-matter. And this means they should have been canceled out and no physical matter would exist in the Universe.
This is one of the biggest mysteries left in physics. We have no genuinely good explanations for why this occurs, and why all the anti-matter has disappeared. The fancy physics term for this is ‘baryogenesis’ – the emergence of an asymmetric amount of matter and anti-matter. And the people who study this are frankly as confused as you probably are reading this. For instance, the Wikipedia page on the subject has the rather amusing statement that ‘The universe, as a whole, seems to have a nonzero positive baryon number density – that is, matter exists.’ Thanks Wikipedia.
There are genuinely some physicists who hypothesize there are a big bunch of anti-matter galaxies out there that we just haven’t found yet. There are others who think there is just some flaw in our physics that we haven’t worked out yet. We really don’t know.
Why should we study this? Is any of this important?
Firstly, we just want to know. It’s super weird and super cool.
Secondly, the time after the Big Bang represents a unique moment in the history of the Universe to combine the two main branches of physics.
As a general rule, physicists study either really big things or really small things. For really small things, we have theories like quantum mechanics that describe how small particles interact and the weird teleporty nonsense that the Universe gets up to at very small scales. For really large things we have theories like General and Special Relativity, invented by Einstein to explain the time and space warping weirdness of giant stars and black holes. However, no one has really been able to combine these two theories together to come up with the holy grail of physics, one theory that explains our Universe.
This is fine most of the time. If you are modeling what stars or galaxies do, you use relativity and everything is great. You don’t need to worry about the behavior of the tiny little electrons in the stars for the most part because they are too small to matter. Similarly, if you are studying small things, like electrons in microchips and electronics, you use quantum mechanics and it’s all fine. You don’t need to worry about what the stars are doing, it doesn’t affect what you are studying.
However, the very early Universe is really the only time when these things are combined. You have an enormous density of energy spread across the entire Universe. So you have the things we associate with the physics of the very big. But because everything is so hot, we don’t have traditional matter and atoms. Instead, we have weird particles that are normally very small.
This means the early Universe is the perfect testing ground for theories about how our Universe really operates. The very center of stars can sometimes have similar conditions, but for the most part understanding the few seconds after the Big Bang is our best hope at building wormholes or teleporters or any of the weird physics things we’d love to have, that seem impossible. Let’s wish our scientists the best of luck in cracking this, so they can get us some teleporters and wormholes.
Next up, we are talking about what happens after this initial craziness of the Big Bang and the seconds after. The years after the Big Bang where the Universe begins to cool.
