How did we come to be here, right now, sitting comfortably in our bit of the Universe surrounded by everything we see? For the time being, and for the sake of argument (or rather lack of argument) let's forget about deities that just created everything and stick to the scientific story. I guess, for me at least, it's one of the more amazing and awe inspiring things about being human - we're just an ape-like entity, existing on a rocky ball circling about an un-pretentious star in an unremarkable part of space and time and yet by intellectual and logical effort alone we have developed solid ideas that take us back nearly 14 Billion years (14 followed by 9 zeros) to within \\(10^{-40}\\) seconds or so (1 divided by 1 followed by 40 zeros) of the start of our Universe. OK, there are still plenty of questions, discussion and argument but our current theories really do describe and predict an awful lot of measurements we have made. So let's start at the begining and follow it through.


In the beginning there was the Big Bang where everything (including time itself - probably) started. Think on that - there wasn't anything 'before' this. Not 'empty space' (space didn't exist) nor time - there really was NOTHING. Why do we think this is the case? well it's based on simple observation. When we look out into the Universe we can see that everything (well everything that isn't pretty local) is flying apart from everything else - the Universe is expanding. For a time in the 20th century there were a couple of good candidate hypothesis to explain this strange fact. The first was that matter was being continuously created slowly but everywhere by space itself - not much but the shear vastness of the Universe volume meant that this process produced a steady expansion. The second was the Big Bang. This came from the idea that if everything is expanding away from everything else, then if you run time backward it must mean that at some time in the past everything will come together into a single, infinitesimally small 'point' from which (if we run time forward again) everything 'explodes' from. Both hypotheses 'worked' but made subtly different predictions about what we should 'see' by looking deep into space. Both theories thought some kind of microwave radiation might be observed but only the BB theory predicted that we should see very cold Black Body radiation. In 1964 a number of observations were made but the most famous ones were by a couple of Bell Telephone Laboratory employees, Arno Penzias and Robert Woodrow Wilson. They were carrying out experiments to do with satellite communications and radio astronomy but couldn't get rid of an annoying background signal. It was soon realised that this wan't just a rubbish receiver but was in fact a real signal from space. Further work showed that it did, in-fact, follow the spectral 'shape' of black body radiation at a temperature of around 3 or 4 degrees Kelvin (above absolute zero). So, Steady State was out, and Big Bang was in! Penzias and Wilson duly got their Nobel prize.

So, now let's look at what we think happened - from time=0 when the 'Bang' happened.

But, but … You might ask some questions around about now (13.8ish billion years after the start of time):

1. How do we know; what 'proof' do we have that something as bizarre as 'inflation' took place?
2. Why was more matter synthesised than anti-matter?
3. As nuclei formed, only H, He and Li were synthesised (to all intents and purposes at least). Where did all the other stuff (arguably 98 naturally occuring elements) come from?