What does modern physics actually tell us about why we are here?
Well, an awful lot actually. As a physicist I am proud of the achievements of my colleagues who work in astrophysics, particle physics and related disciplines, as they enable us to understand more and more of what is going on in pictures like the one above, or at the very most micro of microscopic frontiers of our knowledge. The suite of quantum field theories and Einstein's theories of relativity (Einstein actually contributed one of the key early findings to quantum theory as well) enable us to write down the fundamental theories of science in a very few equations and explain the nature of all matter and forces in terms of a single set of 61 elementary particles in the Standard Model. Essentially, all physical phenomena and other concepts in biology, chemistry, geology, medicine etc can ultimately be derived from these equations and particles to a very high degree of accuracy - except under very extreme conditions. We understand a great deal about human beings and the world around us.
Extreme conditions include black holes, very high energy interactions between elementary particles and the state of the Universe its very early stages of development according to the most commonly accepted theory of its origin - the Big Bang. That doesn't mean that everything else is understood under less extreme conditions, but we pretty much have a handle on them and know what it is that we don't know in most cases.
To get to this stage is an amazing achievement of human minds. Some would say that God has allowed us this knowledge and made us in a way that we can figure it out, or even guided us to some extent; many others, though, see this just as an incredible outcome of the human brain as it evolved from the Big Bang. It is fair to say that the odds are stacked against the latter interpretation, for many reasons, but today I want mainly to celebrate what we have been able to achieve by way of fundamental knowledge and the understanding of what we have discovered. Surely we can all marvel at the Crab Nebula shown below and the fantastic detail in which we can observe something that lies about 6,500 light years distant from the Earth (38,211,060,000,000,000 miles).
So what about the extreme conditions? Therein lies quite a big can of worms, which should not be opened today. More important at the moment than what we don't know is what we do actually know about what we don't know. In this case we are talking about unknown unknowns, because we do not yet have a successful handle on how to investigate the missing knowledge, so we don't really quite know what we are looking for. The amazing fact that we do know though, is that we have no idea what 95% of the Universe comprises. That is a massive whole in our knowledge, but it is an incredible fact that we can be so sure about how much we don't know, given that we have never detected or experienced it, or come up with a theory that looks as if it is likely to be successful. The dark matter and dark energy that keep on turning up in the news these days are essentially still just words and until, if ever, things progress beyond that, we remain a very long way from a scientific theory of everything that explains our existence.
So let's celebrate this amazing Universe and all the wonderous things that we know about it, and enjoy the fabulous pictures from the Hubble telescope that we can find on the web!