This is not a question about the meaning of life. That is whatever you decide to make it. Nor is this a purely metaphysical question, although it covers areas that have traditionally been the domain of philosophers. When scientists talk about reality they talk about tangible things – atoms and molecules, particles and radiation. But of course this is only the reality. Whether directly, through our senses, or indirectly, through our machines, we construct a picture of reality that resides not out in the stars and galaxies but within our heads. The old solipsistic chestnut about the world possibly being a figment of our imagination cannot ever be dismissed out of hand. Can the idea that the world, including ourselves, is a figment of someone else’s imagination. That said, the fact that we have managed to formulate physical laws which correspond so exactly with what we observe suggests that while ‘reality’ may be what we perceive, we are perceiving something that is very concrete indeed.
For example we don’t know about the ultimate nature of the Universe. For a start, what is its ultimate cause? Twenty years ago cosmologists stated flatly that the answer was simply ‘the Big Bang’ and left it at that, but now scientists are starting to realize that this is not good enough. What was the bang exactly? Why did it bang and what happened before? Now we think of the Universe as a vast, 92 billion light year diameter sphere of expanding space–time driven by a mysterious
dark force field that we do not understand and populated mostly by a ghostly form of matter that we cannot see and cannot feel. Is this any less strange than those old folk cosmologies (The Earth sitting on the back of a turtle. The Earth as a disc floating in an infinite sea. The sky as a dome
through which the lights of heaven are visible as the pinpricks of brilliance we call the stars…)? And is this the whole picture? Or is “our” Universe simply a tiny mote on the back of a far vaster, far grander, appendage?
A popular solution to the initial cause problem, and indeed all the questions we have about the nature of the Universe, is of course God. Across most of the world and certainly for a vast majority of people the existence of some sort of deity forms a perfectly acceptable bookend to all chains of inquiry about themselves and the world in which they live. It is certainly the case too that even in our so-called secular age many scientists continue to believe in God. Most scientists do not, any more, consider God to be a rational solution to the question of “How did the Universe come into existence”?But the Big Bang model is incomplete and there are many gaps. One important gap, albeit not with the model itself, is the general conceptual misunderstanding of the Bang as a gigantic explosion which threw vast quantities of shrapnel blasting into space, which later became the stars and galaxies. It is not entirely clear what happened, to say the least, but it is clear that the gigantic expansion of the universe that took place in the first millisecond after the Big Bang was an expansion of space–time itself, carrying the matter and energy embedded within it. It is better perhaps to imagine the Big Bang not as an explosion but more as the blowing up of a balloon. But there are other, more serious problems, as even the Bang’s most enthusiastic defenders will concede. For example, as we peer further away from the Earth we see galaxies as they were long ago. The light from very furthest objects that we can see left on its journey to Earth very shortly after the Bang, which is thought to have taken place 13.7 billion years ago. These very distant, very early galaxies are only a few hundred million years old, as we observe them, and should therefore be packed with very young, immature stars (our star, the Sun, is more than 4.6 billion years old). And yet many appear not to be: some of these very young, very distant galaxies look like mature galaxies full of ‘old’ stars. Then there is the fact that some of the stars we observe seem to be “older” than the Universe itself. What happened ‘before’ the Big Bang used to be seen as a pointless question, as it was considered that both space and time were created during the Big Bang; to talk of a “before”, therefore, is meaningless. But this view has been challenged, most notably by the Cambridge theoreticians.”Our” universe “floats” on a three-dimensional “brane” which moves through higher-dimensional space. The Big Bang, for which we have so much evidence today, was an event caused when “our” brane, after a period of contraction, collided with another, generating a great deal of matter and radiation.
Insights into the very early Universe will also come from particle accelerators. As well as searching for dark matter particles, the collisions that will take place in the Large Hadron Collider in CERN will generate energies on a level similar to those seen in the Big Bang. The grand swoop of lights we see on a clear night sky is impressive enough; knowing that all those twinkling lights are not only a mere tiny fraction of all the stars out there but in addition that all the stars together possibly form just a small part of what is, is humbling beyond belief. The question of reality and what it is has been asked by philosophers and theologians for centuries. Now the baton has passed to science. It remains to be seen whether experiment and observation will end up enlightening us any more than the elegant reasoning of old……..