You’re going to have to excuse my pathetically under-educated simplification of this mind blowing issue but I do find it fascinating, especially as I’ve recently watched a few related TV programmes. I even went as far as reading the text of a speech given by Professor Stephen Hawking in 1988. He’s been trying to put the finishing touches to his earlier revelations for the last 30 years or so with little success it seems. The man’s just not up to the task! ;)
If Hawking is having difficulties then what hope have I got! To say most of this goes over my head is be a massive understatement but let’s meander through what is known and what is not.
I think I understand why the “steady state” theories of old don’t work. This is the idea that the universe has always been its current shape/size and will be so forever more. There are (at least) three things that squash that idea;
- Entropy and the Second Law of Thermodynamics. Don’t try reading about this! I ended up with the “simple introduction” and still got a headache. Essentially, this suggests that if the universe had been the way it is for donkey’s years then everything would be the same temperature. Same as leaving a glass of iced water in a warm room for a long time, eventually the temperatures even out.
- Gravity. As pondered by Newton and cheated around by Einstein, if we had a steady state then clusters of stars should all fall toward a ‘centre of gravity’ and bump into each other. Assuming Newton’s law of universal gravitation is correct of course. As it is, the gravity that would make the stars do this ‘big executive toy ball bumping in the sky thing’ is offset by the velocity with which they are moving away from the centre (and have been theoretically since the big bang).
- Hubble’s Law. This tells us that distant galaxies are running away from us at a velocity proportional to their distance from us. The velocity of these objects was worked out from their redshifts. An observed redshift due to the Doppler effect occurs whenever a light source moves away from the observer.
Now, what I’m calling ‘steady state’ shouldn’t be confused with the Steady State Theory of the universe. This was more of a ‘Steady State – now with added expansion!’ model that allowed for an expanding universe (by then indisputable) that back-filled itself by generating new matter. This universe had no beginning nor end and all kinds of matter or galaxies could appear at any position in the universe. This feels much more like a Star Trek kind of universe to me. Anyway, the idea still has a few champions but is largely if not completely trashed by a bunch of observable things like cosmic microwave background radiation, quasars and radio galaxies only being found a long long way away and so on. What this theory did most effectively was to drive research that would eventually get everyone thinking that the big bang was the way to go!
What we think we know.
The story goes that 13.73 ± 0.12 billion years ago there was this very small, very hot, very dense and exceedingly weird blob. We have a fairly good understanding of what happened from 10-43 seconds after the BANG until today and on into the future (assuming nobody moves the goalposts).
So where did all the matter come from if this blob was so tiny? Apparently, matter can be created from energy and this embryonic universe might have borrowed massive amounts of energy from gravity which it then turned into matter. Apparently we’ll need to pay back this “gravity debt” when the universe comes to an end! There was a funky thing that happened very early on to determine that our universe was made of matter as opposed to antimatter, but otherwise everything from this point on seems to have followed the rules our best brains have written over the years.
What we don’t know.
What remains a mystery to Mr. Hawking and everyone else is what happened between BANG and 10-43 seconds afterwards. Amazingly, this incredibly small moment in time has a name. It’s called the Planck Epoch. Technically speaking, it is thought that during this period all the ‘stuff’ that made up the blob (fundamental forces, gravity, bosons, it’s all Chinese to me) got excited and kicked off the extremely rapid expansion of the universe. However, it appears that none of our current rules apply within the Planck Epoch and so until we have some new ones, we really have very little beyond a lot of guesswork.
This passage from Wiki explains why this is still a mystery far better than I can:
As there presently exists no widely accepted framework for how to combine quantum mechanics with relativistic gravity, science is not currently able to make predictions about events occurring over intervals shorter than the Planck time or distances shorter than one Planck length, the distance light travels in one Planck time—about 1.616 × 10-35 meters. Without an understanding of quantum gravity, a theory unifying quantum mechanics and relativistic gravity, the physics of the Planck epoch are unclear, and the exact manner in which the fundamental forces were unified, and how they came to be separate entities, is still poorly understood. Three of the four forces have been successfully integrated in a common framework, but gravity remains problematic. If quantum effects are ignored, the universe starts from a singularity with an infinite density. This conclusion could change when quantum gravity is taken into account. String theory and Loop quantum gravity are leading candidates for a theory of unification, which have yielded meaningful insights already, but work in Noncommutative geometry and other fields also holds promise for our understanding of the very beginning.
It is good to know people are working on it but when you have a thing as uncertain as this I’m wondering if we’ll ever really understand what happened? To use a simple analogy our knowledge of the beginnings of the universe has reached a point where we know everything about the bullet that is flying across the room. We know what its trajectory will be, where it will hit the wall, how far it will bury itself into the wall, what the bullet is made of, how hot it is, how fast it’s going, its density, what it is made of, etc. What we don’t know is who or what pulled the trigger or how the trigger moved the bullet! When you come to think of it, that’s quite a lot of important information missing, even if it is all squeezed into a trillionth of a second or so!
Personally, I’d like them to discover that time actually extends backwards beyond the Big Bang. To discover that our universe has been expanding and collapsing for goodness knows how long. There might have already been an unknown number of repetitions of the same – BANG, GROW, SLOW, COLLAPSE – sequence, each one creating a totally unique universe from the same raw materials. I prefer to think of the Big Bang therefore as not so much the first act of a single expansion but as the last act of one of many collapses. Try and get your head around that!
It’s interesting to imagine that each time the bang occurs the material that makes up the universe scatters itself in very different ways. Sometimes creating life on planets, sometimes not. A bit like dropping the same 50,000 marbles on the floor repeatedly and life will only be created if the single red marble touches the single green one. The actual odds may be better or worse than this, I have absolutely no idea!
Might our feelings of having been in a previous life and all that associated voodoo not be related to earlier lives on this planet in this universe but to lives on another planet in an earlier version of the universe? It is unlikely that our body chemicals would be able to retain such memories after being squished and exploded again in such a manner but hey, who knows? In this arena of scientific investigation it seems that almost anything is possible. The vast majority of our universe is missing anyway, only 4% of what we think should be there is actually visible, the rest is hypothetical dark matter or dark energy. Even the atoms we’re made up of have got massive gaping holes in them. Did you know that if the nucleus (the only bit you might bounce off if you bumped into it) of one of your atoms was the size of a marble then there would be around 3 km of wide open nothingness all the way around it before you came across any of the electrons wobbling around the outside? That’s an awful lot of nothing!
So, on that basis I think I am safe to speculate for now, until someone finally cracks the secret of those very first moments at least.
Where does God come into it all? Well, if there is such a thing we might be doing it a great injustice by limiting its powers to just the one spark of ignition. Perhaps our ever expanding and collapsing universe is just one of God ‘s little experiments? Maybe God is playing with its own somewhat larger version of the CERN particle accelerator exploding and shrinking all this matter until it gets a universe it likes?
I think it’s important to have a sense of your own unimportance in the great scheme of things.