Did you know we can only see about 4% of the universe? If the universe was a wedding cake, all we can see is the icing and no underlying confectionery? And, no, this is not some "how far can we see into space?" sort of question.
Let me explain. It started as a very simple experiment: the mass of the universe was calculated theoretically and then measured by the best methods available. It was discovered that the universe is way, way more heavy than all the material in it. Which is logically impossible.
Initially thought to be an error, theories of how this could be so were coupled with observations and we got the answer. 96% or so of the universe consists of dark matter and dark energy. And being dark, we cannot see or measure it. A bit like black holes, we can see the effects without seeing the actual entity.
Problem solved then? Well, yes and no. There is considerably more dark energy now than when the universe was young. From 0% to 72% is extremely significant -and shows that the laws of thermodynamics only apply to small volumes of space over short periods of time.
Why so significant? Well it would seem that when there was little dark energy was around, the universe was expanding at an ever slower rate. Eventually the expansion would reverse, and all matter would implode into a new super blob.
Now there is so much dark energy, the universe is expanding at an ever increasing rate. So much so, that in a couple of billion years or so, the only thing you will be able to see from any star in the Milky Way would be all the other stars in the Milky Way. All our neighbors would moving away from us faster than the light could get back to lighten our skies.
Since the rate of accretion of dark energy is known, and the effect of its ever greater presence can be tracked - as we look back in time by staring deeper into the outer reaches of the see-able universe, we are able to give the universe a date range of longevity somewhere in the range of 13.6 to 15.2 billion years.
But wait! - I hear coming from our local friendly fundamentalist - the universe is less than 10,000 years old.
Oh dear - do we have an irreconcilable difference?
Well, falling back on to our old chum semantics, there is a way out of this seeming impasse.
Since the fundamentalist's god can do anything, it is within his ambit to create a universe that is older than the moment of creation. Truly. Would you not agree that he could, in the next minute, create for us a 5,000 year old relic? We could peruse and marvel at it: for even though its linear age would be one minute, its objective age thousands of years older than that.
It would seem to me that if the universe really was created 6,000 years or so ago, it was created with an objective age of 14.5 billion years or so - to allow enough black energy to form to enable accelerating expansion..
The difference between theist and non-theist is that the non-theist opines all the events in that 14.5 billion year universe really did happen, but the theist holds that they did not happen. We can see only what would have happened if they had actually happened.
Take the case of primitive man who seems to have left traces of his passing tens of thousands of years ago - a time before the universe was created. By differentiating between linear age and objective age, theist and non-theists could possibly agree that the primitive tribes of 12,500 - 500,000 years ago have left evidence of their passage, even if that passage was created a mere 6,000 years ago.
It is so nice to find we can find common ground - particularly as at this time of year we all would wish to share common wishes of good-tidings to one and all.
Glad I could have helped. Happy New Year.