Soon, I plan to publish an article in which I’m going to try to persuade you to consider something that you may well find unbelievable. Before I do that, I think it might be helpful to ask you to think about some other incredible concepts.
In the clip above (taken from a TED talk ‘Why is our universe fine-tuned for life?‘) , Brian Greene explains how it is that we live on a planet that is just the right distance from our sun to sustain life as we know it; not too close, and not too far away — the ‘Goldilocks principle‘. But he does more than just this: he talks about how Johannes Kepler spent a great deal of time trying to figure out why it is that the Earth is 93 million miles from the Sun — which turns out to be the wrong question.
The right question is: “Why do we humans find ourselves on a planet at this particular distance instead of any of the other possibilities?”. The answer turns out to be, quite naturally, “it yields conditions vital to our form of life”. (This is the anthropic principle.)
Hold on to your hat: the rabbit hole goes deeper.
(Our current understanding is that) our universe is expanding. But even more importantly: the rate at which it is expanding is accelerating. At some point in the far distant future, all of the other galaxies in our universe will have receded from us so far, and so fast, that it will be impossible for anyone to perceive them. As Brian Greene says in the same TED talk:
… because the expansion is speeding up, in the very far future, those galaxies will rush away so far and so fast that we won’t be able to see them; not because of technological limitations but because of the laws of physics. The light those galaxies emit — even travelling at the fastest speed, the speed of light — will not be able to overcome the ever-widening gulf between us.
So astronomers in the far future, looking out into deep space, will see nothing but an endless stretch of static, inky, black, stillness. And they will conclude that the universe is static and unchanging and populated by a single central oasis of matter that they inhabit: a picture of the cosmos that we definitively know to be wrong.
Now, maybe those future astronomers will have records handed down from an earlier era, like ours, attesting to an expanding cosmos teeming with galaxies, but: would those future astronomers believe such ancient knowledge? Or would they believe in the black, static, empty universe that their own state of the art observations reveal? I suspect the latter.
Which means that we are living through a remarkably privileged era when certain deep truths about the Cosmos are still within reach…
So we are alive at a point in both space and time that allows us to examine the Cosmos in a particular way — that may, or may not, represent the ‘truth’. Brian admits:
… when we learn that astronomers of the far future may not have enough information to figure things out, the natural question is: “maybe we’re already in that position”.
It does my head in :)
Here’s that TED talk in full. It’s 22 minutes long, and I found parts of it quite difficult to follow, but well worth the time.