Sunday, 13 March 2022

Understand our Universe and our physical reality - Lent 2022, Day 12

Not long ago, certainly in my childhood, it was believed that science had all the answers. There were a few loose ends to tidy up (such as reconciling Einstein's general relativity with quantum mechanics into one unified theory, and determining whether we had a steady-state Universe or had it come into being with the Big Bang). But generally, reductionist materialism was the orthodoxy, and to believe in anything else was just cognitive dissonance - wishful thinking, pseudoscience. 

Today, scientists will admit there's more and more that they know they don't know. The very boundaries of physics are being questioned. Is our Universe one, or are there several universes, or many, or an infinite number of them? How did the Big Bang happen - and what came before it, and how will our Universe end? What is consciousness? An illusion? An emergent property of the evolving brain? Or a fundamental property of matter, along with mass and charge? Why are the fundamental physical constants as they are? Had they been even slightly different, we wouldn't be here to observe a Universe that seems to be fine-tuned to accommodate us.

Quantum mechanics is approaching its hundredth birthday, and while it works, providing the theoretical and practical underpinnings for the past century's technological advances, understanding it remains contentious. No fewer than fifteen different interpretations vie for general acceptance.

Cosmology is in a similar state, especially when we consider philosophical cosmology - what is the first cause of the Universe? Why does it exist, rather than nothing? What are the ultimate, irreducible material components of the Universe? Could a different Universe exist with different physical constants to those that govern our Universe? Does it serve to have a purpose, or is it just there? What is the totality of our Universe - or indeed all universes?

Physics gives a broad choice of possibilities. The multiverse hypothesis posits the existence of more than one universe, from few to an infinite number - call them what you will - alternative universes, parallel universes. Throw into the mix string theory - in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. The scientific jury is still out.

Over the past year, I've been watching an increasing number of popular-science videos, such as the Royal Institution lectures, PBS's series Space Time, Sabine Hossenfelder, and History of the Universe, as well as the science episodes of Closer to Truth. I am particularly interested by those videos about the subjects where science is still uncertain - and I can see just how divergent scientists currently are when it comes to the great unknowns. The phase of the Big Bang known as inflation and the conformal cyclic cosmology are two that I've recently followed, theories that divide science.

So - we know that we don't know where we are. In the one Universe, or one of many? In its one lifespan, or in a repeating cycle? We also know that we don't know how we got here. We still don't know for certain how life began. 

But I feel, I intuit - and have done since childhood - that there is a purpose why we are here.

This time last year:
Faith and knowledge

This time two years ago:
Religion and feeling good

This time four years ago:
Perivale Triptych

This time 11 years ago:
Cycling and recycling

This time 12 years ago:
Winter still holding out in the forest

This time 13 years ago:
Little car, huge price

This time 14 years ago:
Old school Łódź

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