Saturday, 17 February 2018

Entropy and anti-entropy in a constant-ruled Universe

Lent 2018: Day Four

The Second Law of Thermodynamics is concerned with the direction of natural processes. It asserts that a natural process runs only in one sense, and is not reversible. For example, heat always flows spontaneously from hotter to colder bodies, and never the reverse, unless external work is performed on the system.

Place a mug of hot tea on your desk, leave it for long enough, and it will cool to room temperature. Energy runs down. This is entropy. We age, we die. A freshly picked strawberry eventually rots. It's a one-way process. All of this suggests that our Universe is winding down.

Yet it isn't. The Universe is expanding at an accelerating rate (something scientists only discovered 20 years ago). This is due to something we've not been able to prove or quantify - something that science calls 'mysterious' - dark energy. It comprises 68.3% of all the energy in the entire universe.

Stuart A. Kauffman makes the connection. "The implication of this accelerating expansion is that we do not have to worry about enough free energy. As the universe becomes larger, its maximum entropy increases faster than the loss of free energy by the second law, so there is always more than enough free energy to do work."

Since the Big Bang, 13.8 billion years ago, the Universe has become vastly complex - never mind the fact that it spawned us - marvellous, sentient, creative creatures capable of abstract thought - the observable Universe contains some two trillion galaxies, containing more stars than there are grains of sand on earth. [How much life could be out there! How much of it sentient! How much of it more advanced than us!]

Kauffman points out that this complex Universe is ruled by constants. "The laws of physics, general relativity, and the standard model, have about twenty-three constants of nature, such as the speed of light, the ratio of proton to electron mass, and so on. Were any of these constants very different, we could not get a complex universe with stars, galaxies, complex chemistry, and life. This is called the 'fine tuning of the constants'." [Do read this Wikipedia entry - it really is mind-blowing!]

So we are not living in a Universe that's winding down. Indeed, the opposite is happening, Kaufman says: "As more complex things and linked processes are created, and can combine with one another in ever more new ways to make yet more complex amalgams of things and processes, the space of possible things and linked processes becomes vastly larger and the universe has not had time to make all the possibilities."

Our Universe, expanding at an accelerating rate, is powered by dark energy, growing in complexity, complex systems are spawning even more complex systems - this is not entropy, this is anti-entropy. "The Possible becomes Actual, and this enables what next becomes Possible," and so on.

The mathematics of those possibilities, ponders Kauffman, boggles the mind. Let us consider all the carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur atoms in the Universe, and all  the possible combinations of molecules, forming amino acids, then proteins. How many times would we need to repeat the history of the Universe to form all possible proteins up to 200 amino acids in length, asks Kauffman. (His answer - ten to the power of 39 times).This all suggests that our Universe is non-repeating.

That's a mind-blowing thought. Repeat Big Bang billions upon billions of times - and there will not be another Universe like this one - ever!

This time last year:
Truth, spin, bullshit and lies

This time two years ago:
How much spirituality do we need?

This time five years ago:
The Chosen Ones

This time six years ago:
Fixies in the snow

This time nine years ago:
Just the ticket

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