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Sep. 22, 2020 | Tuesday
Editorials and Opinions
Dr. Brown: When the lights go out in the universe
Dr. William Brown.

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the Infohealth series held on the second Wednesday of each month at the Niagara-on-the-Lake Public Library.  

Dr. William Brown

Special to The Lake Report

Entropy is hardly a household word. It certainly wasn’t one I knew much about until I began to develop this September’s library lecture series, "Physics: The Camelot Period 1900-1930.”

As prologue for the series, which starts Sept. 16, I needed to look back to the 1800s. Most of us are familiar with the fathers of evolutionary theory, Wallace and Darwin and much less so with Faraday and Maxwell – pioneers in electromagnetism. But it’s a rare person, outside of physicists and engineers, who are familiar with thermodynamics – the science of heat and energy.

Thermodynamics – the study of heat – began in the Industrial Revolution, especially with the development of the steam engine. At the outset thermodynamics was all about the efficiency of steam engines.

But it is the second law of thermodynamics that is important for today’s column. This law states that energy comes in two forms, one of which is usable and the other disorderly and, more important, inaccessible, or in the language of thermodynamics, entropic.

Beginning with the Big Bang, moving forward to the present and trillions of years into the future, the fraction of the universe’s energy that is unusable has and will continue to increase, although the net sum of the energy, usable + not usable, will remain the same. (That’s what the first law of thermodynamics says: no overall loss of energy; even if as the second law states that the fraction of the universe’s energy that is entropic, increases with time.)

Take stars, for example. The intense gravitational forces that form stars in the first place, create enormous pressures and temperatures, which working together in the star’s core, are sufficient to fuse trillions and trillions of hydrogen nuclei into helium nuclei per second.

In the process, tiny bits of matter are transformed into enormous amounts of energy (nuclear fusion). The reason? Remember Einstein’s most iconic equation – E(energy) = m (mass) x c2 (the speed of light squared).

Most of the latter energy comes in the form of photons of light generated in the star’s core from which it eventually reaches the surface of the star and creates the light that baths surrounding space including in our case, Earth. Without that there would be no photosynthesis, no plants and no us.

The synthesis of more complex heavier elements continues through to iron for many stars beyond which further synthesis of heavier elements requires the far more intense pressures and temperatures typical of supernovas or other horrendous events such as collisions of neutron stars, for their creation.

So well, nucleosynthesis and the creation of more complex elements reduces entropy somewhat, there’s a net loss. Why? Because an enormous amount of that energy released by the sun is dispersed – wasted if you like – and no longer accessible (increase in entropy).

In a like fashion, the creation of life and the increasing complexity of life (analogous to the increasing complexity of atoms through nucleosynthesis), requires a lot of energy, which becomes less accessible with use and increases entropy.

For the very long term – possibly for trillions of years to come – the energy economy of the universe will continue to provide enough low entropy energy to sustain the formation of stars and thus light and heat to keep the universe and anthropomorphically speaking, life humming.

But eventually the math and probabilities of the second law of thermodynamics will catch up with the universe. With the result that some time in the distant future there won’t be enough accessible usable energy to keep stars forming and for those present, all will run down – this time around – with no replacement. That’s when the lights go out in the universe.

That is unless there’s another cycle of creation – a new Big Bang – a new injection of energy into the system. Perhaps that’s what happened when our universe began.

It may have signalled the end of a previous universe or perhaps an infusion of energy might come from other universes with which ours coexists, but which are out of reach of any tools we have to see them. I used to think the whole idea of multiverses was crazy, but like Einstein, who couldn’t accept an expanding universe until the evidence was overwhelming, I might be wrong about multiverses.

Meanwhile, we continue to waste energy, converting more and more energy into inaccessible forms of energy for eternity and spoiling the planet and life in the process. That is where we’ve been headed for much of our history.

But at least in the early days, there weren’t many of us and the damage was minor. Now, with seven billion humans and counting, surrounded by inefficient energy-consuming devices and toys, we really have the tools and numbers to do serious damage to our communities and planet, to say nothing of our fellow creatures, great and small. It looks like a lot more entropy to come.

Something to think about and act on.

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