Eventually, though, what matter hasn’t been swallowed by black holes will be spread so thinly through the void it will effectively cease to interact. Some theories suggest matter itself will evaporate away, neutrons and protons decaying over an impossible to comprehend length of time. The cosmic background radiation will cool till its wavelength is larger than what we now recognize as the visible universe. But whatever happens, due to the effect of vacuum energy, the universe itself will continue to expand, likely forever, becoming increasingly diffuse, cold, and dark, yet eternal.
The good news is we won’t be around for that part. Well, good news for me anyway. I’m already cold all the time, especially my feet, so I wouldn’t want to be stuck in a place where the last bit of infrared radiation was a trillion trillion trillion years in the past.
Of course, cosmological models are subject to change. Just this week I read about a theory challenging the idea that the speed of light is fixed and immutable. There’s a long way to go before the ultimate speed limit of the universe, determined by Einstein a century ago, is overturned—if at all. But the fact we’re even talking about it is evidence we still have a lot to learn. It’s not unreasonable to assume humanity itself will come to an end before we fully understand all there is to know of how the universe works.
The Big Bang is a relatively recent idea, but the concept of an eternal existence isn’t. In the late eighteen century, James Hutton, father of modern geology, said of the age of the earth, “we find no vestige of a beginning, no prospect of an end.” Theologically, at that time, things were a little more constrained, with the age of the earth (and therefore the universe) believed to be no more than mere thousands of years. Today, we know the Earth itself is nearly five billion years old, and the universe nearly 14 billion. Still, those are just numbers. In Basin and Range, John McPhee, notes that human beings can comprehend roughly five generations—about 100 years. Beyond that, we can only make measurements.
As a writer, no vestige of a beginning, no prospect of an end seems to be the defining characteristic of most of my work. (Maybe I shouldn’t devote so much thought to pondering the extreme limits of existence.) Still, I believe there’s a practical value to having my head in the stars, and my heart wandering the paths of deep time. Human experience may be bound up in the moment, or on the days ahead and behind us. But we all live in a greater reality. We’re all made of the same stuff, starstuff, as Carl Sagan used to say—and, for me, contemplating the myriad ways we engage with this reality is critical to writing characters with impact and meaning. It gives them life beyond the page, and in a way beyond my own imagination.
Taped to the wall behind my desk is something else from Basin and Range, a quote from an unnamed geologist that I reflect on again and again as I write:
“If you free yourself from the conventional reaction to a quantity like a million years you free yourself a bit from the boundaries of human time. And then in a way you do not live at all, but in another way you live forever.”