Can’t sleep. Guess spending most of the last month in a mild doze has taken up all the sleep for a while. I’ll have to get at least a little though, stuff to do tomorrow and I need to get something vaguely resembling a stable sleep cycle by next week. I know how to fix this, wine & philosophy. I even have some chocolate if things get desperate.

Here’s a thought that blows my mind. The universe is 13.7 billion years old, and 48 billion light years in diameter. This means that, averaging since the beginning of time, the distance between the far edges of the universe grows at nearly twice the speed of light. Yet no object can move faster than light relative to any other object.

What’s happening is that spacetime itself is expanding. This is a difficult concept to wrap my head around, and I’m still not sure I get it, so bear with me. The usual simile I’ve read is a balloon with dots on it. As the balloon inflates and expands, the dots spread farther apart. In the same way, galaxies spread farther apart as spacetime expands. In every direction at once. I’m starting to get a headache again. 

When I was a kid I read astronomy books that talked about the Doppler Effect, the tendency of waves to spread out or contract with relative motion. It’s why car horns or train whistles change pitch as they pass you, and how police radar guns calculate your speed. In light waves, the effect shifts them toward blue if they’re approaching or red if they’re retreating, so in our expanding universe distant objects appear red-shifted.

The books I read as a child talked about very distant objects whose Doppler shift was so far in the red that they seemed to be receding at nearly the speed of light, which was a puzzle to astronomers. Now we know why, it’s because the space in between is expanding, stretching the light into the red.

The implications of this are just staggering to me. There will come a time when it will be impossible to directly observe evidence of the Big Bang, and people who live after that point will have to rely on the observations and measurements of those of us who came before them. At this point the universe will be a trillion years old, a hundred times as old as it is now, and still have almost all of its star-forming years ahead of it.

As profoundly ancient as the universe seems to us, we live in the early times. We are the ancient precursors, who knew the universe when it was young. Appreciate that for a moment. On the cosmic scale, things are just beginning. The orchestra hasn’t even warmed up yet.

And there’s already so much! I once saw a 3D model that was filled with points of light in strange, stringy clusters. I had no context for the image, I didn’t know what I was seeing, but I thought it might be stars. I eventually learned that it was a model of the known universe and those countless points of light were galactic clusters. Hundreds of billions of galaxies each containing hundreds of billions of stars.

In all that vastness of space and time, covering distances and quantities so huge that they’re almost meaningless numbers, the countless wonders that we find everywhere we look, the timelines so long that I casually rounded off the entire age of the universe, in all of that, you are unique. For a brief span of flickering decades, the universe contains you. There’s only one of you in all that space and there will never be another in all that time.

The uniqueness of each person is an amazing thing to me. Just think how lucky we are that in that mind-numbingly huge sea of space and time, you and I exist together. How fortunate we have been to have the chance to interact, perhaps even meet each other. If one of us had been born a thousandth of a percent of merely the time already elapsed sooner or later, we would have missed each other by 137,000 years.

I’ve said before that when I hear people pondering the scale of the universe and saying it makes them feel small and insignificant that I disagree. I suppose I’m just self-centered in that I judge everything else by my size, not myself by everything else. But I do feel profoundly affected by the comparison, because it highlights to me just how rare and precious we are.

There are only seven billion of us, clinging to the skin of this little world in a terrifyingly fragile ecosystem. All it would take is a gamma-ray burst, or a close pass with another star, or an asteroid impact, or even a big enough solar flare, and we’d be gone forever. Extinct. Given the vastness of the cosmos, anyone else living out among the stars would probably never find us. The universe at large would never know we had ever existed.

So please, I beg you, cherish humanity. There’s no sign that anyone else is going to save us from ourselves, so we have to take care of each other.