I came across an interesting observation today. Since early November 2000, there has been a continuous human presence on the International Space Station; ever since that date, at least one astronaut - male or female, from any of 17 countries - has been aboard the ISS as it orbits the Earth.

But the flip side of that fact is the point that is perhaps more intriguing, at least to me. That period, 18 years ago, marked the last time we were all together here on the planet. Sure, we still have the numbers, but not the totality - 7.699 billion here on Earth, and a handful up there in space, watching us from above as we watch from below.

The last time we were all together. It's a phrase that takes on more significance when you lose someone close to you. If you've been there, you know. You put the memories on a loop and watch them in your mind, for as long as you can stand.

It's been a year this month since my dad passed and nine years since my brother. And the grief subsides in time, but I'm not sure the sense of absence does. Now, all of us who are left get along, but the chalk marks are on the board - us here, and them there, until we meet again.

I honestly don't remember much about the last time we were all together, because I didn't know it was the last time. It was probably a regular visit. Sunday dinner, a ballgame on TV, maybe, or a nap on the couch. A group picture on the front porch and the exchange of see-you-soons.

There's that part of "Back To the Future," when the people in Marty McFly's family photo from the present day (1985) start fading away as he makes a mess of everything in the past (1955). Weird to think that we're three decades past that now.

But I think of all the backyard gatherings of those days, my 1985 - the July 4 fireworks, the birthday parties, washer-pitching, all the games of pig and horse on the home-built basketball court, and I watch all those people fade away too, out of the realm of Kodak-print reality and into the other sphere.

In this, I know, I am not unique. Look at the obituary page in this paper, or any paper anywhere. Every one of those people had a story. A family, perhaps, or friends left behind, or maybe only acquaintances, people who say "Oh, I remember him, he was the guy who used to..."

More than 150,000 people die every day here on Earth, according to World Health Organization statistics. They all had their stories too, some novel-length and some far too short. But life is short, isn't it? People being born and people dying, and in between living their lives the best they know how, finding great triumphs and utter failures, carrying on in the spirit of their own fathers and mothers and sisters and brothers and friends and orbiting, always orbiting, waiting for the next time everyone will be together again.