Forty years ago today, I sat in my family’s living room in San Jose, watching ghostly black-and-white images and listening to a message from as far away as any message ever delivered by a human voice.

The little things are what I remember; the furniture, where the tv sat. The color of the drapes. And my brother’s screaming tantrum, while Neil Armstrong said one small step.

The universe changed. The sci-fi world inside a seven year old boy’s head was, suddenly, real, and possible.

All of us have moments that sear into memory forever; in a real way, moments that define generations. Where were you when Kennedy was killed, people used to say, for the generation just before me. My parents told me about about hearing serious, breathless voices reporting over the radio – A day that will live in infamy. Some of you, younger than me maybe, talk about Kurt Cobain’s death that way, and almost everyone I know over the age of 10 remembers the exact instant when heard, or saw, or read about two planes hitting two towers in New York City.

Some of these moments change the world; some only define a generation. I say only as if that carried less significance; yet for some, the death of Elvis or Janis, Buddy or Kurt or Jimi, Jim or even Michael, may be the day your music died. The point is that they’re those moments we will always remember, for whatever reason. Time and place and feeling burned like a brand into us.

But some of these moments, in a real and permanent way, do change the world. Who knows, when Admiral Isoroku Yamamoto sailed his fleet of aircraft carries toward an archipelago in the middle of the pacific, if he had any inkling that he was steaming toward the hinge point in the most significant war of his century, possibly the most significant war in human history. The nineteen hijackers in 2001 may have been in the grips of some delusion of grandeur; personally, they were simply fools attacking an irrelevant symbol, for the imagined glory of a mythical god. Yes, they cost many lives and billions of dollars; but the impact that lasts, decades later, will be changes to the political and social landscapes of the United States, the middle east, Europe; in a sense, the entire world. Industries were permanently changed. The word Terrorism entered the daily lexicon of ordinary people. Governments fell.

Violence, fear, destruction, and death defined both of these events. And ripples continue to roll outward from them; even now, 64 years later, Perl Harbor and WWII still define much of the relationship between Japan and the USA.

But some events change history, not with destruction, but with creation.

June 20, 1969, an entire world looks up at the moon, physically, or virtually, and say, we’re up there. Men stand beyond that unimaginable gulf, we realize; they may be looking up into their own sky, and seeing this blue and green ball. They may be walking, leaving footprints where no living thing has, ever.

Children looked up and said, I have no limits. I can go up, and never stop. I can fly. Men and women looked up and said, that’s why I do what I do, making what I make, learning what I learn. For one moment, we had won an almost inconceivable battle. We’d done the impossible. We waved flags and claimed a victory in an imaginary race, but every pair of eyes, every pair of ears, every mind that was in any way able to hear or see or read Neil Armstrong’s words, knew we’d just won some intangible victory over space and impossible odds.

Every scientist I know, every engineer, every writer or teacher or pilot; every one who was old enough to know men stood there above our heads, felt things change around them. We felt the limits move unimaginably far back.

We could do anything.

The generation who witnessed that moment went on to invent almost every single thing upon which our lives depend today. Medicines, weapons, tools. Computers, networks. We invented ways to fly, ways to go to space, ways to live in space.

And ways to die, tragically and pointlessly; proving that no matter how many years have come since, space is still a dangerous place, a place we don’t belong.

I was seven years old when Michael Collins, Buzz Aldrin and Neil Armstrong lifted off a launch pad at Kennedy Space Center, and already, I lived only for space and adventure. I played with my G.I. Joe space capsule, watched Star Trek and Lost in Space with my father, and knew, beyond a shadow of a doubt, that I would be up there one day.

At 7:39pm PST on Sunday July 20, 1969 (forty years almost to the minute, as I type this), my family were clustered around a TV set that seems absurdly small now, watching a picture that was all but incomprehensible with snow and interference. And I was as glued to that image as I ever have been to anything, before or since.

Behind me on the couch, my brother Ian – five and a half years old – was in the middle of a screaming tantrum. He’d given himself a nose bleed, and, twenty nine years before the invention of TiVo, was demanding at the top of his lungs that we make the TV wait until he could watch it.

My memory of the event is rich in detail. Ian’s insane screams and wails, my parents frustration as he distracted them from the event; my own confusion and elation, (and irritation) as I tried to make sense of the snowstorm on the TV and Armstrong’s brilliant, nonsensical, unforgettable quote over my brother’s howling.

That night I lay in my bed, looking at G.I. Joe and Major Matt Mason, and all my other space related toys and books, and I imagined heroic men in space suits cooler than anything artists or toy makers could think of. I wondered what they were doing, where and when they slept, what they ate, and how they went to the bathroom.

Over the next days, I watched every piece of television news I could get; I read the papers with my parents. I ate and drank and dreamed words like Apollo, Eagle, LEM, Mare Tranquillitatis, Command Module.

I’m not sure, once the country had gotten used to the idea, gotten over the wonderment, that most of us really knew how much human history has just changed. I’m not sure most americans, busy with work, with school, with getting by, scoring, getting laid, thought about the hardware left behind in the deep thick dust, about the men who’d gone up there, about the ones on the ground working non stop to get back again, only better, and safer.

But for a generation of children and young adults, that was all we thought about; the gateway that had just opened. The fundamental difference the universe had after.

Eight years later, Star Wars premiered; movie makers who’s sat in front of their televisions like I had, had turned it into mythology that would leave it’s own explosive impact. That same year, the first space shuttle, named Enterprise by science fiction fans and young man who lived and breathed space ships flew it’s first test mission, as far beyond the Gemini and Apollo craft as they were beyond bi-planes.

In the years following the Apollo program, technology advanced in almost every field upon which the high tech industry depends. The study of power, physics, heat; battery technology. Things as basic as the teflon that coats our pans, the chips that drive digital wacthes and iPods and cell phones. Aerodynamics which are used everywhere from airplane design to cars to bicycles to speeding up swimmers in the water and skaters on the ice.

There’s been a great deal of dark history for Nasa and the space program in recent years. Budget cuts in the mid seventies caused stagnation in culture and technology; we’ve seen two massive, entirely preventable shuttle disasters, and no forward progress on what’s next in decades. Nasa, like any under-funded, over-worked government agency, began to make choices based on protecting itself instead of reaching out and up. Today we fund Nasa at a fraction of the (effective) budget they had to spend in the mid sixties; and worse, we began to say, as a culture, space? it doesn’t matter. We felt we needed to worry about here and now and how I’ll pay for a tank of gas.

Today, while I should have been catching up on work, squashing bugs after some weekend network updates, I instead watched videos of the Lunar Module docking with the Command Module, remembered building plastic replicas of them with polystyrene and glue and paint.

I’m not sure when I, personally, said goodbye to my certainty that I’d walk up on the moon some day. Maybe it got lost in my adolescent discovery of girls and music and drugs; maybe it was when I realized that astronauts weren’t the daredevils of fiction, but in fact were dedicated students and military men. I wasn’t a good student, hating authority and having no attention for anything that wasn’t interesting to me at that exact moment. I never forget that dream though; when I glide through deep water, the images of men and women in zero g comes to mind. When I watch video of multi-billionaire ‘space tourists’ visiting the international space station, I feel a searing envy, not over the money they have to waste, but that they have what it takes to go out to the far frontiers of human experience.

What changed in 1969 was that, for the first time in human history, we were there on the outer edges with adventurers and explorers. No one saw Richard Francis Burton search for the source of the Nile; no one but a few sailors were witness to Captain Cook’s ‘discovery’ of most of the islands in the south pacific. And in both cases, the discovery was one culture finding what another culture already knew.

But in June of 1969, an entire world watched and listened, in real time, as one single foot stepped on a square foot of dust no human foot has ever trod, no human eye had ever seen. And we knew it minutes after the explorer himself. The world of 1969 was decidedly short on frontiers; Neil Armstrong and his compatriots defined, for every human being alive, where the frontier was.

It’s going to be a long time until someone moves that line. When it moves, the universe is going to change again.