If you are over the age of about 55, chances are you don’t just remember the Apollo 11 moon landing, you also remember exactly where you were when you saw it.

So, if you were at school on July 21, 1969, you may also able to recall the look of the TV set itself, the name of the teacher who wheeled it out in front of the class and the spirituous smell of the faint blue Gestetner-printed handouts.

Magda Szubanski can clearly recall being marched out of class as an eight-year-old and “herded into the sick bay” to watch the men on the moon. She also remembers being told to “shut up” by her teacher, Mr Arblaster, for chattering too much about the astronauts and their historic mission.

Meanwhile, at the Australian army base in Nui Dat, Vietnam, singer-turned-soldier Normie Rowe was repairing an armoured personnel carrier. He has a clear memory of the transistor radio he listened to the lunar landing on — it was National brand and had cost him $5.

Then-student activist and now Labor politician Meredith Burgmann can describe the Pye TV set that sat in the corner of her share-house in inner-Sydney Glebe and beamed those images in. They invited the local postman in to watch and have a cup of tea. “It was absolutely incredible,” she recalls.

Bert Newton was hosting the variety TV show In Melbourne Tonight from Puckapunyal army base in Victoria. He remembers eating a cheese sandwich as they stopped rehearsals to watch the Apollo mission. He says the audience that night was the best he’s ever had.

Australians flocked to televisions en masse to glimpse the moon landing. Photo: State Library of Western Australia

Why we remember this so clearly

In the late 1970s, psychologists Roger Brown and James Kulik coined the phrase “flashbulb memories” to describe the phenomenon of remembering not just the event itself, but small, seemingly inconsequential details surrounding it.

A flashbulb memory is created, Brown and Kulik argued, when there is “a high level of surprise, a high level of consequentiality, or perhaps emotional arousal”.

It’s easy to see how Armstrong and Aldrin’s first moon landing was “consequential” as a first for humanity — it wasn’t really a surprise given it came seven years after President Kennedy promised it would happen, but it certainly involved plenty of emotions.

There was the poignancy of knowing Kennedy hadn’t lived to see his bold promise fulfilled. There was the sense of danger — the launchpad fire that had engulfed Apollo 1 in 1967 and claimed the lives of three astronauts. And there was sheer excitement at seeing something that had never happened before in the history of mankind.

In more recent years, scientists have suggested a biological basis for that kind of memory formation, involving the release of the “fight or flight” hormone norepinephrine.

It primes our brains to remember everything we can about an unexpected, emotional or dangerous event. The colour of the chairs outside the school principal’s office. The pain of a grazed elbow after falling off a swing. The song that played as you first kissed your partner. The faint smell of the Calla Lilies on the coffin of a parent.

Subsequent research has supported the existence of “flashbulb memories” while at the same time noting the way they can become blurred over. Memories are not literally snapshots, they are not permanent nor impervious to subsequent information.

Scientific debate continues about how and why we remember certain things and not others. The human brain it seems still contains almost as many mysteries as the universe.

But researchers agree it is a characteristic of such memories for individuals to have a high level of confidence in them, and that’s part of the delight in sharing our “where were you when…?” stories.

A collective memory

Our memories tell us and others something about ourselves. And when our memories overlap with others’, they have a uniting effect.

Unlike many of the tragic events, like the death of JFK or September 11, that trigger collective “flashbulb memories”, the moon landing had an almost universally positive effect.

In 1969, Andy Thomas was a teenager in Adelaide, watching awestruck as Armstrong and Aldrin kangaroo-hopped in the one-sixth gravity of the moon. He turned that wonder into an illustrious career at NASA.

Megan Clark was allowed to stay home from primary school in Perth, and watched the moon landing cross-legged on the floor with her brother as her parents sat on the green sofa. She’s now head of the Australian Space Agency.

John Howard was a 29-year-old solicitor in Sydney; he says the moon landing proved that with hard work and talent, anything is possible. He later became Australia’s second-longest serving prime minister.

Buzz Aldrin is pictured on the moon’s surface in a photo taken by Neil Armstrong. Photo: NASA

Passed down through generations

For those like me who are not old enough to remember the moon landing, we’ve often inherited the stories of our families and friends who were there.

July 21, 1969, was my grandfather Jack’s 70th birthday.

After lying about his age to enlist, he’d spent his 18th birthday as a machine gunner on the Western Front in France, shooting at rickety German biplanes made of canvas, wire and wood.

How incredible then to be seeing men on the moon barely half a century later on a glowing box in the corner of his own living room, eating sponge cake and bouncing his baby granddaughter on his knee.

Later, when I knew him, Jack would talk about having lived long enough to see that day in July 1969, but never about the war he had witnessed as a teenager.

That’s the other thing about memories — some you spend a lifetime trying to forget.

-ABC