New Year's Eve should be an easy landmark to remember, but there are surprisingly few I can pin down with any degree of certainty.
Without any effort I have been able to recall the past four New Years. I know where I was at the turn of the Millennium and I'm pretty sure of the year I was on Copacabana beach in Brazil.
When I was in High School and home from college there was a party, usually where my friends and I went to drink. I have vague memories of my parents' parties when I was a child, mixed in with watching some TV programme when there was no party.
My memory of New Years covers nearly half a century. Mobile phones disappear as I venture back, as do ATM machines. The Berlin Wall returns along with the Cold War. DVDs turn to VHS tapes, our television fades to back to black and white. Our front-loading washing machine vanishes. Fruit and vegetables becomes seasonal and we wrap apples in newspaper and store them in the dark for the winter. There are rumours that the Beatles will reform - they broke up when I was five years old.
I now have nearly 400 images pinned to my internal calendar, stretching back day by day into 2011. In idle moments, I will sometimes take a trip through the past year by recalling the image for the same day of each month. This takes just 12 images and as the sequence depends on the date and is always building, it is usually fascinating.
Applying the same technique to recalling New Year's Eves only, I could jump back to being 5 years old in 42 images (if I had stored them). If I had been born a little earlier, I would have the 50 images required to cover half a century. Double that and we are back to the early days of flight, the lull before the storm of the First World War, radio and film as the new forms of entertainment. Women without the vote and no access to reliable contraception. The past is such a foreign country a little over twice my lifetime ago. Just one hundred images of New Years.
Add the same again and two hundred years ago trains and steam power are the new innovations. A century before and canals and horse-drawn barges are the transport system that powers the industrial revolution in Europe. If I could look back as many New Years Eves as I have remembered sequential days, I would be in a world where evolution had not yet been proposed and, in the Western world, God, the devil, spirits and demons controlled events on an Earth the most learned scholars state with certainty is just 6,000 years old.
Rolling back the calendar more quickly through as many New Years as I will see days in my life and I see civilisations explode then shrink, the pyramids deconstructed.
Further back still and I see our ancestors returning to Africa and decreasing in number until the first homo sapien is born to parents who are somewhat different.
Back further to a more hostile world with creatures only capable of shaping it consciously in limited ways, but whose respiration changes the atmosphere, whose bodies settle on ocean floors to give rise to chalk cliffs, whose swampy vegetation will create seas of petroleum millions of years in the future.
Back to when a splashing wave deposits a few cells on a rock where they dry in the sun and survive to reproduce. This has happened many time before, but the cells deposited in countless splashes over millions of years shrivelled up and died in the sun. Only now when the right cells splash onto the right rock at the right moment does life reach dry land.
Billions of years back now to the deep past and an ocean that is a chemical soup. Within it some of the molecules are very special. They grow and split, attracting other chemicals to protect them. Further back and they are less complex and fewer in number until there is the first - perhaps
formed at a deep sea hydrothermal vent. A molecule formed by chance or divine will, to act as the seed to transform the Earth and assemble some of its atoms into increasingly complex structures that will populate every habitat and ultimately gain self-awareness, the ability to think, to reason, to remember and to write blogs.
Perhaps three billion New Years ago the sequence of days leading to the days to which I am witness began.