Understanding Geological Timeframes (and other massive numbers)

With the talk of global warming having “heated up” as we approached the Copenhagen conference, we’re seeing more talk around what can happen in different timeframes. So, although this is somewhat off my normal range of business topics, given the critical importance of Copenhagen to our future, I hope you will forgive this tangential post and find it nonetheless interesting.

I don’t know about you, but I’ve always had difficulty contextualising geological timeframes – millions and billions of years – as I could not visualise them.  How can one understand, say, 65 million years (approximately when the dinosaurs disappeared)? So I set out, some years ago when doing a geology course, to find an easy way to express these in terms that made sense to me.

Hopefully this will make sense to you too. Of course, if you don’t accept the underlying premise of the earth being billions of years old, then this post is not for you.

So – to the background.

The basic assumption here is that the world is around 4.5 billion years old (we don’t need an exact number for the visualisation – so this is close enough).

Interestingly, somebody of the biblical threescore years and ten (70 years old) has lived a little over 2.2 billion seconds (70 x 365.25 x 24 x 60 x 60). This points to a really handy scaling mechanism: we can equate the earth to a 70 year old person – meaning that each second in that person’s life equates to 2 earth years for scale purposes.


  • 100 years in earth terms is the equivalent of 50 seconds in that person’s life (let’s call it a minute for ease).
  • 1000 years is 500 seconds, or a little over 8 minutes, so 2000 years is approaching 17 minutes ago.
  • 100 000 years is about 14 hours, so that the period when modern man left Africa (about 70 000 years ago) is less than 10 hours ago, and Homo sapiens emerged a little over a day ago (200 000 years).
  • 1 000 000 years represents less than a week in our person’s life (5.8 days), and 100 000 000 years represents only about 1.6 years, so the dinosaur extinction of about 65 million years ago happened just on a year ago.
  • And a billion years is approaching 16 years in the person’s life.

One can apply this scale easily to any geological timeframe. It also helps understand why nature is not exact. So, for example, although the Supervolcano currently underneath Yellowstone seems to have erupted every 600 000 years on average, and the last eruption was 640 000 years ago or so, this does not mean it will erupt in our lifetimes – they are, after all, only 35 seconds long on this scale, and what is the likelihood of any event happening in 35 seconds?  

I hope this makes it easier to contextualise, understand and explain these massive timeframes.

Of course, you can use the same scale for other massive numbers: for example the current US National Debt is something over $12 Trillion, or close to $5 500 for every second a 70 year-old person has been alive (or $11 000 for every second a 35 year old person has been alive) – now these numbers are truly scary!

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3 responses to “Understanding Geological Timeframes (and other massive numbers)

  1. Get stuff more into perspective this way! Great Guy! 😉

  2. Interesting way of looking at global warming.

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