Saturday, 10 December 2011

Putting things in perspective

If I’ve done my sums right:
There are 31,536,000 seconds per year.
According to modern cosmological theory, the universe is 13,500,000,000 years old.
So since ‘time’ began, there have been 425,736,000,000,000,000 seconds.
According to Prof Brian Cox, “As a fraction of the lifespan of the universe … life, as we know it, is only possible for one thousandth of a billion billion billion billion billion billion billion billion billionth of a percent.”
That is to say,
of its total duration.
The shortest period of time possible is reckoned to be a Planck Moment which is 1/10,000,000,000,000,000,000,000,000,000,000,000,000,000,000th of a second.
Since the Big Bang, there have therefore been
4,257,360,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Planck Moments.
Thus, according to these figures, if the percentage of the total life of the Universe during which life is possible were expressed as a fraction of time since the Big Bang until now, it would last approximately 0.000000000000000000000000000043 of a Planck Moment. Give or take.
( I’m preaching on Ecclesiastes at the weekend, which I think is a great book for putting life in perspective.)
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  1. But, by definition, Prof Brian Cox speaks the Truth, because he's a telly personality. And he once made a record. And he's pals with St Patrick Moore.

    John, you must have got your sums wrong.

  2. Thanks Richard - I think I may not have made myself clear! I was trying to do a 'What if the entire timespan of the universe were a clock, how long before midnight would life appear?' thing, but decided to use the timescale of the entire universe until now as the 'clock'. So that's where the final figure comes from.

    (Perhaps I should have stuck to the clock analogy!)

  3. I didn't hear Brian Cox say that, but if he did, he's wrong. It's reckoned to be about 1/3000 of the age of the universe.

    But given that sort of number, it's possible he was talking about either the size of the universe or having some kind of cycling universe model with the constants reset each time, in which case his point was an Anthropic Principle one. But the cyclic universe doesn't work anyway.

  4. What a privilege to be able to dovetail with your fine daily Bible study notes on Ecclesiastes in "Explore".

    David Brock

  5. Thanks David. BTW if you keep your eyes open, I'm teaching four Wisdom books in the New Year as a module for the Diocesan Course in Christian Studies.

  6. PS I meant to say that would be at Audley End.

  7. John,

    Sorry if I confused you. My comments were rather more ironic than serious. Brian Cox should, above all people, know how many billions to put in his calculations and he appears to have exaggerated the length of something here. As I understand it, he was trying to put the insignificance of human life down to about a 10(-86) part of the supposed life of the universe. Such regard for the importance of human life he has.

  8. You left out the most important factor. It's intended to be measured against the total durationof the universe...not just until the present time. Try figuring it again with the life span of the universe being ten to the hundredth power, instead of 13.7 billion years.

  9. Denise - not really. What I've done is take the fraction Brian Cox refers to with respect to the 10 to the hundredth duration and express it against the actual duration to date. It was intended to be like those illustrations which say things like "If life had existed for 24 hours, human beings would have appeared at two minutes to midnight" (or whatever).

    I'm sorry if that wasn't clear.