I finally got round to watching this film yesterday on telly, and it was reasonably enjoyable drivel, much as I expected.
What annoyed me was the idea that if Jesus and Mary Magdalen had had a daughter, there would only be one surviving heir today. Assuming that each person has two children who go on to have children themselves, and that there are thirty years between generations, a person born in 40 AD could have, in theory, about 70 billion billion descendants by now. This is considerably more than the entire world population and an impossibility of course, but whatever the number is, it would be a lot more than one.
Not satisfied
1 hour ago
15 comments:
Well, unless the film (haven't seen it, don't want to see it) is a zombie movie (and if it were, those zombies would need to be eating the flesh of the living I imagine), many of the descendents should be dead by now.
If we take your assumption of 30 years between generations and I'll say that jesus was born exactly 2000 years ago (coz its a nice round number):
2^(2000/30) = 111,840,142,362,796,301,030 possible undead descendants walking the earth seeking the flesh of the living.
Right, well if that's not yet a movie then I claim film rights. Seriously though, lets assume a lifespan of 55 years. How do we work that in to our equation?
Well *I think* we would have to say:
2^((2000/30) - (2000/55))
which is actually 2^30.3 =
Roughly 1,321,931,247 *ultra fertile* people.
But of course, not all of them might have been able or wanted kids and some might have had less than 2 kids, so lets remove about ... a third? So we arrive at:
2^20.3 = 1,290,948 people descended from someone alive around 40AD.
P, I worked on basis of 2^66 to get to 72 billion billion.
You could also assume that after one century you have 8 surviving great-grandchildren (ignore children and grandchildren) (2^3), so after a thousand years, you have 8^10 surviving descendants = one billion, after two thousand years you have one billion billion.
So it makes a difference whether you assume 30 years or 33 years between generations, but either way the figure is ridiculously large.
Hi Mark,
I think the factorial should cover that:
0th generation: 2
1st generation: 4
2nd generation: 8
3rd generation: 16
and so on ...
then as long as you minus your estimate of the average lifespan and gap between generations (both of which have a large impact certainly), you should be okay.
I'm far more interested in the correct calculation to eliminate the people dead (those zombies will have to be killed somehow!) to find the surviving descendants, because that's what we're really interested in.
Do you think the calculation:
2^(generation span - lifespan)
covers it?
P, I think it's 2^(centuries elapsed ÷ generation span), you can maybe double it to work out surviving relatives who are already past child-bearinbg age, but that's a minor issue, seeing as with a 30 year generation gap you get a number 72 times as big as with a 33 year generation gap (and the generation gap could be anywhere between 15 and 45).
Quite a lot of the people alive back then have no descendants.
Everyone alive then is either the ancestor of every living person (bar a few remote communities like the Andaman Islands) or the ancestor of nobody.
R, "desendant" not "ancestor", surely? and yes, while it is highly unlikely that I am descended from somebody who lived in China or Australia two thousand years ago, I wouldn't be surprised if I were descended from well over half of people alive in Europe at the time.
What's missing from your Da Vinci Code equation is a variable governing the willing suspension of disbelief.
After all, the natural laws of mathematics surely cannot operate in a universe where it takes a detective and a trained cryptographer at least five pages to spot that a text is written backwards.
?txet hcihW
Not sure exactly - it's somewhere near the beginning of the book, but I kept falling asleep so I gave up. I just remember being astounded that the heroes could be so slow on the uptake.
Give me 'The Day of the Triffids' anytime!
", "desendant" not "ancestor", surely? "Now, I was referring to people who were alive 'then' as in 2000 years ago.
Whilst Australia was probably too isolated for them to be ancestors of current Europeans, China wasn't. With all the Eurasian hordes from the Huns through to the Mongols there was probably a sufficient flow of genes for Chinese people of 2000 years ago to be among the descendents of modern Europeans.
R, oops, I misread then = "in that case" rather than "at that time". Agreed, people as far West as South Germany can look a bit Oriental.
Well it seems to me that just as we don't regard all descendants of King William (Conqueror) as being royal, so too the descendants of Jesus+Mary would have a ranking. I imagine that our C20 femme is the first born female. Sort of a female Primogeniture (is there a word?).
Then too is the issue that people tend to marry within their caste. Thus I suspect the 2^N calculations are invalidated by the fact that as time goes by the chance of marrying a co-descendant must increase somewhat, particularly if the pool of potential partners is small. {Insert joke here about shortage of children with parent who talks to god} In short there must be a lot of double counting in the calculation after a few generations.
"After all, the natural laws of mathematics surely cannot operate in a universe where it takes a detective and a trained cryptographer at least five pages to spot that a text is written backwards."
Well, they were French... ;)
"Give me 'The Day of the Triffids' anytime!"
For which, if I'm not mistaken, there's another remake on the cards?
Is it not well known that we are all descended from Mahomet?
Given how many wives he had - and how young some of them were - it seems only too likely.
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