I was trying to get some idea of how many ancestors I had around the time of Socrates (399 BC is his death), so I tried coming up with a way to find it.(adsbygoogle = window.adsbygoogle || []).push({});

So I'll start at my birthday which is 1991. I'll pretend that my parents were both 30 when they had me; I'll also pretend every pair in history giving birth was 30 years old when giving birth.

I'll use intervals of 30 years going all way the way back to 399 BC from 1991, which is a 2390 year gap.

There are 79 intervals of thirty years that fit with in 2390 years gap.

So I came up with 2^79= 6.044*10^23

This can't be right?! This is basically Avogadro's number

I used 2^x to find the number of the ancestors at the time of 1781 (5 years after the declaration of independence) which at 7 generation was 128 people. And this seemed right.

I'm not adding the ancestors from previous intervals as I go along, each interval is just the number of people related to me at that particular time.

Am I doing anything wrong?

at birth...

# of present parents (1961)

2^1=2

# of grandparents (1931)

2^2=4

# of great grandparents (1901)

2^3=8...

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Hypothetical number of ancestors in 399 BC

**Physics Forums | Science Articles, Homework Help, Discussion**