ELI5: Explain Like I'm 5

Identical ancestors point

Do you know how your parents have parents and their parents have parents too? Well, their parents also had parents, and those parents had parents as well. This goes back a looong time, like hundreds and thousands of years ago.

Now, think about all the people who lived back then. There were millions and millions of them, right? But not all of them had kids who had kids who had kids and so on until today. Some of them didn't have kids at all, and some of them had kids but those kids didn't have kids, and so on.

So, let's say your great-great-great-great-great-grandparents had 5 kids, and each of those kids also had 5 kids, and so on until you were born. That means you had 2 to the power of 6 (or 64) great-great-great-great-great-grandparents.

Now, remember how not all those millions of people had descendants who are alive today? That means some of your great-great-great-great-great-grandparents were the same person!

The Identical Ancestors Point is the point in time in the past where all of our ancestors who are alive today are the same person. So if we go back far enough, say 2,000 years ago, we would find that all of us alive today have the same set of ancestors. It's like finding out we're all cousins many times over!

So, even though we come from different parts of the world, look different, and have different cultures, we all share a common ancestor at some point in the past. It's a bit like a huge family tree where we're all connected to the same person, just on different branches.