Chapter 52, Day 88: An Unnatural History of Homo Sapiens
“I guess I should start from the beginning,” Pryce said, looking up at the four dragons. “No one knows for sure, but humans have existed for at least 50,000 years.”
«Wait, I am confused,» Devotion said after Fathom echoed Pryce’s statement. «A clan of humans must have counted the years, but then why are they uncertain about that?»
Fathom translated this question, then added, “Dragons usually teach hatchlings about events that have happened in the last 1,000 years, anything older than that would be a special event, like a very strong earthquake or eruption.”
“Makes sense,” Pryce nodded. “And the others can’t understand how we determined that value yet, but I’ve taught you enough for you to understand, ready?”
Fathom nodded, eyes rapt with attention.
“Most of the nitrogen in the air is called nitrogen-14, because we add up the 7 protons and 7 neutrons to get 14 – there’s 7 electrons too, but those aren’t counted because they’re very light. The important part is that the energy of the sunlight turns a bit of the nitrogen-14 into carbon-14, which has 6 protons, 8 neutrons, and 6 electrons. This carbon-14 will float around and be absorbed by all living things until they die.”
[Nitrogen14 => Carbon14 diagram]