A solar flare, a metal axe and a wooden stump walked into a radio carbon dating laboratory.

I loved this story in the Wall Street Journal about science guys precisely dating a Viking settlement on the North American continent to 1021. (It gave me ideas for an alternate history epic about a Viking Amerikka, but I put them aside like a good boy and went back to my current deadlines.)

They were able to pinpoint when the Viking’s were there because of massive solar flares known to have occurred in 993. The flares threw off a space tsunami of carbon 14, which was stored in the rings of billions of trees.

“Any tree growing in the world in 993 will have embedded this rich carbon level,” said Dr. Dee, who helped pioneer the use of the carbon-14 spikes for dating. “There will be this jump.”

Dr. Dee and his colleagues tested wood specimens that showed the distinctive cut marks left by a metal blade—an implement unknown among the indigenous people of the era, who used only stone tools. Using the carbon spike as a reference point, they counted the tree rings in each specimen until they reached the bark, indicating the year the tree was cut down—in this case 1021.

“We have three wooden artifacts from three different trees and they all give the same date, “ Dr. Dee said. “This is really a big change in the precision that is achievable with scientific dating.”

That’s pretty cool science, right there.