In 1492, Columbus sailed the ocean blue. But…

In 1021, the Vikings landed in Newfoundland.

That’s right, we’re now certain that Norse explorers reached North America nearly 500 years before the Spaniards.

It happened at L’Anse aux Meadows, in easternmost Canada, where explorers in the 1960s discovered the remains of Viking longhouses. But they didn’t know exactly when they arrived or left.

We now know they were here exactly in 1021.

That’s because a team of scientists has figured out how to tie tree rings to solar storms.

Different texts, from isolated countries around the world, describe red auroras in the sky in the year 993—a telltale sign of a solar storm, when radiation bombards our atmosphere.

The radiation produces higher levels of carbon-14, which is absorbed by plants.

The researchers studied wood scraps from trees cut at L’Anse aux Meadows, probably to build its Viking architecture. When they found correspondingly high levels of carbon-14 in a tree ring, it pegged that ring to the year 993. They could then count outward to the bark to identify the year the tree died.

All trees showed marks from iron tools, which no native tribes had at the time. And all were felled a thousand years ago, in 1021.