Astrochronology is making the science of reading tree rings more reliable than ever before.

While traditional carbon dating of tree rings is only vaguely accurate, experts are saying that Miyake events—colossal discharges of energetic solar particles—may be able to glean exact dates of ancient world events by acting as markers within the existing timeline of dendrochronology.

So far, scientists have discovered in trees two solar storms that manifest as rings with dramatically increased levels of C-14, an isotope of carbon. The first, found in 2012, dates back to 775 AD—the second, to 994 AD.

Here’s Tim Radford, reporting for The Guardian: