Here’s a really interesting story from Science magazine on a new way to date rocks. By looking at fossilized lightning strikes in rocks (called fulgurites) and measuring their amount of moisture, scientists can produce amazingly accurate dates of when the lightning hit. When lightning strikes the rock, it drives out all moisture, and the moisture gradually comes back over time in a predictable way, allowing very precise dating of when the rock was hit by the lightning. This is a brand-new technique that shows promise for providing information on weather of the ancient past. You can read more here.
