Is this a closeup look at a tree stump, or an orbital view of an impact crater? At first glance, it might be hard to tell. But this image of a crater on Mars provides planetary scientists almost the same kind of climate history data about the Red Planet as tree rings provide to climate scientists here on Earth.
The Sun has a lot of rhythm and goes through different cycles of activity. The most well-known cycle might be the Schwabe cycle, which has an 11-year cadence. But what about cycles with much longer time scales? How can scientists understand them?
As it turns out, the Sun has left some hidden clues in tree rings.