小橋 昭彦 2004年11月24日

The sun is more active now than over the last 8000 years
The scientists have analyzed the radioactive isotopes in trees that lived thousands of years ago. As the scientists from Germany, Finland, and Switzerland report in the current issue of the science journal “Nature” from October 28, one needs to go back over 8,000 years in order to find a time when the Sun was, on average, as active as in the last 60 years.