Scientists from the American Geophysical Union studied tree rings and reconstructed the history of solar activity from them.
Solar activity is constantly occurring on the star closest to the Earth. For example, strong magnetic storms can affect the operation of electrical appliances, as well as the condition of people. However, there has previously been no way of knowing how often and how intense such storms have occurred in the past.
The authors of the new work explain that solar energy particles (SEP), entering the atmosphere, cause a chain reaction that leads to the formation of a carbon-14 atom. This atom accumulates in wood, and fluctuations in its level indicate the activity of SEP exposure in a particular year.
Therefore, the researchers analyzed wood harvested in three regions:
- bristly pine in California,
- Scottish pine in Finland,
European larch in Switzerland.
Mass spectrometry samples were sent to determine the carbon-14 content.
As a result, the authors found out that 5411 BC. e. and 5410 BC. e. a very powerful storm probably occurred: atmospheric carbon-14 increased by 0.6% in the Northern Hemisphere and persisted for several years. There were also strong storms in 660 BC. B.C., 774-775 A.D. e. and 992-993 A.D. e.
The authors continue to study historical solar activity in order to expand our knowledge of it and predict the future behavior of the Sun.