Astronomers have several hypotheses about what could have caused this phenomenon. However, a full study of these events makes their cause even more mysterious.
High-energy particles collide with nitrogen atoms in the upper atmosphere to produce radioactive carbon-14, the longest-lived radioactive carbon isotope that enters the planetary carbon cycle and is taken up by plants.
This means that rings of ancient trees will help scientists discover what caused the abundance of carbon-14 in the distant past.
Ten years ago, scientists found explanations for the small changes in carbon-14 over the past thousand years, but a huge spike in 774 AD immediately puzzled them....<<<Read More>>>......