Scientists found that the level of carbon-14, an isotope of carbon, was much higher in rings from that year than usual. Some years later, looking at air samples from ice cores, scientists saw that there were elevated levels of beryllium-10 and chlorine-36 as well. The common factor in all these elements is that they are created when extremely high-energy subatomic particles hit Earth's air and ground. .... The only way to get particles at energies like this is from space, where powerful magnetic fields in exploding stars...can accelerate the particles to such high speeds. But the 774 event was so...