A gamma-ray burst may have caused an intense blast of high-energy
radiation that hit the Earth in the eighth century, report
scientists from the Astrophysics Institute of the University of
In 2012, scientist Fusa Miyake announced the detection of high
levels of the isotope Carbon-14 and Beryllium-10 in tree rings
formed in 775 CE, suggesting that a burst of radiation struck the
Earth in the year 774 or 775.
Carbon-14 and Beryllium-10 form when radiation from space collides
with nitrogen atoms, which then decay to these heavier forms of
carbon and beryllium, the journal Monthly Notices of the Royal
Astronomical Society reports.
The earlier research ruled out the nearby explosion of a massive
star (a supernova) as nothing was recorded in observations at the
time and no remnant has been found, according to an Astrophysics
But Valeri Hambaryan and Ralph Neuhuser, of the Astrophysics
Institute, have another explanation, consistent with both the
carbon-14 measurements and the absence of any recorded events in
They believe the gamma ray burst originated in a system between
3,000 and 12,000 light years from the Sun.
They suggest that two compact stellar remnants, i.e. black holes,
neutron stars or white dwarfs, collided and merged together.
When this happens, some energy is released in the form of gamma
rays, the most energetic part of the electromagnetic spectrum that
includes visible light.