Did a meteor over central Italy in AD 312 change the course of Roman and Christian history? A team of geologists believes it has found the incoming space rock's impact crater, and dating suggests its formation coincided with the celestial vision said to have converted a future Roman emperor to Christianity.It was just before a decisive battle for control of Rome and the empire that Constantine saw a blazing light cross the sky and attributed his subsequent victory to divine help from a Christian God.
Constantine went on to consolidate his grip on power and ordered that persecution of Christians cease and their religion receive official status. < snip >
It is the small, circular Cratere del Sirente in central Italy. It is clearly an impact crater, Ormo says, because its shape fits and it is also surrounded by numerous smaller, secondary craters, gouged out by ejected debris, as expected from impact models.
Radiocarbon dating puts the crater's formation at about the right time to have been witnessed by Constantine and there are magnetic anomalies detected around the secondary craters - possibly due to magnetic fragments from the meteorite.
According to Ormo, it would have struck the Earth with the force of a small nuclear bomb, perhaps a kiloton in yield. It would have looked like a nuclear blast, with a mushroom cloud and shockwaves.