"An ancient disaster from the sky baffles historians"

Every day, an estimated 25 million pieces of space debris enter our planet’s atmosphere. Fortunately, most of these are small, even microscopic, and burn up before they reach the ground.

Scientists calculate, though, that each day an extraterrestrial object at least 40 centimeters in diameter might make it to the Earth’s surface. A meteorite at least ten times that size hits the Earth in any given year, and something even larger comes our way every century or so—as residents of Qingyang county in today’s Gansu province discovered one fateful evening in 1490.

The Veritable Records of the Ming, the official chronicle of the dynasty, noted that “stones fell like rain” in Qingyang county in the spring of 1490. Contemporary local records suggest as many as 10,000 people were killed by the falling rocks. The official history described some rocks as big as a goose egg and others as small as a chestnut, although it doesn’t mention any casualties. Modern researchers have questioned the enormous death toll, but the event certainly spooked the residents of Qingyang, and most of the survivors fled the area to resettle elsewhere.

The lack of corroborating data or physical evidence from 1490 makes it difficult to confirm if the cause of the devastation was an impact event from outer space or a freakish phenomenon from Earth. Some scholars have suggested the damage could have been caused by abnormally large and intense hail. But similar incidents from the annals of Chinese history suggest that a meteor might indeed be to blame.

In 616 CE, a “shooting star” may have landed in the camp of the rebel Lu Mingyue. Ten of Lu’s troops were killed when the meteor collapsed a siege tower. Records from Yunnan province in the early 14th century tell of an “iron rain” that destroyed crops and damaged homes across several counties.

Unexplained disturbances from above could be almost as worrying for China’s rulers as it was for people in the affected area. Almost every imperial capital had an observatory, which tracked the movement of heavenly objects in the sky, updated the calendars, and kept an eye out for anything which might be a portent that Heaven was displeased with their emperor’s rule.

Researchers have also compared accounts from Qingyang with more recent—and better documented—impact events. In 1908, a meteorite exploded a few kilometers above the Earth in Eastern Siberia. The Tunguska Blast flattened trees and devastated a fortunately unpopulated area about 40 kilometers in diameter. A 1994 paper by Kevin Yau, Paul Weissman, and Donald Yeomans from the Jet Propulsion Laboratory at CalTech suggested that a “somewhat larger stony meteorite exploding over a populated area” might explain reports like the one from Qingyang county in 1490.

Events as massive as the Tunguska Blast or the Qingyang Incident are rare in the annals of history, but they are a sobering reminder of what can happen as the Earth makes its way through a busy solar system.

“When Stars Attack”is a story from our issue, “Disaster Warning”. To read the entire issue, become a subscriber and receive the full magazine. Alternatively, you can purchase the digital version from the iTunes Store.