WASHINGTON -While today’s stargazers eagerly anticipate comets, ancient cultures often branded them as ‘harbingers of doom’. Now a US study suggests that people living 1,500 years ago may have had good reason for fearing these celestial objects.

Scientists claim they can link Halley’s comet to a devastating famine that occurred in 536 AD.

The comet, they say, caused a change in climate when it hit, throwing up enough dust into the atmosphere to cause the planet to cool significantly. This led to a period of widespread drought, crop failures and famine. Scientists believe the event made humanity more susceptible to ‘Justinian’s plague’ in 541-542 AD, which is the first recorded appearance of the Black Death in Europe.

According to an analysis of Greenland ice that was laid down between 533 and 540 AD, large amounts of atmospheric dust fell on Earth at this time. ‘I have all this extra-terrestrial stuff in my ice core,’ study leader Dallas Abbott, of Columbia University’s Lamont-Doherty Earth Observatory told Live Science. Researchers believe the dust came from the Eta Aquarid meteor shower which is created by leftovers of Halley’s comet.

This may have caused a period of mild cooling in 533AD, but it cannot explain the global dimming event of 536-537, during which the planet may have cooled by as much as 3 °C (5.4 degrees Fahrenheit). Professor Abbot claims that one explanation is that something large hit the ocean. She claims to have found circumstantial evidence to support this theory.

The Greenland ice cores, she said, contain fossils of tiny tropical marine organisms. An extra-terrestrial impact, such as from Halley’s comet, could have blasted these low-latitude organisms to Greenland. In August, researchers at Harvard University said that a cosmic impact 12,900 years ago could have led to the demise of the ‘Clovis’ people of North America. A layer of platinum from an ice core taken in Greenland was dated back to the time of a known abrupt climate transition, known as the ‘Big Freeze’. According to researchers at Harvard University, this provides evidence that a comet tipped the world into its colder phase, making dozens of species extinct.