Halley's Comet May Be Linked to Famine 1,500 Years Ago | Space.com

"A piece of the famous Halley's comet likely slammed into Earth in A.D. 536, blasting so much dust into the atmosphere that the planet cooled considerably, a new study suggests. This dramatic climate shift is linked to drought and famine around the world, which may have made humanity more susceptible to "Justinian's plague" in A.D. 541-542 — the first recorded emergence of the Black Death in Europe."