In terms of advancements in astronomy, the Sumerians made star catalogues and used a 12-month solar calendar along with a 354-day lunar calendar. By the 3 rd millennium BCE, they regularly used a 360-day calendar. Evidence found in the underground library of King Ashurbanipal in Nineveh has puzzled experts, since it may indicate that the Sumerians observed the impact of an asteroid over 5,000 years ago.
