A new study suggests the disk was made to accurately represent the brightest stars at least 2,400 years ago, possibly as an aid for planting crops. But other experts are not convinced.

A roughly 3,000-year-old stone disk covered with enigmatic markings is actually an ancient celestial map marking the brightest stars in the night sky, researchers claim.

The tire-size stone, which was discovered near an ancient hill fort in northeastern Italy a few years ago, features 29 carved markings on its front and back that may represent the brightest stars in the night sky, researchers posit in a new study, published on Nov. 22 in the journal Astronomical Notes.

However, astronomer Ed Krupp, the director of the Griffith Observatory in Los Angeles, who was not involved in the stone’s discovery, told Live Science he thinks any relationship between the carved markings on the stone and the brightest stars may be accidental.