An artifact recovered in 2014 from the wreck of one of Vasco da Gama’s exploring ships, the Esmerelda, which sank in the Indian Ocean 1503, was believed to be an astrolabe, a navigation tool used to measure the inclination of celestial objects, but the 17.5-cm bronze disc appeared to lack any navigational markings. Scanning and 3D imaging the object at the University of Warwick revealed etches separated by five degrees along the edge, confirming that it was, in fact, an astrolabe. It’s dated to between 1495 and 1500, roughly, which makes it the oldest known astrolabe still in existence. BBC News. [Tony Campbell]