The stone slab is marked with round divots arranged in a circle, and an astronomical analysis suggests that these markings coincide with heavenly events, including sunrises and moonrises.
     Last year, study researcher Larisa Vodolazhskaya of the Archaeo-astronomical Research Center at Southern Federal University in Russia and her colleagues analysed a different Bronze Age sundial found in Ukraine, and discovered it to be a sophisticated instrument for measuring the hours. Their work came to the attention of archaeologists in Rostov, Russia, who knew of a similar-looking artefact found in that area in 1991, which had been sitting in a museum and never thoroughly studied.
     The Rostov slab was found over the grave of a man who had died about age 50, and dates back to the 12th century BCE - similar in age to the one found in Ukraine.
     By studying the geometry of the Rostov slab, Vodolazhskaya and her colleagues discovered that the carved circles, which are arranged in a pattern about 33 centimetres in diameter, correspond with the sunrises at equinoxes and solstices.
     The Bronze Age people who created this pattern weren't only interested in the sun. The circles that didn't correspond to solar movements were linked to lunar wanderings. The angle of the moon's orbit goes through an 18.6-year cycle, during which its position shifts. The Rostov slab tracks these movements with circular carvings indicating the southernmost and northernmost moonrises of these 'low' and 'high' moons.
     The slab was found at a Bronze Age Srubna or Srubnaya site, a culture which flourished on the steppes between the Ural Mountains and Ukraine's Dneiper River. The artefact, Vodolazhskaya says, may be the work of Bronze Age scientists.

Edited from Discovery News (16 October 2014)