Variation of the constellations over time. Graph showing the variation in the positions in the sky of six southern hemisphere constellations over time. The limits of the latitude from which they can be seen (down left) has been plotted against 5000 years of history (along bottom). Our epoch (2000 AD) is at far right. This evidence indicates that these six southern contellations were created sometime in the first millennium BC (where the lines converge). Since that time, as the Earth's position relative to the stars has changed, the constellations have drifted apart, leaving a southern void without any constellations. Schaefer (2002) concluded that these constellations were Babylonian in origin.