The linear extension on the right is scientifically reliable, based on measurements of the rate of revolution of Sirius B around Sirius A. The linear extension on the left is not scientifically reliable. It is a presumed correlation, for there is no way in which the rate of revolution of Digitaria can be known certainly from the Dogon information. These linear extensions cannot, therefore, be considered to constitute hard evidence of a correlation. It is likely, though, that they do correlate because Digitaria is presumed to move at a rate which makes astronomical sense (for if the shape of the orbit and the distance match, the period should match)

From The Sirius Mystery by Robert Temple