The weak illumination of the dark side of Venus known as the Ashen Light represents one of the oldest unsolved mysteries in the observational history of the solar system, having first been reported in 1643 by the Jesuit professor of astronomy at Bologna, Giovanni Battista Riccioli. Widely thought to be an observational artefact, the phenomenon is elusive and erratic in appearance, but the evidence as it is currently formed is too ambiguous, too circumstantial, and much too contradictory to furnish a satisfactory rationale.
Journal of the British Astronomical Association
- Pub Date:
- December 2000