Today, in the journal Science, Australian scientist Keith Bannister announced findings that might help solve a 30-year old mystery. Bannister and his team used Gemini to provide baseline optical observations of a quasar (PKS 1939-315) which has displayed wild fluctuations in its radio emissions. The Gemini Director's Discretionary Time program, using the Gemini Multi-Object Spectrograph at the Gemini South telescope, confirmed that the optical light is constant, while the radio emission changes. The steady optical light, concurrent with the radio variations, means that earlier optical surveys for dark clouds would not have found these. Also, these lenses must not be dusty, because dust would have reddened the quasar's light. Read more