Astronomy Picture of the Day . ... 28.09.1999 . ... The so-called mystery object appeared star-like but displayed colors unlike most stars or quasars . Further investigation has now revealed the object to be a Broad Absorption Line (BAL) quasar , a relatively rare type of active center of a distant galaxy. Different atoms and molecules in the absorbing gas surrounding the BAL quasar 's center probably cause the unusual colors. ... NASA Web Site Statements, Warnings, and Disclaimers . ...