Unexpected Comet Pojmanski Now Visible . ... Comets bright enough to be visible to the unaided eye appear only every few years . ... Comet Pojmanski , officially designated C/2006 A1 and discovered only in January, now sports a turquoise tail several times longer than the full moon. Comet Pojmanski 's ion tail is due to gas particles expelled by the comet being pushed away from the Sun by the solar wind , the same wind that ionizes gas in the tail causing its blue tint. ...