Comet Halley Dust Clouds"

A false-color image of the enormous hydrogen cloud surrounding Comet Halley, created with data from University of Colorado-Boulder's ultraviolet spectrometer on the Pioneer Venus Orbiter. The image covers an area 20x23 million kilometers, and the Sun in the lower left corner is to scale. The image was generated by researchers from the University of Colorado, NASA-Ames Research Center, and the University of California-Davis.