NASA released a lovely composite image of comet lulin. on january 28th, the swift gamma-ray satellite captured comet lulin with ultraviolet and optical light (blue and green), and x-rays (red).
there's a big cloud of atomic gas around the comet. when streams of particles from the sun, called solar wind, react with the comets extended gas, they emit x-ray light! as far as i know, this is the first view of a comet with such a range of wavelengths!