ocr: Left top panel: Comets ore consumables'. For insfance, spacecratt observations showed that Halley's comet lost 20-40 metric tons of mass per second in the form of gas and dust. Middle panel: The comet's tai emerges ata distance ofapproxi mately3 AU from the Sun. At its longest the fail can be many fimes longer than the distance be wween the Earth and - the Moon. Right bottom panel: The cometary nucleus has - a diamefer of some kilometres and rotates slowly.
