Halley's comet. Optical image of Halley's comet against a starfield,viewed on 12 March 1986. The comet consists of a potato-shaped nucleus of ice and dust. Its tail,stretching here more than 3 degrees from the nucleus,is formed as the comet is heated when it approaches our Sun. Dust and gas are swept into a tail both by solar radiation and by the solar wind. Named after Edmund Halley (1656-1742) who first realised its periodicity,the comet has been recorded every 76 years since 240 BC. Photographed by the UK Schmidt telescope,Australia | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Royal Observatory, Edinburgh |
Taille de l’image : | 3733 px × 2539 px |
Model Release : | Non requis |
Property Release : | Non requis |
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