Una cometa non periodica potrebbe diventare una delle più luminose degli ultimi anni nei cieli dell’emisfero boreale.
È la ISON, scoperta nell’autunno 2012. Il 28 novembre transiterà vicino al Sole e dovrebbe essere visibile a occhio nudo inizialmente all’alba e poi alla sera fino alla fine dell’anno.
ISON suscita aspettative negli astrofili che potrebbero però essere deluse: il passaggio della cometa di Halley, nel 1986, fu molto meno appariscente, smentendo le previsioni, rispetto a quello del 1910. L'ultima "grande cometa" fu la Hale-Bopp, apparsa nel 1997.
(DPA/mas)
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