writes "Last year, astronomers announced that a small ball of ice and rock heading towards the inner Solar System could turn out to be the most eye-catching comet in living memory. They calculated that Comet Ison's orbit would take it behind the Sun but that it would then head towards Earth where it would put on a spectacular display of heavenly fireworks. Sure enough, Ison brightened dramatically as it headed Sunwards. But as astronomers watched on the evening of 28 November, the brightly flaring Ison moved behind the Sun but never emerged. The comet simply disappeared. Now a new analysis of the death of Ison suggests that the comet was doomed long before it reached the Sun. Images from several Sun-observing spacecraft that had a unique view of events, indicate that Ison exhausted its supply of water and other ice in the final flare-ups as it approached the Sun. The new study shows that all that was left in its last hours were a few hundred thousands pebbles glowing brightly as they vapourised in the Sun's heat. In fact, Comet Ison died in full view of the watching hordes of astronomers on Earth who did not realise what they were watching at the time."