Hopes rise for 'dead' Comet Ison
29 November 2013 Last updated at 10:29 GMT
Comet Ison, or some part of it, may have survived its encounter with the Sun, according to scientists.
The giant ball of ice and dust was initially declared dead when it failed to re-emerge from behind the star with the expected brightness.
But recent pictures have indicated a brightening of what may be a small fragment of the comet.
The BBC's Pallab Ghosh reports.