It’s not a major break, but it appears that the comet is starting to lose chunks from its nucleus.
Earlier this month, the potential “Comet of the Century” underwent a rapid brightening event, likely caused large fissures of ice suddenly sublimating and blasting gas into space. The resulting increase of gas contained within the comet’s coma and tail reflected more light from the sun, causing it to brighten and become a naked-eye object. Although ISON could be spotted for a few days just before dawn, its light is quickly becoming overwhelmed by sunlight as it approaches perihelion (solar close approach).