When they get near the sun , they warm up and spew some of the gas and dirt , creating tails that can stretch for thousands of miles . Comet ISON -- or at least part of it -- may have survived , experts say . Comment: The fate of the comet remains uncertain . It was making its closest approach to sun .
Comet ISON -- or at least part of it -- may have survived , experts say . Comment: The fate of the comet remains uncertain . It was making its closest approach to sun .