Comet Ison "may have survived" sun's heat, say astronomers Maybe after a five-and-a-half million year journey, scientists were premature in writing off Comet Ison as dead, if not exactly buried, in a matter of hours. Astronomers now say that maybe its close brush with the sun was less suicidal than they initially thought - and some of it may have survived temperatures approaching a cool 3000 degrees Celsius. Something has re-emerged on the other side of the sun, and it has been brightening. Earlier Ison appeared to be disintegrating as it came within just over a million kilometres from the sun's surface. What's left could be just a cloud of dust that will soon disappear. Or it could be the comet's tail, which astronomers say may be visible from Earth just before dawn.