>>>>>>>http://www.theregister.co.uk/2013/11/28/comet_ison_breaks_up/
>>>>>>
>>>>>>New here this morning says that U.S. astonomers believe something has emerged - maybe only a smaller fragment.
>>>>>
>>>>>I guess, quite literally, we will see ...
>>>>
>>>>Not without binoculars (or a telescope) ;-{
>>>
>>>And clear skies - never a given in my area this time of the year.
>>>
>>>It looks like reports of its death MAY have been premature:
>>>
>>>http://www.nasa.gov/content/goddard/comet-ison-may-have-survived/
>>
>>Odd how it appears to be larger coming out - but with no obvious tail away from the sun.
>
>One interesting thing about this is ISON was a first time comet. Never seen before, first detected Sept 2012. So presumably if one was ever earth bound (a very remote possibility) thats about how much notice we would get. Certainly not enough time to do anything about it.

According to the Wiki article ( http://en.wikipedia.org/wiki/C/2012_S1 ) it has/had a high orbital inclination of 62.4 degrees, way off the ecliptic. Most of the interesting (and potentially threatening) action in the solar system is in the plane of the ecliptic. Even that narrow slice is arguably not that well covered. If you want to monitor the entire sphere, that's a lot of space. It's amazing these things get discovered at all, for comets probably only because they develop a highly visible coma. Bare rocks with typically low albedos, we'd never see those.

JPL thinks anything left after perihelion is on a hyperbolic/ejection trajectory, so we'll never see it again.