Only a small bit of the sun-grazing Comet ISON has apparently survived its perihelion passage on Thanksgiving Day (November 28th), so no grand display of a comet with a tail visible to the naked eye will be seen. Still, the comet has given a lot of scientific data through spectra from ground-based telescopes and views from a variety of spacecraft. (See Section 8.3)
Comet ISON, which has orbited the Sun among the objects of the Oort cloud for almost 4.5 billion years, perhaps as much as a light-year away from the inner Solar System, has remained largely untouched since the time of the Solar System’s formation. Since it was first detected nearly a year ago, astronomers hoped that its passage would offer a unique glimpse of the state of our Solar System in its earliest moments.