Comet ISON is inching ever closer to thes sun, and it will get incredibly close later on today. In the meantime, you can watch its most recent progress in this video from NASA.
In the early hours of Nov. 27, 2013, Comet ISON entered the field of view of the European Space Agency/NASA Solar and Heliospheric Observatory. In this picture, called a coronagraph, the bright light of the sun itself is blocked so the structures around it are visible. The comet is seen in the lower right; a giant cloud of solar material, called a coronal mass ejection or CME, is seen billowing out under the sun.
It's not clear if the comet will survive its trip through our solar system -- but we'll find out later today. [NASA]