Comet ISON

Credit: HST

A comet’s journey through the solar system is perilous and violent. A giant ejection of solar material from the sun could rip its tail off. Before it reaches Mars -- at some 230 million miles away from the sun -- the radiation of the sun begins to boil its water, the first step toward breaking apart. And, if it survives all this, the intense radiation and pressure as it flies near the surface of the sun could destroy it altogether.
Right now, Comet ISON is making that journey. It began its trip from the Oort cloud region of our solar system and is now travelling toward the sun. The comet will reach its closest approach to the sun on Thanksgiving Day -- Nov. 28, 2013 -- skimming just 730,000 miles above the sun’s surface. If it comes around the sun without breaking up, the comet will be visible in the Northern Hemisphere with the naked eye, and from what we see now, ISON is predicted to be a particularly bright and beautiful comet.
font: NASA
More info: wikipedia