The Comet ISON, said to be the "comet of the century," is visiting the sun for Thanksgiving Day and there's still one last chance to catch it this week before it fizzles or makes history. The large space snowball's existential journey to the sun can either annihilate the comet or make it into a luminous and majestic celestial body for a short period of time.

Comet ISON is basically a rock covered with tons of snow and ice from deep space. It has been flying its way past planet Earth and neighboring planets in the last few weeks on a sungrazing course with the nearest star. It will reach its perihelion point as it comes closest to the sun's surface within 730,000 miles only on Thanksgiving afternoon and whip around the sun's other side to head back to Earth's direction.

Many astronomers doubt the ISON will survive its closest encounter with the sun but if it does, it could be one of the brightest comets we'll see in recent decades and even longer if it passes its way out of the solar system in December.

It could also turn into millions of smithereens by the huge amounts of energy radiated by the sun and never be heard of again. Either way, it's good to have a comet ISON viewing plan now. If you haven't seen ISON yet, which has been visible with a good telescope or set of binoculars under the right conditions for a few weeks now, it's your chance to catch a glimpse of it before its solar encounter with the sun.

NASA says the comet's nucleus will be below the southeastern horizon, right of Mercury and Saturn and you would be able to spot its tail. There's a good chance the comet will break up before it can make a round trip so this could be your last chance to see the brilliant comet.

The ISON will make its final approach on the sun so unless you want to go blind staring directly to the sun, a better plan is gather the family around on Thanksgiving to watch "Fire vs. Ison" for live coverage of perihelion and ISON's potential breakup. The ISON will reach a top speed of around 845,000 mph.

Latest reports speculate that Comet ISON "probably has not survived its journey" as the comet became faint while within view of NASA's Solar Terrestrial Relations Observatory. Other reports say it is still very much intact, though.

If Comet ISON survives, it would reemerge from its shadow and start to be visible in December. The weeks before Christmas and New Year's Eve would show ISON at its brightest and could even be luminous enough in daylight skies.

By Christmas day, ISON would be visible above North America's nighttime sky horizon all night long before fading away in January. Take note though that all these are just educated guesswork as comets are unpredictable by nature.