Week of Dec. 1-7, 2013

Well, it's finally here! The week we've been anticipating for many months, when the great Comet ISON bursts into view and becomes the long-awaited Comet of the Century.

Or not.

It was in September of 2012 that Russian sky watchers Vitali Nevski and Artyom Novichonok discovered Comet ISON from the International Scientific Optical Network (aka ISON, for which it was named). After astronomers gathered enough data to calculate its orbit, they realized that ISON was going to swing within only one diameter of the blazing sun on Nov. 28 of this year and produce what could become a spectacular comet in our skies.

A comet is one of billions of tiny icy remnants of the primordial solar system that tumble silently through the vacuum of space. Occasionally, one of these cosmic nomads drifts inward toward the sun's heat, and its ices disintegrate into a cloud of gas and dust around its nucleus (the coma). Sunlight and the solar wind act as a fan and blow this material outward to create one or two tails that always point away from our star.

As compact as a comet may appear to us from our perch on planet Earth, it is actually spread out over many tens of millions of miles; in fact, to achieve the density of the air we breath, a comet's entire tail would need to be compressed to fit into the size of an average suitcase. In other words, a comet is the closest thing to nothing that's still something!

Now, calculating how a comet will move along its orbit and how close it will pass to the sun is relatively easy. That's just Kepler's laws of planetary motion. Trying to figure out how it will appear in our sky, however ... well, that's another matter altogether.

I mean, take a glacier-sized chunk of water ice and whip it at 240 miles per second to within less than one solar diameter of our 10,000-degree cosmic nuclear furnace and you tell me what will happen! Complicating matters even further is that a comet like this has never before been watched through this phase of its orbit, so your guess as to what will happen is as good as mine.

Yes, it's quite true, as noted comet-hunter David Levy likes to say, "Comets are like cats. They both have tails and they do precisely what they want!"

So what will happen to ISON after it rounds the sun? Well, it could vaporize completely, leaving only a wispy dust cloud to come out the other side; it could break up into several pieces, perhaps producing a few small comets in its place. Or ... and this is what we're all hoping for ... it could emerge its fiery journey as a spectacle the likes of which we haven't seen for years. As I write these words just before Thanksgiving, we just don't know.

About all I can with absolute certainty, however, is this: If you don't head out this week at dawn and look, you will definitely miss the sky show.

Whatever that turns out to be!

To keep up with the latest about Comet ISON, visit www.isoncampaign.org/Present

Visit Dennis Mammana at www.dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.