2013 Comet to be a “once in a civilization” event?

A reader alerted me to this from Scientific American:

Next year’s “brightest comet in modern times” to be “once in a civilization” event

As it flares out of the distant Oort Cloud, the newly discovered comet C/2012 S1 (ISON) appears to be heading on a trajectory that could make for one of the most spectacular night-sky events in living memory. Why is this comet expected to be so unique? Two reasons:

Astronomers predict that the comet will pass just 1.16 million miles from the Sun as it swings around its perihelion, or closest approach. (This may seem like a lot, but remember – the Sun is big. If we were to scale the Sun down to the size of Earth, the comet would pass well within the orbits of dozens of satellites.) The close approach will melt enormous amounts of the comet’s ice, releasing dust and gas and forming what should be a magnificent tail.

After it loops around the Sun and forms this tail, the comet should then pass relatively close to Earth – not near enough to cause any worry, but close enough to put on a great show. Viewers in the Northern Hemisphere will get the best view as the comet blooms in the weeks approaching Christmas 2013. The comet could grow as bright as the full moon.

Of course, comets have a habit of not living up to expectations. This one could be sucked into the Sun during its close approach, or not grow as much of a tail as astronomers hope.

But that hasn’t dampened enthusiasm for what Astronomy Now is awkwardly calling “a once-in-a-civilisation’s-lifetime” event.
The comet expert John E. Bortle is already comparing ISON with the Great Comet of 1680, which, according to contemporary accounts, caused the people of New York’s Manhattan Island to be “overcome with terror at a sight in the heavens such as has seldom greeted human eyes…. In the province of New York a day of fasting and humiliation was appointed, in order that the wrath of God might be assuaged.”  [We could use a little more of that, frankly.]


The piece goes on to quote another author:

The Dutch and Quaker Colonies in America by John Fiske

Chapter XI, ‘New York in the Year 1680’

Late in the autumn of 1680 the good people of Manhattan were overcome with terror at a sight in the heavens such as has seldom greeted human eyes. An enormous comet, perhaps the most magnificent one on record, suddenly made its appearance. At first it was tailless and dim, like a nebulous cloud, but at the end of a week the tail began to show itself and in a second week had attained a length of 30 degrees; in the third week it extended to 70 degrees, while the whole mass was growing brighter. After five weeks it seemed to be absorbed into the intense glare of the sun, but in four days more it reappeared like a blazing sun itself in the throes of some giant convulsion and threw out a tail in the opposite direction as far as the whole distance between the sun and the earth. Sir Isaac Newton, who was then at work upon the mighty problems soon to be published to the world in his Principia, welcomed this strange visitor as affording him a beautiful instance for testing the truth of his new theory of gravitation. But most people throughout the civilized world, the learned as well as the multitude, feared that the end of all things was at hand. Every church in Europe, from the grandest cathedral to the humblest chapel, resounded with supplications, and in the province of New York a day of fasting and humiliation was appointed,in order that the wrath of God might be assuaged.  [Like I said, above, we could use more of that all the time and not just in moments of crisis.]

About Fr. John Zuhlsdorf

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  1. Thom says:

    I really don’t understand why Scientific American seems not to be aware that every close examination of comets by spacecraft has shown little or no ice. They are rocky bodies like asteroids. See for yourself: https://www.youtube.com/watch?v=wn_HqbMmn-4

  2. Banjo pickin girl says:

    I can’t get utube but I know from spectroscopic studies that the composition of comets is complex, containing rock, frozen water, and other frozen gases such as methane and ammonia. That is what causes the tail. If they were all or mostly rock the tails would not form as they do neither would they have the spectral characteristics that they show.

  3. wolskerj says:

    Whenever I read these extravagant predictions I can’t help thinking “Kohoutek, Kohoutek, Kohoutek . . . .” I hope I’m wrong.

  4. majuscule says:

    When I was a child my grandfather told me of seeing Halley’s Comet filling the early morning sky as he went out to bring in the cows for milking. I think it really impressed him because, at that time, he was newly in love with his future wife–my grandmother.

    I figured I would be an old lady by the time I saw it when it came around again. Well, I wasn’t so old and it didn’t put on its show.

    I’m not holding my breath for this one. But it would sure be nice if it were bigger than Hale-Bopp.

  5. Laura R. says:

    Given the “light pollution” in modern cities, would those of us in such cities be able to see it very well? The skies in 1680 must have looked very different —

  6. Suburbanbanshee says:

    Ammonia, etc. also form ice. Or at least, they form solids which are colloquially called “ice.” That’s what a lot of comet-melt is made of.

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