# So There's a Comet Headed This Way? **URL:** \ **Category:** Factual Questions\ **Created:** [August 20, 2013, 6:09pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730 "2013-08-20T18:09:53Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [August 22, 2013, 10:22pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/21 "2013-08-22T22:22:41Z")
As an aside, why is it so difficult to estimate a comet’s brightness? What variables are fuzzy? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 22, 2013, 10:58pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/22 "2013-08-22T22:58:13Z")
The comet itself is, literally. We can pin down the orbit pretty precisely, once we’ve observed it for a month or two, but it’s harder to determine the mass, and even if you know that, it’s almost impossible to know how much it will outgas. The gas cloud of a comet (or coma) can be bigger than the Earth… Or it can be almost nonexistent. ---
**Author:** ![outlierrn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/outlierrn/32/3005_2.png) [@outlierrn](https://boards.straightdope.com/u/outlierrn)\ **Post date:** [August 23, 2013, 1:59am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/23 "2013-08-23T01:59:50Z")
Hot Fudge Sundae\* (Lucifers Hammer reference) How much is nuts, how much is whipped cream, how much will boil away, how much light will it reflect. Those are questions they’ll be able to answer after it passes. ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [August 23, 2013, 2:35am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/24 "2013-08-23T02:35:52Z")
> [@MonkeyMensch](#): > > My guess is that ISON will break up before aphelion, shortly after passing the Roche limit, and then get its butt roasted, sice the surface to mass ratio will greatly increase after break up. But, given that aphelion passage (around Thanksgiving for the Yanks) will be just marginally visible due to its proximity to the Sun maybe there’ll be something to see. Don’t you mean perihelion? ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [August 23, 2013, 5:52pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/25 "2013-08-23T17:52:00Z")
> [@Johanna](#): > > Don’t you mean perihelion? I certainly do; nice catch. It’s funny as you proofread a post for spelling and grammar little things like word meaning can slip through the sieve. ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [August 23, 2013, 10:28pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/26 "2013-08-23T22:28:43Z")
> [@MonkeyMensch](#): > > I certainly do; nice catch. It’s funny as you proofread a post for spelling and grammar little things like word meaning can slip through the sieve. 'S OK. Aphelion your pain. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [August 26, 2013, 9:13pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/27 "2013-08-26T21:13:43Z")
> [@MonkeyMensch](#): > > I certainly do; nice catch. It’s funny as you proofread a post for spelling and grammar little things like word meaning can slip through the sieve. Spelling checkers have a long ways to go, eh? What self-respecting spelling checker of 2020 would miss that glaring error? > [@Johanna](#): > > 'S OK. Aphelion your pain. And spelling checkers don’t detect bad puns. Yet, so watch out. 🙂 ---
**Author:** ![Knorf](https://avatars.discourse-cdn.com/v4/letter/k/58956e/32.png) [@Knorf](https://boards.straightdope.com/u/Knorf)\ **Post date:** [November 29, 2013, 5:34am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/28 "2013-11-29T05:34:39Z")
Sadly, it looks like comet C/2012 S1 (known as Comet ISON) has broken up [at or close to perihelion](http://www.usatoday.com/story/news/nation/2013/11/28/comet-ison-nasa/3776419/). Bummer. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [November 29, 2013, 12:44pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/29 "2013-11-29T12:44:54Z")
> [@Knorf](#): > > Sadly, it looks like comet C/2012 S1 (known as Comet ISON) has broken up [at or close to perihelion](http://www.usatoday.com/story/news/nation/2013/11/28/comet-ison-nasa/3776419/). Bummer. Or [perhaps it didn’t](http://news.sky.com/story/1174976/comet-ison-may-have-survived-brush-with-sun). ---
**Author:** ![Gyrate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gyrate/32/3588_2.png) [@Gyrate](https://boards.straightdope.com/u/Gyrate)\ **Post date:** [November 29, 2013, 12:46pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/30 "2013-11-29T12:46:49Z")
As always, [there’s an xkcd for that](http://xkcd.com/1297/). ---
**Author:** ![Knorf](https://avatars.discourse-cdn.com/v4/letter/k/58956e/32.png) [@Knorf](https://boards.straightdope.com/u/Knorf)\ **Post date:** [November 29, 2013, 11:44pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/31 "2013-11-29T23:44:35Z")
Indeed! It knows appears that the comet is [not quite dead](http://www.youtube.com/watch?v=qdnAfrMFQkc), yet. Tentative “woo-hoo.” ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [November 30, 2013, 12:41am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/32 "2013-11-30T00:41:08Z")
> [@Spectre\_of\_Pithecanthropus](#): > > I saw Hale-Bopp from a beach west of Malibu; which is still considerably light polluted if not nearly as bad as most of L.A. County. It was a bit diffuse and faint, perhaps about as prominent as a first magnitude star allowing for the comet’s more diffuse structure. But there was no mistaking it, and it was spectacular enough that I was able to see it without deliberately looking for it. Spectacular? To me it looked like a fuzzy star. We havent had many really spectacular comets in living memory: > **[Great January Comet of 1910](https://en.wikipedia.org/wiki/Great_Daylight_Comet_of_1910)** > > The Great January Comet of 1910, formally designated C/1910 A1 and often referred to as the Daylight Comet, was a comet which appeared in January 1910. It was already visible to the naked eye when it was first noticed, and many people independently "discovered" the comet. At its brightest, it outshone the planet Venus, and was possibly the brightest comet of the 20th century. > The comet came to solar conjunction about 1 degree from the Sun on 17 December 1909 but was still about 1 AU from the Sun... > **[Great Comet of 1843](https://en.wikipedia.org/wiki/Great_Comet_of_1843)** > > The Great Comet of 1843, formally designated C/1843 D1 and 1843 I, was a long-period comet which became very bright in March 1843 (it is also known as the Great March Comet). It was discovered on February 5, 1843, and rapidly brightened to become a great comet. It was a member of the Kreutz Sungrazers, a family of comets resulting from the breakup of a parent comet (X/1106 C1) into multiple fragments in about 1106. These comets pass extremely close to the surface of the Sun—within a few solar rad... > **[Great Comet of 1744](https://en.wikipedia.org/wiki/C/1743_X1)** > > The Great Comet of 1744, whose official designation is C/1743 X1, and which is also known as Comet de Chéseaux or Comet Klinkenberg-Chéseaux, was a spectacular comet that was observed during 1743 and 1744. It was discovered independently in late November 1743 by Jan de Munck, in the second week of December by Dirk Klinkenberg, and, four days later, by Jean-Philippe de Chéseaux. It became visible with the naked eye for several months in 1744 and displayed dramatic and unusual effects in the sky. I... > **[Great Comet of 1882](https://en.wikipedia.org/wiki/Great_Comet_of_1882)** > > The Great Comet of 1882, formally designated as C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882. It was a member of the Kreutz Sungrazers, a family of comets which pass within 1 R☉ of the Sun's photosphere at perihelion. > The comet was bright enough to be visible next to the Sun in the daytime sky at its perihelion. The comet made its closest approach to Earth on 16 September 1882 at 0.99 AU and then came to perihelion (closest approach to the Sun) the next d... But the one I personally remember was [Comet Ikeya–Seki - Wikipedia](http://en.wikipedia.org/wiki/Comet_Ikeya%E2%80%93Seki) Visible in the daytime, but rather close to the sun. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [November 30, 2013, 9:00pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/33 "2013-11-30T21:00:26Z")
> [@DrDeth](#): > > We havent had many really spectacular comets in living memory [Comet West](http://en.wikipedia.org/wiki/Comet_West) in 1976 was quite beautiful. I saw it in the early morning light with a very long classic comet tail. All the other comets I’ve seen were just fuzzballs by comparison. The press coverage was basically nil due to the overhype of Kohoutek the previous year. West, like quite a few other comets, was also visible in the daytime. This really isn’t that rare. You just need to know where to look. [Phil Plait](http://blogs.discovermagazine.com/badastronomy/2007/01/14/comet-mcnaught-daytime-comet/), for example, saw McNaught with binoculars at noon. Hardly a great comet. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [November 30, 2013, 9:11pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/34 "2013-11-30T21:11:39Z")
> [@Johanna](#): > > 'S OK. Aphelion your pain. I syzygy did there. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [December 1, 2013, 12:17am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/35 "2013-12-01T00:17:21Z")
> [@Knorf](#): > > Indeed! It knows appears that the comet is [not quite dead](http://www.youtube.com/watch?v=qdnAfrMFQkc), yet. I would like to salute Karl Battams, astrophysicist at the Naval Research Laboratory, for clarifying the state of the comet in the New York Times. “It’s definitely maybe alive,” Battams said. “There’s a strong definite chance it might be, may be alive.” Thanks, Karl! There’s a big future for you working in the White House press office. _First there is a comet then there is no comet then there is_ ---
**Author:** ![Knorf](https://avatars.discourse-cdn.com/v4/letter/k/58956e/32.png) [@Knorf](https://boards.straightdope.com/u/Knorf)\ **Post date:** [December 3, 2013, 3:40pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/36 "2013-12-03T15:40:40Z")
Nope. Looks like its [nearly dead after all](http://www.nytimes.com/2013/12/02/us/comet-thought-dead-but-found-alive-is-now-fading-away-astronomers-say.html?ref=science&_r=0). Quite the drama, though. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [December 3, 2013, 10:11pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/37 "2013-12-03T22:11:01Z")
As one of the commenters on the CBC site said: Comet ISON. Comet IsOff, Isn’tOn, WasOn, NowOff. Comet MightBeBackOn ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [December 11, 2013, 5:44am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/38 "2013-12-11T05:44:37Z")
> [@DrDeth](#): > > Spectacular? To me it looked like a fuzzy star. We havent had many really spectacular comets in living memory: > > [Great January Comet of 1910 - Wikipedia](http://en.wikipedia.org/wiki/Great_Daylight_Comet_of_1910) > [Great Comet of 1843 - Wikipedia](http://en.wikipedia.org/wiki/Great_Comet_of_1843) > [Great Comet of 1744 - Wikipedia](http://en.wikipedia.org/wiki/C/1743_X1) > [Great Comet of 1882 - Wikipedia](http://en.wikipedia.org/wiki/Great_Comet_of_1882) > But the one I personally remember was [Comet Ikeya–Seki - Wikipedia](http://en.wikipedia.org/wiki/Comet_Ikeya%E2%80%93Seki) > > Visible in the daytime, but rather close to the sun. So it wasn’t visible in daylight; but it was still sufficiently bright and well defined that I could easily make out the object and its classic “comet” shape. I say it was real, and it was spectacular! 😃 ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [December 11, 2013, 6:13am UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/39 "2013-12-11T06:13:50Z")
[Looks like it’s officially dead.](http://www.usatoday.com/story/news/nation/2013/12/10/comet-ison/3897623/) ---
**Author:** ![fiddlesticks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiddlesticks/32/18129_2.png) [@fiddlesticks](https://boards.straightdope.com/u/fiddlesticks)\ **Post date:** [December 11, 2013, 4:23pm UTC](https://boards.straightdope.com/t/so-theres-a-comet-headed-this-way/666730/40 "2013-12-11T16:23:21Z")
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