Can a powerful CME cause a comet to fragment?

[slang]

[...] I suspect you are exactly right: there is no distinction between asteroids and comets.

That's quite a bit stronger than Van Rijn said. Most comets probably are quite different from most asteroids. I think his point is, and no doubt he'll correct me if I'm wrong, that it is not a black and white issue, that there is a gray area. How loose must a body* be to still be called a comet? At what density would it be called an asteroid? If a type of rock usually only found in asteroids happens to be present in small amounts in a comet, will it suddenly be called an asteroid, despite tail, coma, nuclues 'n all? And those are probably not the only fuzzy areas in differences between asteroids and comets.

*) an astronomical body, get your mind out of the gutter! :)

[tusenfem]

A (I)CME is an (Interplanetary) Coronal Mass Ejection, the „I“ being put in by Chris Russell for IMHO no reason, just to discern whether the CME is still near the Sun or already departed into interplanetary space. A CME consists of a self-consistent cloud of magnetic field and plasma and is ejected at high velocity from the solar surface. They can be small but sometimes the “opening angle” can be as large as more than 100 degrees. Here is a paper discussing solar flares and CMEs and how they are related.. CMEs occur as single events, I don’t think that there have been cases of multiple CMEs at the same time.

Now a CME contains about 1E12 kg of mass and a magnetic field strength of about 20 nT and a velocity of say 450 km/s with a density of up to a few 1000 cm-3. These are mainly magnetic structures, because the solar corona plasma is so dilute. When such a CME comes into contact with the Earth’s magnetic field, then two things can happen: 1) it will have the same magnetic field direction as the Earth’s field and thus impact and compress the Earth’s field, creating some activity, and 2) it can have the opposite magnetic field direction and thus start magnetic reconnection at the nose of the magnetopause, opening up the field and the magnetosphere and creating lots of activity like geomagnetic storms and aurorae. In the Carrington case there must have been a case 2 because the aurora was seen at very low latitudes, indicating that a lot of the Earth’s field had been eroded away and deep penetration of the CME plasma was possible. The aurora then is showing up through the interaction of the fast electrons and ions with the neutral molecules of the atmosphere, green light from nitrogen and red light from oxygen. An overview of magnetic clouds near the Earth can be found in Lepping et al. (1990).

Now a cloud like this has a ram pressure ρv^2 ~ 0.2 nPa, let’s for fun compare this with a nice Dutch autumn wind force 7, which is about 15.5 m/s and at a density of 1.3 kg/m3, which leads to a ram pressure of 300 Pa, i.e. about 12 orders of magnitude higher than the CME in space. An interesting lesson, note that in space many quantities are measures in nano (=1e-9) units. So yes loose snow will get blown away at force 7, but a built snowman will not disintegrate by the wind.

But … CMEs are … plasma, is that not different? Well no, not exactly, a few more things can happen though. At the Earth there is nothing much more that described above, although there may be better descriptions, even by myself (for the case of not a CME but just the solar wind magnetic field rotating I did the following study (open access journal). But what happens with non-magnetized bodies like comets?

First of all the magnetic field of the solar wind will get draped and piled up around the nucleus when it gets active (usually at about 4.5 AU from the Sun). Here is a paper by Gortsas et al. (2010) who model the outgassing of the comet and the draping and piling up of the magnetic field around the nucleus for Rosetta’s target P69/Churyumov-Gerasimenko, based on observations of its previous tour around the Sun. The outgassing is solely a product of solar radiation heating up the surface and lower layers and letting volatiles build up until the pressure is enough so they can escape. Note that we are working in a vacuum here, which means that often the fluid phase is omitted and solids (ices) sublimate.

Now sometimes the comets flare up, as discussed in this thread, which has nothing to do with outgassing, but everything with stirring up dust. Velocity-waves were shown to interact with the comet’s nucleus and throwing up dust, increasing the albedo, making a flare-up. A CME will do the same, a sudden increase in ram pressure (solar wind ram pressure is about a factor 100 smaller than for the CME) and the surface dust, created through pulverizing impacts onto the surface of the comet, is stirred up. But then, what is the use of having a plasma if it does not do anything. Well, not anything is incorrect. The CME or solar wind plasma will interact with the surface of the comet and the gas that is sent out. Although most of e.g. the water leaving the comet will be photo ionized, it can also collide with a solar wing ion and charge exchange. Now this is an important mechanism for the X-rays that were discussed in this thread. But first can a CME break up a comet? I would say no, because there is just not enough oompf in a CME, sure it can wreak havoc in our magnetosphere, but that is mainly because of the magnetic reconnection happening, not because of its impact. If a comet can survive the sudden onset of the jets, when they “break their pockets” and shoot into interplanetary space, then it can certainly survive a CME bumplet.

Can the ions of the CME enter into the comet proper? The answer is most likely no, because at Earth’s orbit the piled up/induced magnetosphere around the comet is about 30 nT strong, that means that the CME will be braked by the comet and the ions cannot move in a direct line to the nucleus because of the protecting magnetic field around it. That does not mean not any plasma will hit the surface, but to “enter” the nucleus and break it up from the inside, no, the density of the CME is just too small to do anything significant. It will be interesting to see what the instruments on Philea will measure, the lander part of the Rosetta mission. I think that Harri Laakso [1991] gives a very good description of the full plasma environment around Comet Halley.

Now, the X-rays that were found at the comets, that were a bit of a mystery when first seen. However, after a few years of investigation as is described at the end of the link it was understood what was happening. It was not a very hot spot on a cold object, but the already mentioned charge exchange was playing an important role. It was found that the frequencies of the emitted X-rays agreed with e.g. highly ionized oxygen, O6+. These ions are created at the sun and come with the solar wind. When they collide with a neutral from coma they can take an electron from the neutral, generating a new ion and an excited O5+. The latter will fall back, emitting an X-ray photon. Here is a very recent paper by Bodewits et al. (2012) on the topic and how the X-rays and UV emissions can help investigate comets surroundings further. Will the X-rays heat the comet and let it break up? I doubt it, because this is all happening in a very large region and the total energy in these X-rays is in the end so little, that it will have negligible effect on the comet proper. You would have to send a beam of X-rays to the surface of the nucleus (not unlike the laser on Curiosity) in order to achieve something. However, we see the X-rays from various viewing directions, meaning that the emission process of them, as is well know, is random. And building an X-ray laser in a plasma (like a maser) has not yet been observed.
Naturally there are still things unknown about comets, and the Rosetta mission will solve some of these and probably find many more interesting and unknown things as it is the first mission to ever follow a comet along its orbit and put a lander on the surface.

Ain’t science great.

[tusenfem]

I suspect that just as the solar wind can heat the gases in the coma to temperatures hot enough to produce x-rays,

But that is NOT what is happening, do you actually read the stuff you link to? See the end of my essay CMEs, comets and Carrington.

[gdaniels99]

But that is NOT what is happening, do you actually read the stuff you link to? See the end of my essay CMEs, comets and Carrington.

Read? yes. Fully comprehend? Not so much. But I can always count on you to set me straight which is why I do so much enjoy our little interactions.

[gdaniels99]

Can the ions of the CME enter into the comet proper? The answer is most likely no, because at Earth’s orbit the piled up/induced magnetosphere around the comet is about 30 nT strong, that means that the CME will be braked by the comet and the ions cannot move in a direct line to the nucleus because of the protecting magnetic field around it. That does not mean not any plasma will hit the surface, but to “enter” the nucleus and break it up from the inside, no, the density of the CME is just too small to do anything significant.

"Most likely no" suggests there is some wiggle room here. How powerful would the CME need to be to have any chance of entering the nucleus (through fissures, cracks, etc..not necessarily through the solid surface) and having any effect?

I'm not looking for a run-of-the-mill CME. Not even Carrington Event level. Perhaps of a magnitude that would only occur every 5,000 years. The event I'm studying coincides with a Beryllium 10 spike in the Greenland Ice Core data. This suggests a highly active sun and/or a weakened/absent magnetic field.

So would a much stronger CME combined with a weaker magnetosphere create a perfect storm situation where something more catastrophic could happen inside the comet?

[tusenfem]

"Most likely no" suggests there is some wiggle room here. How powerful would the CME need to be to have any chance of entering the nucleus (through fissures, cracks, etc..not necessarily through the solid surface) and having any effect?

I'm not looking for a run-of-the-mill CME. Not even Carrington Event level. Perhaps of a magnitude that would only occur every 5,000 years. The event I'm studying coincides with a Beryllium 10 spike in the Greenland Ice Core data. This suggests a highly active sun and/or a weakened/absent magnetic field.

So would a much stronger CME combined with a weaker magnetosphere create a perfect storm situation where something more catastrophic could happen inside the comet?

You have no idea how few particles there are there in space. They cannot do anything, they cannot penetrate the nucleus. First they will be shielded off by the magnetic field then part of them will hit the nucleus. Penetrate maybe a few centimeters at most, they will not do anything to the comet, let alone break it up. This is just getting silly, you are just upping and upping and upping the anty like a small child that does not get his will, there is no way in space you will break up a comet with a CME, not with the shock, not with ram pressure, not with the charged particles.

[Tensor]

Go read my post #5 on this thread. I explain in detail why I am even interested in the CME-Comet Fragmentation idea. It has to do with comet fragments hitting earth.

Actually, most of post five is nothing more than speculation, without any kind of actual evidence* You try to connect hypotheses (not theories, you're using the word theorize incorrectly) from different people for different possible events. But, don't provide any kind of actual evidence other than, it seems, “Well, there’s nothing that says it can’t.” * **

And what are comet fragments called once they enter earth's atmosphere????? I'll let you think on that for a while and see if you can make the connection yourself.

Depends. Since meteor is defined as the visible path of a meteoroid, fragments can enter and leave the Earth's atmosphere without becoming a meteor. * Fragments can even hit the Earth without actually leaving a visible trail, which would make them meteorites. *Which one do you mean, the one that doesn't leave a trail and moves back out into space, or the one that hits the Earth, without leaving a trail? Or, are you going by the actual definition of meteor? You don’t really specify the conditions.*

Have you even bothered to actually read this entire thread????? Clearly you haven't. When Comet Holmes had an outburst when it was far away from any gravitational effects of Jupiter or the Sun, astronomers noted large fragments speeding AWAY from the comet at speeds up to 280mph.

Actually, I have, read it. But the problem is that you have obviously not even bothered to do some basic calculations, if you think 280 MPH is going to change the velocity vectors of fragments all that much.

Van Rijn noted that Holmes was moving over 20,000 MPH. At the point of the outburst(2.44 AU) I actually get just over 49,000 MPH. Fragments, blowing off at 280 MPH, orthogonally, will result in the fragments being a total of just over ~27000 miles, off the original travel path, over four days. Which means, for your example, the blowoff would have to happen within ~4.8 million miles AND the original path, of the comet, would have been closer to the Earth than the moon to get the fragments to the Earth in four days.


As far as backing off your claim that Holmes was only an example, that still doesn’t matter. That ~27,000 mile distance is for any comet blowing off fragments, at a right angle, moving at 280MPH for four days (280 x 24 x 4 = ~26,000). For the original path of the comet to even be as far away as the moon, the fragments would have to be blown off at ~2500 MPH, almost ten times the speed observed for Holmes. Not to mention that most comets would be moving faster at the point of the Earth’s orbit, so the fragmentation event would have to happen even closer than the ~4.8 million miles to the Earth. Do you really think that any comet that close to the Earth would have been missed?

If you want to stick with claiming that 280 MPH is enough to change velocity vectors in a major way, specify which comet, when, it’s location, and then provide us with the calculations showing that what you are claiming is possible.

And this outburst wasn't caused by a CME, just good ole charged particles from the solar wind. So could a CME cause greater effects?

No, see tusenfem’s post.

It represents ONE mainstream position. Put five astronomers in a room and you'll get five different positions.

It’s actually the mainstream position. Put several hundred astronomers in the room, and you’ll get a scientific consensus. There may be opponents to that consensus, but that doesn’t mean that the consensus isn’t the mainstream position. I didn’t see you provide any kind of support that the majority of astronomers have a different position. Are you planning on providing such support?

Besides, there are papers out there purporting to show that Special Relativity is wrong. Do you really think that is the mainstream position?

But funny how you completely ignored all the X-Ray evidence I posted. Care to take a shot at that?

As soon as you post some, I’ll be more than happy to look it over. What you did was to link to popular science articles. Most of which are written for dramatic effect, rather than straight science fact. What actual papers have you linked to concerning cometary x-rays?

Someone previously mentioned that charged particles would have no influence on a comet's gasses when I asked that question a day or so ago. Now it looks like they have a TREMENDOUS impact on those gases, heating them up to the point where they emit x-rays.

Again, what papers? What effect specifically are they talking about?

So just because someone on this forum says something is the mainstream position doesn't make it so.

And assertions with no support, other than “there’s nothing that says it can’t”, doesn’t make it so either.

It may mean they simply don't know about more recent research.

Science articles for the general public are not evidence nor are they actual research.
How about you provide some actual papers and some actual calculations since you’re the one claiming all this is possible? All you’ve done is trying to do science by incredulity.

I notice you didn’t even bother to show that there was an increase in meteor sightings after the Carrington event (other than the mention of the one meteor by two different sources in southern Australia).

Also, do you truly believe that one bright meteor, in one location, represents a significant meteor event? If so, I saw a significant meteor event in the 1970s, 1980s and within the last decade. And if you do believe it represents a significant event, other than their proximity to one another in time, what evidence do you have that they were related in some other way?

[Van Rijn]

Van Rijn noted that Holmes was moving over 20,000 MPH. At the point of the outburst(2.44 AU) I actually get just over 49,000 MPH.

I suspected my number was low, should have double checked it. Oh, well.

[gdaniels99]

This is just getting silly, you are just upping and upping and upping the anty like a small child that does not get his will,

No, I am exhausting all possibilities until none are left. So far you have successfully explained away all the possibilities and so until I get further evidence I'll have to go with your explanation.

But when I first started this thread I was told the odds of a comet taking a direct hit by a CME were very low and that this could not lead to a fragmentation. Then exactly a year later Comet Elenin took a direct hit from a CME and then fragmented. So I came back to this thread and posted this evidence to see if maybe there was a link. Again, after I exhausted all possibilities I let the mainstream answer stand: no, CMEs can't fragment a comet.

Should a researcher stop pursuing explanations for an eyewitnessed event even if the explanation may go against current physics? Well read the following story about how Cornell researchers were able to solve the mystery of noctilucent clouds during the Tunguska Event:

"Space Shuttle Science Shows How 1908 Tunguska Explosion Was Caused By A Comet"

Here's a quote from the article:

The scientists have attempted to answer how this water vapor traveled so far without scattering and diffusing, as conventional physics would predict. "There is a mean transport of this material for tens of thousands of kilometers in a very short time, and there is no model that predicts that," Kelley said. "It's totally new and unexpected physics."

So, should these researchers have simply given up trying to explain how noctilucent clouds appeared over Europe from the Tunguska Event in Siberia just because the current physics models said such a thing wasn't possible? Of course not. That's what science is...it's about finding explanations for observed events even if current models say such events aren't possible. The map is not the territory. The model of reality is not reality. Just because an equation says something is impossible doesn't make it so.

So far it appears that maybe it was a coincidence that Elenin fell apart at the same time it was hit by a CME. But if another comet gets hit by a CME and also explodes, then I will be right back on this thread posting this event and seeing if any new physics might explain it. So if that's being a child, then sure, I'll take that as a compliment because I don't think science has everything figured out yet. New discoveries are made all the time. Just look what has been learned about comets in the past 20 years!

[Tensor]

I suspected my number was low, should have double checked it. Oh, well.

Don't worry, I spent two hours trying to figure out why I was getting an obviously wrong answer (~450,000MPH). Turns out, the value I was using was in km, not meters,which made my denominator too small. Once I saw and corrected that, the answer just popped out.

Edit to correct: it made my denominator not small enough to offset when I multiplied by GM.

[Shaula]

So far it appears that maybe it was a coincidence that Elenin fell apart at the same time it was hit by a CME. But if another comet gets hit by a CME and also explodes, then I will be right back on this thread posting this event and seeing if any new physics might explain it. So if that's being a child, then sure, I'll take that as a compliment because I don't think science has everything figured out yet.

In order for it to be science I'd suggest you also look at all the comets that were involved in CMEs and did not fragment too. The danger of basing your ideas on statistical outliers is a big issue in what you have been advocating here. Humans are good at spotting patterns, poor at assessing their significance (in the statistical sense)

[tusenfem]

Then exactly a year later Comet Elenin took a direct hit from a CME and then fragmented. So I came back to this thread and posted this evidence to see if maybe there was a link. Again, after I exhausted all possibilities I let the mainstream answer stand: no, CMEs can't fragment a comet.

I still have to see one mainstream paper about Comet Elinin, the only thing I can find are some messages and a lot of woo-woo sites mentioning it.

[gdaniels99]

In order for it to be science I'd suggest you also look at all the comets that were involved in CMEs and did not fragment too.

So far there have only been two recorded incidents of a comet being hit by a CME. Comet Encke in 2007 had its tail ripped off by a CME. Comet Elenin in 2011 which fragmented after being hit by the CME. So there isn't a huge body of data to do a statistical analysis on.

I started this thread before the Comet Elenin event based on the Comet Encke event. I found an old eyewitness account of a comet having it's tail ripped off. This was then followed by "blood rain" (a term Greeks used for red auroras like those experience during the Carrington Event) and then an impact event and impact tsunami.

The whole reason I asked if a CME could fragment a comet was to see if there was any connection between the "tail disconnection event" and the "impact event." I was assured no way a comet could fragment from being hit by a CME. Then the comet Elenin event happened exactly one year to the day that I started this thread. So now I had what appeared to be an actual comet fragmenting due to a CME. So I asked the question again. Got the same response: No way can a comet be fragmented by a CME. So I moved on.

The eyewitness account I'm studying recorded the date this event occurred. The Greenland Ice Core shows both a Berylium10 spike and Ammonium spike in this exact year. Tsunami records show megatsunamis in four separate oceans in this same year.

Berylium 10 is associated with major influx of cosmic ray particles. This can be due to increased solar activity or a decrease in the magnetic field letting more cosmic rays hit the upper atmosphere. Ammonium spikes are known signatures of impact events. Tsunamis are known results of oceanic impact events. Thus the eyewitness account is backed up by physical data. The physical data supports a very active sun and an impact event.

The question is, are they related? So far, it seems the event could have been like the Comet Elenin event....two events happening simultaneously that weren't necessarily connected but from an eyewitness watching the event, would have seemed connected.

I'm almost done with the first draft of the paper I'm writing on this eyewitness account and will post a link to it when I'm done so everyone here can "have at it."

[quotation]

So I just finished reading the following:

Interplanetary magnetic field rotations followed from L1 to the ground:
the response of the Earth’s magnetosphere as seen by multi-spacecraft and ground-based observations

It's very cool that so many devices, both space-based and ground-based were able to coordinate their efforts to come up with a coherent picture of what's "usually" going on. When I say usually, I'm assuming that the period measured is (more or less) what we expect to see on an "average" day. I also assume that the picture might be quite different during a CME event, although not as radically different as some might assume, and hope to see that too someday (as well as more detail on the additional structures alluded to). Thanks for taking the time and keeping us straight...btw is "green slinky" a technical term?

[iantresman]

So far there have only been two recorded incidents of a comet being hit by a CME.

As far as I know, the first recorded CME was in the 1970s, and the term was not used until that decade. So maybe association was not made before then, because the vocabulary and technology was not around before then.

[Reality Check]

Comets may simply be asteroids with gas jets.

This is not what the Wikipedia article or mainstream says.
It is physically impossible for comets to be "asteroids with gas jets" because comets have measured densities (~0.6 g/cc) that are much less than that of asteroids (~3.0 g/cc) (a JREF post about this to debunk the EC fantasy about comets).

There is an exception - the main-belt comets that have been detected are in fact low density asteroids with gas jets!

The Stardust surprise was that the Wild 2 dust showed signs of being formed in the inner solar system which then migrated outward to where comets formed. The only association with asteroids is that asteroids also formed in the inner solar system and so share properties with the dust. AFAIK there was an existing theory that dust particles would be driven from the inner to outer solar system by strong solar winds emitted by a young Sun. This is now part of the mainstream position on comet formation.

[Reality Check]

Hmmm....I see nothing but comet photos. no cats at all. but one insect ( a dragonfly).

See page 2 for the cat photo. Now list all of the photos in this Google image search which are of Temple1.

[Reality Check]

When Comet Holmes had an outburst when it was far away from any gravitational effects of Jupiter or the Sun, astronomers noted large fragments speeding AWAY from the comet at speeds up to 280mph. And this outburst wasn't caused by a CME, just good ole charged particles from the solar wind. So could a CME cause greater effects?

It looks like you have not bothered to read this thread !
Otherwise you would not speculate that that Comet Holme outburst was "good ole charged particles from the solar wind" when the mainstream position is

The cause of the outburst is not definitely known. The huge cloud of gas and dust may have resulted from a collision with a meteoroid, or, more probably, from a build-up of gas inside the comet's nucleus which eventually broke through the surface.[14] However, researchers at the Max Planck Institute suggest in a paper published in Astronomy and Astrophysics that the brightening can be explained by a thick, air-tight dust cover and the effects of H2O sublimation, with the comet's porous structure providing more surface area for sublimation, up to one order of magnitude greater. Energy from the Sun – insolation – was stored in the dust cover and the nucleus within the months before the outburst.[15]

You keep on mentioning the velocities of the outburst fragments (280mph). What is surprising about fragments from an explosion travelling fast?

[Reality Check]

I was only using Comet Holmes to demonstrate that fragmentation events can happen far from the gravitational influences of the sun or Jupiter ....

That is the main problan with citing Comet Homes in this thread: it was not a fragmentation event!
It was an outburst. The nucleus of Comet Holmes is intact.

[Reality Check]

So far, it seems the event could have been like the Comet Elenin event....two events happening simultaneously that weren't necessarily connected but from an eyewitness watching the event, would have seemed connected.

This seems like you are using the Comet Elenin event as a correlation = causation argument. There are at least 3 problems with this argument.
Firstly you can never get correlation from a single event. You need multiple events.
Secondly tusenfem has pointed out that there is no causation - CME cannot cause fragmentation.
Thirdly there is a much better causation - tidal forces - with multiple events to provide correlation.

Comet Elenin was close to the Sun and probably running out of volatile materials. So the scenario of fragmentation from heating of volatile materials by a CME is very unlikely.
It is a lot more likely that this was just tidal forces.

[gdaniels99]

In post #133 above I mentioned what made me ask this question in the first place and that I would post a link to my research once it was completed. Here's that link:

[commercial link removed]

In a nutshell I found a Mayan "myth" which stated in 3300 BC a "cosmic crocodile" was decapitated which led to a "flood of blood" on Earth. This event happened 11 years after the appearance of a "god" in the sky. Since much mythology is really astronomy in disguise I was trying to understand the astronomical underpinnings of this myth. A cosmic crocodile seemed like a good metaphor for a comet: head & long body/tail. And the inclusion of "11 years" suggested to me the 11 year solar cycle. So my first question that I asked Google was "can a solar flare or CME decapitate a comet." Luckily for me the search results returned a link to a NASA video showing Comet Encke being decapitated by a CME:

http://apod.nasa.gov/apod/ap071003.html

OK, so a comet can be decapitated by a CME but how would that cause an impact? I thought the only way this could produce an impact was if the CME somehow caused the comet to fragment. So after my google searches failed I came here and asked that very question. Answer: nope. CME can't cause comet to fragment. After Comet Ellenin was hit by a CME and then fragmented I came back and asked again. Same answer: nope, CME can't fragment a comet.

OK fine. But that still left me with trying to understand this Mayan record of an impact event. And the impact event is real. As I discussed in post #133 there is an ammonium spike in the ice core record for 3300 BC which is a marker for impact events. There is sedimentary evidence (i.e. tsunami deposits) that multiple high energy tsunamis occurred in 3300 BC. And there is a Beryllium-10 spike in the ice core record that could either represent a supernova or very high solar activity. So the Mayan "myth" doesn't seem so mythical any more.

Then I found a piece of Mayan pottery which records this same event. It's called the Mayan Blowgunner Vase. You can see it here:

http://research.mayavase.com/kerrmay....php?vase=1226

According to Mayan scholars it shows a figure named Jun Ahau (One Lord/One Sun) using a blowgun to shoot a "celestial bird" from a "cosmic tree." At the base of that tree is a scorpion which has been interpreted as the constellation Scorpio. The celestial bird is depicted as a Quetzal bird, a brilliant green bird from southern mexico with very long tail feathers. A bird that flies across the sky with long tail feathers is a perfect symbol for a comet. Curiously, Jun Ahau-One Sun, is shown with spots on his body like the sun with sunspots. The hieroglyphs near the blowgun have been translated as "he descends from the sky." Thus you have a Solar figure shooting a blowgun at a celestial bird "comet" figure and causing it to descend from the sky. That sounds like the sun shooting a CME at a comet which causes it to somehow crash into Earth.

These are not the only such stories from around the world. In Hindu mythology we have the story of Rahu. Just like the cosmic crocodile in the Mayan myth, Rahu is decapitated. Rahu is the name of the head and Khetu is the name of the tail. Khetu also means "comet" so there's no doubt we are talking about a comet. The decapitation is said to have been caused by Vishnu (a sun god) who threw his Sudarshana chakra to accomplish the task. The Sudarshana chakra is described as "sun dust." That sounds like a perfect description of a CME. So once again we have the sun being directly implicated in the fragmentation of a comet.

The Chinese have the same exact "myth" called Taotie. The Greeks have Medusa. (Medusa's head was chopped off by Perseus using a sword created by the same deity who created the Sun's chariot that drove him across the sky. Thus the sword is clearly a part of the sun.) I discuss these myths here:

[commercial link removed]

So we have the same story in cultures all over the earth that a comet was beheaded, part of it struck earth causing a flood, and this beheading was said to have been caused by the sun.

If there was just one such story maybe it could be ignored. But when everyone on Earth tells the same story and one culture, the Maya, even recorded the date that this event occurred on and this date just so happens to match with ice core evidence that a comet impact event occurred during a period of heightened solar activity....well, you have to have an almost maniacal faith in coincidence to dismiss all of this as coincidence.

So, can a CME fragment a comet? The myths suggest yes, comet Elenin suggests yes. The standard physics model suggests no.

So, maybe people in 3300 BC witnessed an event that was a combination of the comet encke/comet elenin event. They saw a comet get hit by a CME, saw its tail ripped off (decapitated), and then saw the comet fragment. They would have connected these events regardless of the true physics. Or......maybe the standard physics model is wrong and needs a second look. It seems all the comments have been based on :normal: CMEs but I believe this event was likely the result of a CME or flare orders of magnitude larger than the Carrington Event. It's like asking can the wind blow down a building. If you're talking about everyday normal winds, no, of course not. If you're talking about a tornado....the scenario changes completely. But whichever the case may be, I think it is all pretty fascinating.

[Swift]

gdaniels99,

You are very rapidly crossing the line from asking a question to advocating a non-mainstream position. And it is doesn't matter if you can find a reference or two to support your position, it is a non-mainstream idea.

You want to ask IF a CME can cause a comet to fragment or ask about particular pieces of information, that's fine. But if you continue to argue when given the mainstream answers, this thread will be closed or moved to our Against The Mainstream (ATM) forum.

A reminder of my August warning. It still stands.

[tusenfem]

Decapitating and fragmenting are completely different things, I think. One is just the comet losing its tail, which happens through magnetic reconnection. The fragmenting is the actualy breaking up of the nucleus, which happens now and then near perihelion, and also happens during strong gravitational stress like comet Shoemaker-Levy before it fell into Jupiter.

Up to now there is no peer reviewed paper about Comet Elenin, the only source seems to be CBET and various websites, which is too bad, because it is an interesting case, seeing the short wiggling of the cometary tail as the blast passes by.
The website linked to this forum e.g.:

However, Musgrave added, each comet is unique. “Some comets will survive and some won’t. The fact that this comet decreased in brightness after the CME, possibly indicates that the comet will not survive. Another possibility is that merely the CME wiped away the coma — the bright cloud of particles around the comet — and the volatiles of the comet might take awhile to come back and recreate the coma, if it does survive.”

Read more: http://www.universetoday.com/88494/c...#ixzz2BzxJIBAG

So yes, we know that comet can break up when they get near perihelion, yes we know that Elenin was hit by a CME, no we do not have any evidence that the CME broke up the comet, it may have helped, but it was in the "break up region" anyway.

You will have to do much better than just quote whatever myth you think interesting and put your twist to the story.

[Van Rijn]

Decapitating and fragmenting are completely different things, I think. One is just the comet losing its tail, which happens through magnetic reconnection.

Is the disruption of a comet's tail actually referred to as "decapitation" in any scientific literature?

[tusenfem]

Is the disruption of a comet's tail actually referred to as "decapitation" in any scientific literature?

Not that I have seen, though it is a nice metaphor I guess in mythological kind of sense or the french revolution.

[Sp1ke]

Surely it should be decaudation rather than decapitation?

[Hornblower]

Surely it should be decaudation rather than decapitation?

I was thinking the same thing. Good catch!

[Van Rijn]

Surely it should be decaudation rather than decapitation?

Yes, exactly. For a decapitation, I'd expect that the head would be removed, not the tail. But the video at the APOD page gdaniels99 linked to shows Enke's tail (very thin gas and dust) behind the head being temporarily disrupted (you can see it reforming later in the video). The head remains intact throughout the video. The APOD page does not call it a "decapitation." Instead, this description appears to an invention by gdaniels99. Given what the video actually shows, "decapitation" is a misleading and inappropriate description.

[gdaniels99]

Decapitating and fragmenting are completely different things, I think. One is just the comet losing its tail, which happens through magnetic reconnection. The fragmenting is the actualy breaking up of the nucleus,

Yes, but they can also conceivably occur together. If a comet was hit by a CME near perihelion and experienced a tail detachment event nothing precludes that comet from also fragmenting due to the sun's gravity. I suspect this is what these old myths may refer to.

So yes, we know that comet can break up when they get near perihelion, yes we know that Elenin was hit by a CME, no we do not have any evidence that the CME broke up the comet, it may have helped, but it was in the "break up region" anyway.

And we know CME's can rip off a comet's tail. Since gravity is invisible, to an observer on earth the tail disconnection event and breakup would have seemed connected regardless of the true physics.

You will have to do much better than just quote whatever myth you think interesting and put your twist to the story.

I didn't quote whatever myth I found interesting. I quoted from myths which happened to have identical details from cultures all over the globe. Each myth described the event in the same way and as having the same cause. I didn't twist anything. I simply offered my interpretation. And then I backed up my interpretation with physical evidence. If you have a better explanation that explains these myths AND the physical evidence in the ice core and sedimentary record then by all means write it up and publish it.

[gdaniels99]

Yes, exactly. For a decapitation, I'd expect that the head would be removed, not the tail. But the video at the APOD page gdaniels99 linked to shows Enke's tail (very thin gas and dust) behind the head being temporarily disrupted (you can see it reforming later in the video). The head remains intact throughout the video. The APOD page does not call it a "decapitation." Instead, this description appears to an invention by gdaniels99. Given what the video actually shows, "decapitation" is a misleading and inappropriate description.

You guys are hilarious. Way to completely miss the point and focus on some completely irrelevant part of my argument. While you have your dictionaries out, go look up the word "pedant" and see if applies to any of you.

But the point is, these myths refer to a celestial being having its head separated from its body/tail. Call it a decapitation or a decaudation. WHATEVER. We can sit here all day and argue whether a decapitation is separating someone's head from their body...or their body from their head. It's a distinction without a difference.