Apparent inconsistencies in our scientific understanding of comets

[JeanTate]

Thanks Sol88.

Thanks Sol88.

sorry, copy and paste not working nicely.

In order to model the outgassing of a comet at a rate of n[moleculess1],a spherical expansion is assumed where the gas moves away from the nucleus at a velocity of e[m/s].The neutrals gas,escaping from the comet will get ionized by solarUV radiation and/or collisions with the solarwind at a rate of[s1].Using this,the radial dependence of the neutral gas density n can be formulated by the Haser[1957]model: A Tail Like No Other

Is this still how mainstream work out the "outgassing" rate?

What is the source? What do you mean by "mainstream"? Why do you think this is (or may be) an inconsistency?

Remember, this is a thread devoted to scientific understanding. So please, always, provide a source.

A Tail Like No Other Martin Volwerk1, Charlotte Goetz2, Ingo Richter2, Magda Delva1, Katharina Ostaszewski2, Konrad Schwingenschuh1 and Karl-Heinz Glassmeier2

Give it a go!

Sorry, I have no idea what you mean.

Could you please clarify?

mainstream, YOU, have overestimated Q. Which led you to believe comets MUST be mostly ice.

First, you have presented zero evidence that I, Jean Tate, "have overestimated Q". If you have any, please present it.

Second, if your source points to an inconsistency in estimates of "Q", you have not pointed it out. Please do so.

Third: "[w]hich led you to believe comets MUST be mostly ice." This is obvious nonsense, if only because what I, Jean Tate, believe (or don't believe) is irrelevant here (we're having a scientific discussion, remember?). And you have presented no evidence, of any kind.

I'm sure you'd be the first to agree that this post thus fits the definition of spam rather well, right?

 

[abaddon]

what say ye abaddon, Rock or Dust?

Asked and answered. It's a false dichotomy.

 

[Mojo]

Hi Mojo, perhaps since your new here what does a bone fide, real mainstream, principle investigator of the deep impact mission mean when he said....



Do you think he meant dust or rock?

Depends on how you define your terms. You could start by defining “dust”.

 

[Reality Check]

Why assume spherical expansion?

Like I said bugger all water coming from a comet. ...

An ignorant question and usual blatant lies from Sol88. No inconsistencies in our scientific understanding of comets in this post !

The Haser model assumes spherical expansion to be able to model comets ! It is a model written in 1957 and so no access to supercomputers to do complex modeling of complex shaped coma. The situation is probably different today.

We see lots of water at comets, e.g. 5 million tones from Deep Impact !

Obvious lies about The Nucleus of Comet 67P/ChuryumovGerasimenko - Part I: The Global View – nucleus mass, mass loss, porosity and implications. It does not say no water from 67P. Its "very little" ices are inside the nucleus and at least 14% ices!

A lie that there is no mainstream explanation for the complex molecules at comets. Existing ices sublimating (water methane, carbon dioxide) + sunlight = complex molecules. That is mainstream chemistry at comets.

 

[Reality Check]

Now I just have to point out the inconsistencies and mainstream can sort it out.

Then why have your posts not done that Sol88?

Repeating years old, persistent lies about mainstream cometary science from another thread is not Apparent inconsistencies in our scientific understanding of comets.

 

[Reality Check]

Mainstream can’t even define the difference between a comet and asteroid.

Another lie from Sol88. No inconsistencies in our scientific understanding of comets in this post yet again !

Asteroid–comet continuum objects in the solar system is mostly about the few asteroids that sometimes have comet-like features.
A dense rocky object that never has a coma or tails is an asteroid.
A porous, ice and dust object that periodically has a coma and tails is a comet.

There are a few dense rocky objects that eject dust to form an dust cloud around them (comets have an gas and dust coma) and dust tail (comets have an ion tail and a dust tail).

Inactive and dormant comets had the potential in the 1970's to be confused with asteroids. Tests were established to remove that possibility.

A lie that M.A’Hearn wrote that comets are actual rock when M.A’Hearn used the standard practice of labeling consolidated dust as rock. M.A’Hearn wrote hundreds of papers on ices and dust comets.
Comets: looking ahead is a mainstream ices and dust comet paper.

A lie by quote mining Comets: looking ahead

(c) What are comets made of?
At the simplest level, a very basic question is whether comets are mostly ice or mostly rock/dirt/refractory material. Whipple’s [2] model of the dirty snowball, the first quantitative model, envisioned cometary nuclei as mostly ice, although our understanding has been evolving more toward mostly rock, particularly for 67P/C-G for which refractory/volatile ratios as high as 6 have been cited [3,4]. Nevertheless, there is still considerable uncertainty about even this basic parameter, not least of which is that most measurements are subject to selection effects in removing refractories from the nucleus to the coma, where they are observed as dust.

With improvements in remote sensing over the last decade and particularly the wealth of measurements from Rosetta, we are making large strides in answering the question of which volatiles (ices) are near the surface of cometary nuclei, and the Deep Impact experiment implies that the near-surface volatiles are representative of the deeper interior [5,6]. The indications are that there is a large dispersion in relative abundances with only very limited correlations between relative abundances and any other parameters. On the other hand, we know very little about the abundance of the many possible refractory species. As noted above, there were great advances from the Stardust mission, particularly the clear demonstration that cometary silicate grains had been transported from near the Sun to the region of cometary formation, but the selection effects in collecting the returned samples make it almost impossible to say much quantitatively about the bulk abundances of refractories [7].

(emphasized the lie by quote mining)
M.A’Hearn wrote that 67P is at least 17% ices (volatiles). The Deep Impact experiment shows that Tempel 1 is up to 50% water ices.

 

[Reality Check]

You tell me ‘O great and knowledgeable one, why is electrochemistry a NON starter?...

Another lie from Sol88. No inconsistencies in our scientific understanding of comets in this post yet again !

The post he replied to states why electrochemistry is a "non starter". What jonesdave116 does not mention is that Sol88's "electrochemistry" is not even science ! Sol88 believes in the ignorant electric universe fantasies of a electrochemist which he exposes on a crank website, in crank videos and at conferences full of cranks! He has had these fantasies since at least 2013 and not published a single scientific paper to turn them into science!

 

[Reality Check]

Do you think he meant dust or rock?

Another lie from Sol88. No inconsistencies in our scientific understanding of comets in this post yet again !

Michael O'Hearn is a now deceased mainstream ices and dust cometary scientist who has written hundreds of papers on ices and dust comets. When Michael O'Hearn writes "rock/dirt/refractory material" in a mainstream paper he means the dust part of ices and dust comets.

 

[abaddon]

Depends on how you define your terms. You could start by defining “dust”.

And that is important. If one is so inclined, one can define "rock" or "dust" however one likes according to some standard of when a rock somehow becomes dust at some arbitrary level of particle. Which changes depending upon mood.

What is a rational person to make of such rocket propelled goalposts?

Simple. I will believe in any crap as soon as evidence is provided. Absent evidence I have exactly no reason to believe whatever claim.

For some reason, cranks think their claim is sufficient. For something.

 

[Sol88]

And that is important. If one is so inclined, one can define "rock" or "dust" however one likes according to some standard of when a rock somehow becomes dust at some arbitrary level of particle. Which changes depending upon mood.

What is a rational person to make of such rocket propelled goalposts?

Simple. I will believe in any crap as soon as evidence is provided. Absent evidence I have exactly no reason to believe whatever claim.

For some reason, cranks think their claim is sufficient. For something.

M.A’Hearn is a crank?

although our understanding has been evolving more toward mostly rock

Not dust.


But we see dust.... what a crank this A’Hearn bloke is....

What on earth could be turning rock to dust? What if, just like asteroids, the rock is composed of hydrated minerals?

So there it stands comets are mostly rock or if you’d like to add stony agglomeration as per

the nucleus would be a highly porous stony agglomerate, essentially devoid of volitiles.

(rock) i’m Cool with that.

What comets appear NOT to have is enough ice.

Dust,rock,stone all the same? Ok then.

 

[jonesdave116]

M.A’Hearn is a crank?

Not dust.


But we see dust.... what a crank this A’Hearn bloke is....

What on earth could be turning rock to dust? What if, just like asteroids, the rock is composed of hydrated minerals?

So there it stands comets are mostly rock or if you’d like to add stony agglomeration as per (rock) i’m Cool with that.

What comets appear NOT to have is enough ice.

Dust,rock,stone all the same? Ok then.

And more ignorant gibberish. No rock. Never seen at a comet. Nothing is turning rock into dust. And hydrated minerals have nothing to do with anything. Do some science, or give up. You are extremely boring. Zero science, zero mechanisms. As usual. Have you ever even attended a science class beyond primary school?

 

[Reality Check]

M.A’Hearn is a crank? ...

Another lie from Sol88. No inconsistencies in our scientific understanding of comets in this post yet again !

It is Sol88 who has a years long obsession with insulting M. A’Hearn. No one who learns about real comets says comets are actual rock. M. A’Hearn wrote hundreds of papers on ices and dust comets. See The thousands of insane lies, delusions, insults, etc. since 6 July 2009 from Sol88 about his cult's electric comet and electric Sun dogma. Sol88 is obviously trying to derail a thread about our scientific understanding of comets into that cult's electric comet dogma.

 

[Reality Check]

What comets appear NOT to have is enough ice.

Another lie from Sol88. No inconsistencies in our scientific understanding of comets in this post yet again !

Sol88's unsupported fantasies about comets are not our scientific understanding of comets. Our understanding of comets is that they have varying amount of ices so that "enough" is his own fantasy. We have suspected that comets are not mostly ices for over 14 years as Sol88 has cited !

A lie by quote mining Comets: looking ahead. Michael A’Hearn wrote that 67P is at least 17% ices (volatiles). The Deep Impact experiment shows that Tempel 1 is up to 50% water ices.

 

[Sol88]

And that is important. If one is so inclined, one can define "rock" or "dust" however one likes according to some standard of when a rock somehow becomes dust at some arbitrary level of particle. Which changes depending upon mood.

What is a rational person to make of such rocket propelled goalposts?

Simple. I will believe in any crap as soon as evidence is provided. Absent evidence I have exactly no reason to believe whatever claim.

For some reason, cranks think their claim is sufficient. For something.

Further

Nevertheless, there is still considerable uncertainty about even this basic parameter, not least of which is that most measurements are subject to selection effects in removing refractories from the nucleus to the coma, where they are observed as dust.

Refractories, I hear you say.

Question is what’s removing the consolidated refractory material from the nucleus and turning into the observed dust?

Remember...

Conclusions. In the framework of the presented model, which can be considered common in terms of assumptions and physical parameters in the cometary community, the dust removal by a gas drag force is not a plausible physical mechanism. The sublimation of not only water ice, but also of super-volatile ice (i.e., CO) is unable to remove dust grains for illumination conditions corresponding to 1.3 AU. Away out of this impasse requires revision of the most common model assumption employed by the cometary community.

Is near-surface ice the driver of dust activity on 67P/Churyumov-Gerasimenko DOI: 10.1051/0004-6361/201630000

 

[jonesdave116]

Refractories, I hear you say

And? More word salad, and no science. Give up. Refractories is just shorthand for non-volatiles. Okay? Get it?

 

[jonesdave116]

Further to the previous;

Great balls of mire
Sykes, M. V. (1993)
https://www.nature.com/articles/362696b0

Analysis of the IRAS observations of eight trails indicates that short-period comets lose mass primarily in the form of refractory particles a few millimetres to centimetres in diameter. The average dust-to-gas mass ratio calculated is 3, the upper limit inferred from the Giotto observations of comet Halley (with a nominal value of 2). Assuming the same densities as above, this corresponds to a comet nucleus that is 75 per cent refractory debris by mass and 50 per cent by volume.

Which kills off Sol's favourite strawman. A mere 26 years ago.

Not that I've ever had to post this before!

http://www.internationalskeptics.com/forums/showpost.php?p=12683697&postcount=3508

 

[Reality Check]

...Refractories, I hear you say

Another lie from Sol88. No inconsistencies in our scientific understanding of comets in this post yet again !

Sol88 has been citing mainstream papers with "refractories" for many years. For example see A lie by quote mining Comets: looking ahead. Michael A’Hearn wrote that 67P is at least 17% ices (volatiles). The Deep Impact experiment shows that Tempel 1 is up to 50% water ices. Sol88 knows that this is the non-volatile component of ices and dust comets. The term "refractory material" also reflects the mainstream formation of dust grains in the hot conditions of the early Solar System.

 

[Sol88]

Further to the previous;

Great balls of mire
Sykes, M. V. (1993)
https://www.nature.com/articles/362696b0



Which kills off Sol's favourite strawman. A mere 26 years ago.

Not that I've ever had to post this before!

http://www.internationalskeptics.com/forums/showpost.php?p=12683697&postcount=3508

So Frozen mudballs then? Ok.

I don’t see how this nullifies A’Hearns statement or Patzold for that matter. The RSI never lies.

Thought we were up around 6:1 “Dust” to ice ratio?

Comets are mostly rock! Good find jd116.

 

[Mojo]

Thought we were up around 6:1 “Dust” to ice ratio?

Define “Dust”.

 

[jonesdave116]

So Frozen mudballs then? Ok.

I don’t see how this nullifies A’Hearns statement or Patzold for that matter. The RSI never lies.

Thought we were up around 6:1 “Dust” to ice ratio?

Comets are mostly rock! Good find jd116.

There is no rock. Stop lying. It is pathetic. It was merely to show that your claims that scientists still claim comets are mostly ice is just yet another of your deliberate lies. Lies are all you have. No science. No mechanisms. No evidence. Purely faith. In idiots.