Unexpectedly, these observations revealed weak silicate emission features from the comet, rather than the anticipated strong silicate features found in some prior Oort Cloud comet observations, including those of Comet Hale-Bopp and studies conducted with the Spitzer Space Telescope... This composition challenges existing theoretical models of how Oort cloud comets form.

It would seam as if nothing, no amount of observation or measurement will falsify the dirty snowball nonsense.

It would seam as if nothing, no amount of observation or measurement will falsify the dirty snowball nonsense.

That would be because they keep finding evidence in favour of it. Such as tonnes of ice floating around Hartley 2. 1OOO's of tonnes of it ejected from Tempel1 by an impact. Numerous observations of ice at 67P. When you see ice on the surface, subsurface and in the jets of comets, then it is a pretty safe bet that there is ice there. Not to mention all the gases in the coma, plus the density of comets.
Plus, nobody has ever come up with any other explanation that matches observation and measurement. And is the least bit scientifically literate.

It's obvious jonesdumb is blinded by his religious beliefs! Unexpected means "expected" and "challenges theoretical models" means confirmation! First we have Cap'n Stoopid, then da schnied being Major Stoopid, now we have General Stoopid, the Supreme Leader of the Stoopids in jonesdumb.

It's obvious jonesdumb is blinded by his religious beliefs! Unexpected means "expected" and "challenges theoretical models" means confirmation! First we have Cap'n Stoopid, then da schnied being Major Stoopid, now we have General Stoopid, the Supreme Leader of the Stoopids in jonesdumb.

Huh? How is this unexpected?

The bulk grain properties of comet C/2012 K1 (Pan-STARRS) are ***comparable*** to other NICs with weak 10 μm silicate features and ***similar*** in respect to coma grains seen in the small set of ecliptic-family comets (ECs) that have fragmented, explosively released subsurface materials, or have had materials excavated from depth.

Please explain. And then address the multiple ice detections I alluded to previously. You need to stop this Thornill-esque crap of relying on press releases, and read the papers. This one is free access. No excuse.

"The pristine nature of these comets"

"Comets originating from the Oort Cloud, like Comet C/2012 K1, remain unaffected by the thermal heating and radiation processing of the Sun."

Regarding our Sun, obviously that is true, but over geological timescales there have probably been thousands of close passes by other stars. It stands to reason that some of them must have passed close enough to render the Oort Cloud less than "pristine." This may also explain why we can't find "Planet 9" even though the data suggests it should be there.

Regarding our Sun, obviously that is true, but over geological timescales there have probably been thousands of close passes by other stars. It stands to reason that some of them must have passed close enough to render the Oort Cloud less than "pristine."

Unlikely, Mark. If they were close to another star, they would likely remain gravitationally bound to that star. The reason that these NICs (Nearly Isotropic comets) appear to be different is due to the lack of thermal processing.

Huh? How is this unexpected?

Ask the author of the article, I didn't write it. You should be directing your anger towards science journalists who seem to be out to lie about every thing they write about.

Huh? How is this unexpected?

Ask the author of the article, I didn't write it. You should be directing your anger towards science journalists who seem to be out to lie about every thing they write about.

Trying to criticise science based on press releases is pointless. Trying to do so when the paper is free access is just lazy. Press officers are unlikely to be conversant with the relevant science, and just have a read through the paper, looking for something 'sexy' or 'surprising' or 'unexpected', in order to make the work attractive to places like this.

"Unlikely, Mark. If they were close to another star, they would likely remain gravitationally bound to that star."

Considering a likely range of relative velocity differences between Oort Cloud objects (slow) and passing stars (very fast), perhaps the closest approaches would have been brief and only affected a small portion of the Oort Cloud, which was then scattered. There may be many comet-like objects our solar system has lost and many others that have been captured.

Looking at the geologically recent encounter of Scholz's Star with the Oort Cloud, one can only infer there were many close passes. If such a close passes only happened once every million years, then there have been roughly 4,500 of them since the solar system formed.

"Scholz's Star . . . is a dim binary stellar system about 17–23 light-years (away that) passed through the Solar System's Oort cloud (at 0.82 ly) roughly 70,000 years ago."

https://en.wikipe...z's_star

Doing a little thought experiment . . . if a close pass like Scholz's Star happened every say 4.5 million years, there would have been about 1,000 of them since the solar system formed. On the other hand, if they usually occur every 45,000 years, then we are talking about 100,000 close passes. If every 70,000 years is typical, then we are talking about 64,000 close passes.

My point is that a reasonable guess for the number of close passes is in the thousands or tens of thousands. It is like a highway out there with stars passing by all the time! The incredible number of close passes is clearly not being fully considered by anyone who labels the Oort Cloud as "pristine." If all this makes you a little uncomfortable, keep in mind that Alpha Centauri will only be the closest to our solar system for about 80,000 years or so, and that is on the long side.

https://en.wikipe...n_dwarfs

@Mark,
Sorry, I misinterpreted your initial post. I took it to mean that they had been hurtling around other stars, before ending up in the Oort cloud! Given the amount of woo on here....!
I have no doubt that passing stars occasionally disturb the Oort cloud. Hence why some of them end up in our neighbourhood. However, how close did those comets get to the star in question? What this paper is saying, is that an Oort cloud comet, entering the solar system for the first time, will not have undergone the same sort of thermal history and outgassing as comets which regularly come close to the Sun, such as Jupiter Family Comets, or other Oort cloud comets which have previously had a close encounter with the Sun, such as Hale -Bopp.
Admittedly, it is a very small sample size, but it tentatively looks as if there is an initial difference in the dust properties.
Interesting paper, if you haven't read it:
http://iopscience...181/meta

Amusing!

I have no doubt that passing stars occasionally disturb the Oort cloud.

But a stellar capture by a star such as our Sun is untenable by you, got it. What would prevent such an event?

"Given the amount of woo on here....! "

jonesdave, I could not agree with you more. It is like we are trying to calmly discuss some of the finer points comet formation and subsequent alteration while somebody else is screaming at the top of their lungs, "science journalists who seem to be out to lie about every thing they write about!"

To my point above, the paper here stated, "However, whether or not comet evolution, such as processing in the Galactic environment, can be ignored when comparing the Oort Cloud comet dust composition (including that expressed in fcryst) is an open question." I am inferring there is a good chance it should not be ignored, but of course, I don't have definitive proof either.

Amusing!

I have no doubt that passing stars occasionally disturb the Oort cloud.

But a stellar capture by a star such as our Sun is untenable by you, got it. What would prevent such an event?

Capture of what?

cd8, speculations and hypothesis are not proof or evidence. It will take a mind-boggling effort to categorize all the different possibilities for out-system comets.

And, then we'd have to do the same for passing star systems before we have any definitive answers to your questions. Please keep in mind, those answers your are demanding? Can honestly only be applied as factual for our star system and those systems that mingle with us. Those answers cannot be claimed as a 'Universal Truth'.

To add to your speculations... It appears possible, maybe probable that our Sun and at least one or two or more nearby stars approach on a regular basis.

If we discover a comet, with elemental isotopes not possible from our system? Could we be swapping cometary material back and forth on a regular basis?

Cause this subject is not confusing enough. Think of the befuddlement probable from trying to sort out this kludge-fest of cometary pik-up-sticks.

Hilarity abounding!

"science journalists who seem to be out to lie about every thing they write about!"

Can we get any more inane? It is in fact jonesdumb who is claiming the journalists lie about this and that. I merely read the article and made statements about that which I read. Contrary to jonesdumb's claims, the dirty snowball has been a failure on numerous aspects. Simply applying ad hoc adjustments is not the way science advancements are made, sometimes falsification requires a restart.

"science journalists who seem to be out to lie about every thing they write about!"

Can we get any more inane? It is in fact jonesdumb who is claiming the journalists lie about this and that. I merely read the article and made statements about that which I read. Contrary to jonesdumb's claims, the dirty snowball has been a failure on numerous aspects. Simply applying ad hoc adjustments is not the way science advancements are made, sometimes falsification requires a restart.

Lol. Nothing has been a failure, other than the electric comet woo. And that was dead years ago. Due to being scientifically impossible, as well as lacking a single piece of evidence in its favour.

Amusing!

I have no doubt that passing stars occasionally disturb the Oort cloud.

But a stellar capture by a star such as our Sun is untenable by you, got it. What would prevent such an event?

Capture of what?

Can you read? It's all there;
"But a ***stellar capture*** by a star ***such as*** our Sun..."

Due to being scientifically impossible,

So the photoelectric effect is "scientifically impossible" on comets? Photons cannot reach the surface of a comets? Silly!

Nothing has been a failure,

http://i.dailymail.co.uk/i/pix/2015/09/17/10/2C6A94F800000578-3238186-Comets_are_composed_of_frozen_gases_mixed_with_dust_giving_the_n-a-32_1442483569166.jpg

Nope, nothing at all. Expect the prediction of it appearance for one.

Nothing has been a failure,

http://i.dailymail.co.uk/i/pix/2015/09/17/10/2C6A94F800000578-3238186-Comets_are_composed_of_frozen_gases_mixed_with_dust_giving_the_n-a-32_1442483569166.jpg

Nope, nothing at all. Expect the prediction of it appearance for one.

Oh, wow. So, based on images from 1986, you 'predicted' the same for 2014? Brilliant! Guess what? We already knew it would be dark.

http://www.esa.in...e_up.jpg

Due to being scientifically impossible,

So the photoelectric effect is "scientifically impossible" on comets? Photons cannot reach the surface of a comets? Silly!

And what will that do? And in what quantities? Will it create ice? Nope.

Can you read? It's all there;
"But a ***stellar capture*** by a star ***such as*** our Sun..."

You're rambling. You're expecting the Sun to capture what? A comet? A planet? Another star?

Electric discharge clearly seen on comets.

https://youtu.be/zAbTTVxOhtU

Electric discharge clearly seen on comets.

https://youtu.be/zAbTTVxOhtU

LMFAO

@cd the pseudoscience cult acolyte
youtube? really?
right: because everyone knows that science is trumped when there is a youboob video!
just ask ken hamm!

1- this is a thunderdolts video
2- not one single scientific reference linked
3- thunderidiocy isn't science! it has no validation [ever], no evidence [other than looks like, so it must be.... or russels teapot], and no predictability, let alone falsifiability (every time it is falsified by observation or evidence you simply ignore the science that debunked your data and state we're all plasma idiots! LOL)

cult video dogma isn't the same thing as science

Electric discharge clearly seen on comets.

https://youtu.be/zAbTTVxOhtU

Yep, an electric discharge that was looked at by ALICE, which images in UV and FUV. It saw water ice grains. And guess what? Absolutely zilch to indicate an electrical discharge. More cold, invisible electric discharges! My God, these people could lie for [insert the name of your home country here].
"£$^&((*))*^ fraudsters. People actually believe this crap!

Ya

Unexpectedly, these observations revealed weak silicate emission features from the comet, rather than the anticipated strong silicate features found in some prior Oort Cloud comet observations, including those of Comet Hale-Bopp and studies conducted with the Spitzer Space Telescope... This composition challenges existing theoretical models of how Oort cloud comets form.

It would seam as if nothing, no amount of observation or measurement will falsify the dirty snowball nonsense.

Ya lost me at seam...

"science journalists who seem to be out to lie about every thing they write about!"

Can we get any more inane? It is in fact jonesdumb who is claiming the journalists lie about this and that. I merely read the article and made statements about that which I read. Contrary to jonesdumb's claims, the dirty snowball has been a failure on numerous aspects. Simply applying ad hoc adjustments is not the way science advancements are made, sometimes falsification requires a restart.

I would venture to say, a snowball can be "dirty" with carbon instead of silicates if it so desires...

Due to being scientifically impossible,

So the photoelectric effect is "scientifically impossible" on comets? Photons cannot reach the surface of a comets? Silly!

Well, silly....
Of course they can reach the surface of a comet. What your missing is that they have insufficient energy to actually cause it in any significant amount.
Safe to say, nowhere near the required amount to do the voodoo woo that you think it do...

Ah, sigh....the old argument that comets are 'dirty snowballs' former from the left overs of the solar system Vs the Electric Universe model. Well, the evidence is mounting in favour of the EU hypothesis regardless of your dogmatic scientific models that are being clung to.

The evidence is there for anyone with an open mind to see. Rubbishing the hypothesis without even assessing the evidence presented is neither open minded or the scientific process.

The electric force is present Everywhere. As is magnetism, and the failure of the mainstream to explain the often startling and unexpected observations they report and that can not be explained by the present model we have been using until now is plenty in my opinion to change model.

Science is all about finding a way to explain the world around us, not to put your head in the sand and say it can not be so because it does not fit with our model. Thats plain insanity in the truest way.

As if you would recognize an electric discharge if you saw it. The fact of the matter is the data shows a increase in brightness by a factor of ten. Then there is this nugget they admitted to;
"As such a high mass loading is inconsistent with the observed dust velocities, the free sublimation of water ice alone cannot explain the observed dust production."
And as is the M.O. of space scientists is to blame something "dark" or unseen to explain the event.

Ya lost me at seam...

Auto-spell/auto-replace on a phone, what are ya gonna do. The "artistic impression" is clear but you get hung up on spelling. At least we can see that you seem to prefer to not think.

As if you would recognize an electric discharge if you saw it. The fact of the matter is the data shows a increase in brightness by a factor of ten.

Yep, we would. It wouldn't have a spectrum that was fully consistent with light being reflected from dust and ice. It would be hot. It would leave a blindingly (literally) bright signature right across the EM spectrum. The velocity would not be ~ 20 m/s. Ergo, it was nothing like an electric discharge in any instrument.
10 times brighter than the nucleus, you say? Wow. The nucleus has an albedo of ~ 4%! So, let's say an albedo for the dust plume of 40%. Hell, make it double that, if you like:
https://en.wikipe...i/Albedo
And yes, the FREE sublimation of ice from the surface can't lift that much dust. That is,ice mixed with dust, just lying around sublimating. Hence why it would need a gas that is under pressure below the surface. We know there is ice below the surface. Not rocket science.

And as is the M.O. of space scientists is to blame something "dark" or unseen to explain the event.

Unlike Dunderdolts, invoking an invisible electric discharge! Or an invisible current powering the Sun! Or a non-existent pre-impact flash at Tempel 1, that managed to evade the instruments that would have seen it.! Sorry, but you are still in an evidence free zone. At least the possibilities offered by scientists in this case are based on things that we already know are scientifically possible, and fully in line with what is known about comets. I'm sure they would have included electric discharge as a possibility, if it were a) scientifically possible, and b) there was any evidence to suggest such a bizarre possibility. It isn't, and there wasn't.

The evidence is there for anyone with an open mind to see. Rubbishing the hypothesis without even assessing the evidence presented is neither open minded or the scientific process.

Nope. Zero evidence. The hypothesis is scientifically illiterate, and has been debunked in numerous places over the years. And, as I say, is an evidence-free zone. If you believe otherwise, point to the evidence. No woo sites, no press releases; actual science. You'll find that there is nothing.

.......Awaiting 'dark discharges' and 'conspiracy', 'cover-up', et boring cetera............

I'm still baffled about the EU rabids hearing thunder from across the vacuum of space during those invisible lightning discharges.

Perhaps this EU crapfest is a spin-off of aether nuttery? At least there would be a pseudo-physical medium to transmit the wrath of the Flying Tentacle Monster!

Hey! I just remembered. Crazy Great-Aunt Mendacious is a 'professional' 'medium'. Perhaps I can wheedle her into loaning me her brass spirit horn. Use it as a hearing device, I'm sure those mysterious interstellar blunderblasts would be audible then!

Who needs megabucks of technology and teams of brilliant researchers, when ya got a brass spirit horn and magic eyeglasses that farsee aetheric lightning across light years from a dark, damp basement.

Hence why it would need a gas that is under pressure below the surface. We know there is ice below the surface.

Right, so this loose agglomeration of of ices and dust is capable of creating the high pressure needed for this explosive event. You're right that isn't rocket science, it's not science.

I'm still baffled about the EU rabids hearing thunder from across the vacuum of space during those invisible lightning discharges.

There is no "vacuum of space", this is a pre-space age notion that was falsified by the very first in situ measurements taken by the very first spacecraft that entered space. Talk about blind, deaf, and dumb, such a moronic POV in the face of decades of direct measurement deserves no response, other than to point out how moronic you are.

Hence why it would need a gas that is under pressure below the surface. We know there is ice below the surface.

Right, so this loose agglomeration of of ices and dust is capable of creating the high pressure needed for this explosive event. You're right that isn't rocket science, it's not science.

Yes it is. Look it up in science papers, instead of woo sites. The surface, as found by MUPUS on Philae, is hard sintered ice/ dust. The icy/ dusty material is sitting on that surface. The thermal wave from heating reaches the ice below, that sublimates to gas, pressure can build. Like I say, not rocket science.
The fact that there were ice grains in the 'jet' constrains the temperature of that 'jet', doesn't it? Just as at Hartley 2, where CO2 was entraining H2O ice grains. So, whatever was going on, it was cooooold. Brrrrrr.

is hard sintered ice/ dust.

If you open your eyes you can clearly see geological features similar to planetary features such as cratering, layering of the rock, dunes, etc... But I'll give you sintering but it is sintering of rock. And being immersed in plasma this is how it would work.

http://www.scienc...14001080

Electric woo for Jones.
https://www.ncbi....5012123/

So you are now claiming that plasma spark discharge is the only way sintering can occur, @cantthink69?

Just so we have that clear.

But I'll give you sintering but it is sintering of rock. And being immersed in plasma this is how it would work.

Errrrrrrrrrr........................nope. Not rock. Nobody has ever detected rock on a comet. I'm sure I've quoted this before, but just for clarity, here we go again:

By comparison of arrival times at the individual feet, we estimate the propagation velocity of these Rayleigh waves to be at least 80 m/s. With the bulk density of 533 ± 6 kg/m3 as derived from tracking Rosetta (Pätzold et al., Nature, vol. 530, 2016), this velocity translates into a shear modulus of the comet material of at least 3.2 MPa. Shear modulus scales with velocity squared, so when taking into account the formal uncertainties arising from the arrival time inversion, the shear modulus may easily be as large as 10 MPa. This is still low compared to solid rock or monocrystalline ice, but is compatible with highly porous materials.

http://adsabs.har...42A..04K

The part of the above quote that EU wooists need to concentrate on is this:

This is still low compared to solid rock or monocrystalline ice, but is compatible with highly porous materials.

So, there they are telling us not only what the results are consistent with, but also what they are not consistent with. And that includes the elusive rock. And, of course, these results are also consistent with the findings of the CONSERT experiment, where they transmitted radio waves through one lobe of the comet, from Rosetta to Philae. The material has a permittivity value of 1.27. Good luck finding a rock with that value.
It is also consistent with the thermal inertia data from MIRO. And with the dirty great hole left in Tempel 1 by the impact there. And with a density of ~ 533 kg/m^3 of 67P.

I'm guessing this rock is in stealth mode, just like the invisible electric discharge woo.

Electric woo for Jones.
https://www.ncbi....5012123/

Huh? What has that got to do with Thornhill's woo? Looks like a perfectly mainstream paper to me. I remember reading it when it was first published. Nothing of any use to the wooists in there.

So you are now claiming that plasma spark discharge is the only way sintering can occur, @cantthink69?

Just so we have that clear.

I rather think CD is getting confused with the terminology, as usual. What he needs to be looking at is something like this:

Laboratory studies on cometary crust formation: The importance of sintering. (1992)
http://adsabs.har...oc..497R

I rather think CD is getting confused with the terminology, as usual.

It is yourself and the plasma ignoramuses which confuse the fact that we are discussing plasma phenomena here. The not electrically neutral comet is immersed in and interacting via plasma processes with the plasma of the solar wind. All the hypothetical beliefs regarding pressure and heat are meaningless without the consideration of the electrodynamic properties of the matter involved. jonesdumb is dramatically mistaken that his hypothetical electrically neutral guesses are valid.

I rather think CD is getting confused with the terminology, as usual.

It is yourself and the plasma ignoramuses which confuse the fact that we are discussing plasma phenomena here. The not electrically neutral comet is immersed in and interacting via plasma processes with the plasma of the solar wind. All the hypothetical beliefs regarding pressure and heat are meaningless without the consideration of the electrodynamic properties of the matter involved. jonesdumb is dramatically mistaken that his hypothetical electrically neutral guesses are valid.

Lol. Word salad. As usual. Any chance you've actually read any of the papers on the plasma environment at 67P? Or 1P/ Halley? Course you haven't. W*nk*r. Get an education. Yes?

I rather think CD is getting confused with the terminology, as usual.

It is yourself and the plasma ignoramuses which confuse the fact that we are discussing plasma phenomena here. The not electrically neutral comet is immersed in and interacting via plasma processes with the plasma of the solar wind. All the hypothetical beliefs regarding pressure and heat are meaningless without the consideration of the electrodynamic properties of the matter involved. jonesdumb is dramatically mistaken that his hypothetical electrically neutral guesses are valid.

Jeez, what a tosspot. Perhaps the uneducated loon can point to an author that we should be looking at.
Let's hear it Canthink. Who is this loon? Where are his predictions? Where has he been shown to be right? Let us all see. Why keep this a secret? This is Nobel Prize territory. Where is it? Lol.

How are scientists able to know that it is a comet's first pass through the inner solar system?

...the Oort Cloud, a zone of icy objects enveloping the solar system.

Say, what? Will someone please pinpoint the location of this mythical "cloud" because so far there has been ZERO confirmed observation of its existence.

Get with the reality, people. It JUST DOES NOT EXIST!

Which means that any hypothesis based on its existence is null and void.
Which means that comets will be a continual thorn in the side of the current nebular theory of planetary formation: How come there are still comets around if their lifespans are so limited and there's no known supply of new ones? What it boils down to is that a belief in the existence of the Oort cloud is based on an outright fabrication.

How are scientists able to know that it is a comet's first pass through the inner solar system?

From its orbit.

How are scientists able to know that it is a comet's first pass through the inner solar system?

From its orbit

This is of course based on the assumption that orbit cannot change, which is a fairly silly assumption.

How are scientists able to know that it is a comet's first pass through the inner solar system?

From its orbit

This is of course based on the assumption that orbit cannot change, which is a fairly silly assumption.

Of course it bloody changes - how do you think they end up in the inner system?? By looking at the orbital parameters, you can work out where it came FROM. How do you think, centuries ago, that we were able to predict the return of Halley's comet, among others?