New insights on comet tails are blowing in the solar wind

November 2, 2018 by Lina Tran, NASA's Goddard Space Flight Center
Comet McNaught over the Pacific Ocean. Image taken from Paranal Observatory in January 2007. Credit: ESO/Sebastian Deiries

Engineers and scientists gathered around a screen in an operations room at the Naval Research Laboratory in Washington, D.C., eager to lay their eyes on the first data from NASA's STEREO spacecraft. It was January 2007, and the twin STEREO satellites—short for Solar and Terrestrial Relations Observatory—which had launched just months before, were opening their instruments' eyes for the first time. First up: STEREO-B. The screen blinked, but instead of the vast starfield they expected, a pearly white, feathery smear—like an angel's wing—filled the frame. For a few panicky minutes, NRL astrophysicist Karl Battams worried something was wrong with the telescope. Then, he realized this bright object wasn't a defect, but an apparition, and these were the first satellite images of Comet McNaught. Later that day, STEREO-A would return similar observations.

Comet C/2006 P1—also known as Comet McNaught, named for astronomer Robert McNaught, who discovered it in August 2006—was one of the brightest comets visible from Earth in the past 50 years. Throughout January 2007, the fanned across the Southern Hemisphere's sky, so bright it was visible to the naked eye even during the day. McNaught belongs to a rarefied group of comets, dubbed the Great Comets and known for their exceptional brightness. Setting McNaught apart further still from its peers, however, was its highly structured tail, composed of many distinct bands called striae, or striations, that stretched more than 100 million miles behind the comet, longer than the distance between Earth and the Sun. One month later, in February 2007, an ESA (European Space Agency) and NASA spacecraft called Ulysses would encounter the comet's long tail.

"McNaught was a huge deal when it came because it was so ridiculously bright and beautiful in the sky," Battams said. "It had these striae—dusty fingers that extended across a huge expanse of the sky. Structurally, it's one of the most beautiful comets we've seen for decades."

How exactly the tail broke up in this manner, scientists didn't know. It called to mind reports of another storied comet from long ago: the Great Comet of 1744, which was said to have dramatically fanned out in six tails over the horizon, a phenomenon astronomers then couldn't explain. By untangling the mystery of McNaught's tail, scientists hoped to learn something new about the nature of comets—and solve two cosmic mysteries in one.

A key difference between studying comets in 1744 and 2007 is, of course, our ability to do so from space. In addition to STEREO's serendipitous sighting, another mission, ESA/NASA's SOHO—the Solar and Heliospheric Observatory—made regular observations as McNaught flew by the Sun. Researchers hoped these images might contain their answers.

Now, years later, Oliver Price, a planetary science Ph.D. student at University College London's Mullard Space Science Laboratory in the United Kingdom, has developed a new image-processing technique to mine through the wealth of data. Price's findings—summarized in a recently published Icarus paper—offer the first observations of striations forming, and an unexpected revelation about the Sun's effect on .

The first observations of striations forming have revealed new insights on the Sun's effect on comet dust tails. Credit: NASA's Goddard Space Flight Center/Genna Duberstein

Comets are cosmic crumbs of frozen gas, rock and dust left over from the formation of our solar system 4.6 billion years ago—and so they may contain important clues about our solar system's early history. Those clues are unlocked, as if from a time capsule, every time a comet's elliptical orbit brings it close to the Sun. Intense heat vaporizes the frozen gases and releases the dust within, which streams behind the comet, forming two distinct tails: an ion tail carried by the solar wind—the constant flow of charged particles from the Sun—and a dust tail.

Understanding how dust behaves in the tail—how it fragments and clumps together—can teach scientists a great deal about similar processes that formed dust into asteroids, moons and even planets all those billions of years ago. Appearing as one of the biggest and most structurally complex comets in recent history, McNaught was a particularly good subject for this type of study. Its brightness and high dust production made it much easier to resolve the evolution of fine structures in its dust tail.

Price began his study focusing on something the scientists couldn't explain. "My supervisor and I noticed weird goings-on in the images of these striations, a disruption in the otherwise clean lines," he said. "I set out to investigate what might have happened to create this weird effect."

The rift seemed to be located at the heliospheric current sheet, a boundary where the magnetic orientation, or polarity, of the electrified solar wind changes directions. This puzzled scientists because while they have long known a comet's ion tail is affected by the solar wind, they had never seen the solar wind impact dust tails before.

Dust in McNaught's tail—roughly the size of cigarette smoke—is too heavy, the scientists thought, for the solar wind to push around. On the other hand, an ion tail's miniscule, electrically charged ions and electrons easily sail along the solar wind. But it was difficult to tell exactly what was going on with McNaught's dust, and where, because at roughly 60 miles per second, the comet was rapidly traveling in and out of STEREO and SOHO's view.

"We got really good data sets with this comet, but they were from different cameras on different spacecraft, which are all in different places," Price said. "I was looking for a way to bring it all together to get a complete picture of what's happening in the tail."

The Sun's magnetic field, which is embedded in the solar wind, permeates the entire solar system. The current sheet -- where the magnetic field changes polarity --spirals out from near the solar equator like a wavy skirt around a ballet dancer's waist. Credit: NASA's Goddard Space Flight Center

His solution was a novel image-processing technique that compiles all the data from different spacecraft using a simulation of the tail, where the location of each tiny speck of dust is mapped by solar conditions and physical characteristics like its size and age, or how long it'd been since it'd flown off the head, or coma, of the comet. The end result is what Price dubbed a temporal map, which layers information from all the images taken at any given moment, allowing him to follow the dust's movements.

The temporal maps meant Price could watch the striations form over time. His videos, which cover the span of two weeks, are the first to track the formation and evolution of these structures, showing how dust fragments topple off the comet head and collapse into long striations.

But the researchers were most excited to find that Price's maps made it easier to explain the strange effect that drew their attention to the data in the first place. Indeed, the current sheet was the culprit behind the disruptions in the , breaking up each striation's smooth, distinct lines. For the two days it took the full length of the comet to traverse the current sheet, whenever dust encountered the changing magnetic conditions there, it was jolted out of position, as if crossing some cosmic speed bump.

"It's like the striation's feathers are ruffled when it crosses the current sheet," University College London planetary scientist Geraint Jones said. "If you picture a wing with lots of feathers, as the wing crosses the sheet, lighter ends of the feathers get bent out of shape. For us, this is strong evidence that the dust is electrically charged, and that the solar wind is affecting the motion of that dust."

Scientists have long known the solar wind affects charged dust; missions like Galileo Cassini, and Ulysses watched it move electrically charged dust through the space near Jupiter and Saturn. But it was a surprise for them to see the solar wind affect larger dust grains like those in McNaught's tail—about 100 times bigger than the dust seen ejected from around Jupiter and Saturn—because they're that much heavier for the solar wind to push around.

With this study, scientists gain new insights into long-held mysteries. The work sheds light on the nature of striated comet tails from the past and provides a crucial lens for studying other comets in the future. But it also opens a new line of questioning: What role did the Sun have in our solar system's formation and early history?

"Now that we see the solar wind changed the position of dust grains in McNaught's tail, we can ask: Could it have been the case that early on in the solar system's history, the played a role in organizing ancient dust as well?" Jones said.

Explore further: Soho prepares for comet McNaught

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cantdrive85
2.2 / 5 (20) Nov 02, 2018
Comets are cosmic crumbs of frozen gas, rock and dust

Obviously this is "rock", not rock...
"...For us, this is strong evidence that the dust is electrically charged, and that the solar wind is affecting the motion of that dust."

Heretics! Don't they know there are zero aspects of comets that are electric "woo"? jonesdumb needs to email the authors and set them straight.
Steelwolf
2.4 / 5 (17) Nov 02, 2018
I wonder which part of

"For us, this is strong evidence that the dust is electrically charged, and that the solar wind is affecting the motion of that dust."

jd is going to conflate and tell us is not possible, or that our theory excludes this effect.
cantdrive85
1.9 / 5 (17) Nov 02, 2018
jd is going to conflate and tell us is not possible, or that our theory excludes this effect.

Or that they knew it all along regardless of the non-predictions.
This also poses the question as to how the quasi-neutral SW can possibly affect these electric charges?
jonesdave
4 / 5 (16) Nov 02, 2018
Comets are cosmic crumbs of frozen gas, rock and dust

Obviously this is "rock", not rock...


It isn't rock. No rock has ever been detected at a comet. There are two types of dust; fluffy and compact. One weighs in a less than 1 kg/ m^3, the other at ~ 3000 kg/m^3. I've told you before - stop taking crap from PRs, and read the papers. You're as bad as the idiot Thornhill.
jonesdave
4.1 / 5 (14) Nov 02, 2018
Heretics! Don't they know there are zero aspects of comets that are electric "woo"? jonesdumb needs to email the authors and set them straight.


Thick b*stard!

DUSTY PLASMA EFFECTS IN COMETS; EXPECTATIONS FOR ROSETTA
Mendis, D. A. & Horányi, M. (and references therein).
https://agupubs.o...og.20005

Section 2, in particular.
jonesdave
4.2 / 5 (15) Nov 02, 2018
This also poses the question as to how the quasi-neutral SW can possibly affect these electric charges?


Negatively charged nano-grains at 67P/Churyumov-Gerasimenko
T. I. Gombosi, J.L.Burch, and M.Horányi.
https://www.aanda...6-15.pdf

How come you never know this stuff?

cantdrive85
1.6 / 5 (13) Nov 02, 2018
How come you never know this stuff?

You are the one who claims zero electric "woo" at comets, fact is comets are electric.
jonesdave
4.1 / 5 (13) Nov 02, 2018
How come you never know this stuff?

You are the one who claims zero electric "woo" at comets, fact is comets are electric.


No they aren't. Certainly not in the way the idiot Thornhill proposed. That is pure woo. EDM? Lol!
jonesdave
4.1 / 5 (14) Nov 02, 2018
Cometary surfaces, just like asteroid surfaces, can get charged up by a combination of the solar wind (electrons being more mobile), and the photoelectric effect.
The difference is that the comet has outgassing, which then puts that dust in the coma. Another difference is that the contribution from the SW to surface charging stops at a comet, as the SW fails to reach the surface for long periods during high activity.
Once in the coma, the dust can also undergo charging from the PE effect. And then you have the SW motional electric field, and stuff happens, basically. It is no great secret.
Here is a paper from 1985;

Trajectories of charged dust grains in the cometary environment
Horanyi, M. & Mendis, D. A.
http://adsabs.har...94..357H
jonesdave
4.1 / 5 (14) Nov 02, 2018
The paper for the above article is here;

Fine-scale structure in cometary dust tails I: Analysis of striae in Comet C/2006 P1 (McNaught) through temporal mapping.
Price, O. et al.
https://www.scien...18301192
cantdrive85
1.5 / 5 (16) Nov 02, 2018
Cometary surfaces, just like asteroid surfaces, can get charged up by a combination of the solar wind (electrons being more mobile), and the photoelectric effect.

Birkeland understood the consequence of these facts 110-years-ago, cathode jets are the result. He understood this because he was an experimentalist and he actually saw these results in the lab.
https://www.plasm...s_theory
The same way he predicted Birkeland currents creating the aurora. And take a look at the graph under "cometary charging" header. The brightness of comets is directly related to solar activity, more sunspots, the brighter the comets. It's electric discharging, whether the dark mode plasma of the SW, the glow mode plasma of the coma, or the cathode jets eroding the surface.
jonesdave
4 / 5 (12) Nov 02, 2018
Birkeland understood the consequence of these facts 110-years-ago, cathode jets are the result. He understood this because he was an experimentalist and he actually saw these results in the lab.


No he didn't, stop making shit up. And there are no cathode jets, you loon. Jesus, where do you get this sh!t from? Do you have a notebook of key EU words and names, and you just throw them into a sentence to make up some crappy story?

And take a look at the graph under "cometary charging" header. The brightness of comets is directly related to solar activity, more sunspots, the brighter the comets. It's electric discharging, whether the dark mode plasma of the SW, the glow mode plasma of the coma, or the cathode jets eroding the surface.


Hahaha. What an idiot. We just had a spacecraft around a comet for 2 years, you moron. None of this sh!t happened. And nobody in their right mind expected it to happen. Only scientifically illiterate pillocks like Thornhill.

jonesdave
4 / 5 (12) Nov 02, 2018
It's electric discharging, whether the dark mode plasma of the SW, the glow mode plasma of the coma, or the cathode jets eroding the surface.


You really have to wonder about the mental health of people who could not only come up with crap like that, but also that of the morons who are conned by it! Cathode jets! F*** me, where do they get this sh!t from? Lol.

archytype_net
1.9 / 5 (14) Nov 03, 2018
The amount of disdain for other possibilities is astounding! You folks have closed insignificant minds.

Electric and magnetic forces quite obviously play a major role in the structures observed. Gravitation does not explain it all, get it through your think skulls. Denying it and calling it sh1t is not a mature or scientific response.
jonesdave
3.9 / 5 (11) Nov 03, 2018
The amount of disdain for other possibilities is astounding! You folks have closed insignificant minds.

Electric and magnetic forces quite obviously play a major role in the structures observed. Gravitation does not explain it all, get it through your think skulls. Denying it and calling it sh1t is not a mature or scientific response.


Get your facts straight. These posts are by an idiot who believes comets were blasted off of rocky planets by thunderbolts created due to Velikovskian crap about Venus hurtling round the solar system a few thousand years ago. He thinks the jets, contrary to observation, are some sort of electric discharge nonsense. He thinks the volatiles observed are due to O- being machined from the comet by electric woo, combining with the solar wind ions, despite any number of observations that show that to be wrong. Et boring cetera.
Now, do you have anything useful to add?
cantdrive85
1.6 / 5 (13) Nov 03, 2018
Rosetta flew through a discharge jet, it's unequivocal. It was far too energetic and too much material to have been your fantasyland outgassing guesses. You already admitted to the conditions which allow cathode jets, charges impinging on the surface. Plasma phenomena such as what you explained occur in filaments, hence the cathode jets.

http://www.spaced...999.html
jonesdave
3.8 / 5 (10) Nov 03, 2018
Rosetta flew through a discharge jet, it's unequivocal. It was far too energetic and too much material to have been your fantasyland outgassing guesses. You already admitted to the conditions which allow cathode jets, charges impinging on the surface. Plasma phenomena such as what you explained occur in filaments, hence the cathode jets.

http://www.spaced...999.html


Complete crap. Stop making sh!t up. If Rosetta flew through a discharge jet (lol!), then show me what registered on the magnetometer. Or in UV. Or any other instrument that would give us pause to wonder. No PRs, actual papers dealing with the instrumental detections. Quit with the lying.
jonesdave
4.1 / 5 (9) Nov 03, 2018
You already admitted to the conditions which allow cathode jets, charges impinging on the surface.


No, I didn't. Where did that happen? Surfaces get charged, such as asteroids, moons, comets. Nobody in their right mind is invoking cathode jets to explain anything at those bodies. Only unqualified woo merchants. You'll find nothing in the scientific literature.
jonesdave
3.7 / 5 (9) Nov 03, 2018
So, let's start with the abstract of the paper that covers this particular event;

Evidence of sub-surface energy storage in comet 67P from the outburst of 2016 July 03
Agarwal, J. et al
https://academic..../4565550

On 2016 July 03, several instruments onboard ESA's Rosetta spacecraft detected signs of an outburst event on comet 67P, at a heliocentric distance of 3.32 au from the Sun, outbound from perihelion. We here report on the inferred properties of the ejected dust and the surface change at the site of the outburst. The activity coincided with the local sunrise and continued over a time interval of 14–68 min. It left a 10-m-sized icy patch on the surface. The ejected material comprised refractory grains of several hundred microns in size, and sub-micron-sized water ice grains............


Cont....

jonesdave
3.7 / 5 (9) Nov 03, 2018
Cont..........

.........The high dust mass production rate is incompatible with the free sublimation of crystalline water ice under solar illumination as the only acceleration process. Additional energy stored near the surface must have increased the gas density. We suggest a pressurized sub-surface gas reservoir, or the crystallization of amorphous water ice as possible causes.


So, what should we see if this was some sort of ill defined electric woo? Please let us know, and then we can go from there.

Steelwolf
2 / 5 (12) Nov 03, 2018
Instead jd goes and totally Ignores the major portion of the article:

"...this is strong evidence that the dust is electrically charged, and that the solar wind is affecting the motion of that dust."

Everything beyond that statement is just supporting material, the fact that JD studiously ignores this fact is proof of his own ignorance (self imposed) on this matter.

JD is not competent to make any statements on the actual science involved as he only links studies to his own cherry picked data that proves his point if only that small subset of the data is considered.

When all the data is in, Electromagnetism is on par with, and actually covers greater distances than does gravity. Even though it is a weaker force by an order of magnitude at long distances, it is also stronger than gravity in the close regime.
jonesdave
3.8 / 5 (10) Nov 03, 2018
Instead jd goes and totally Ignores the major portion of the article"
...this is strong evidence that the dust is electrically charged, and that the solar wind is affecting the motion of that dust."


So you didn't bother reading the papers I linked going back to 1985? There are absolutely shed loads more. Want me to link them? Your problem is that you don't understand them. So you just quote bits of papers that you, in your ignorance, think supports your idiotic beliefs, when it does nothing of the kind.

jonesdave
3.7 / 5 (9) Nov 03, 2018
When all the data is in, Electromagnetism is on par with, and actually covers greater distances than does gravity.


No it isn't. Can't do sh!t about galaxy rotation curves, for instance. Can't do anything with planetary orbits. Doesn't affect satellite orbits around planets. Etc.

jonesdave
3.8 / 5 (10) Nov 03, 2018
Instead jd goes and totally Ignores the major portion of the article:

"...this is strong evidence that the dust is electrically charged, and that the solar wind is affecting the motion of that dust."


Screw the article, I read the freely available paper. You obviously missed this;

The McNaught observations confirm that solar wind conditions can have a significant effect on observable dust tail structure. We believe that the most likely cause of the observed effects are due to changes in the Lorentz force, as previously predicted (Horanyi and Mendis, 1987).


Hmmm, not postdicted by Thornhill & Talbott in 2018, but predicted 31 years ago by real scientists. Funny that, eh?

jonesdave
3.7 / 5 (9) Nov 03, 2018
And here is the 1987 paper mentioned above;

The effect of a sector boundary crossing on the cometary dust tail
Horanyi, M. & Mendis, D. A
http://adsabs.har...37...71H
cantdrive85
1.6 / 5 (13) Nov 03, 2018
Evidence of sub-surface energy storage in comet 67P from the outburst of 2016 July 03
Agarwal, J. et al

Just shows the comet is a charged object in plasma, otherwise known as a cathode. And jets are erupting from the cathode, AKA, cathode jets.
cantdrive85
1.6 / 5 (13) Nov 03, 2018
. We suggest a pressurized sub-surface gas reservoir, or the crystallization of amorphous water ice as possible causes.

It's a guess put forth by plasma ignoramuses, only conjectured due to the fact the outburst exceeded predictions. The guesses based on your fantasyland physics failed so something dark and unseen was contrived, this is the SOP of the darkists.
jonesdave
3.7 / 5 (9) Nov 03, 2018
Evidence of sub-surface energy storage in comet 67P from the outburst of 2016 July 03
Agarwal, J. et al

Just shows the comet is a charged object in plasma, otherwise known as a cathode. And jets are erupting from the cathode, AKA, cathode jets.


No it doesn't. You are lying again. Dust and ice, woo boy. Stop making sh!t up. Idiot.
jonesdave
3.7 / 5 (9) Nov 03, 2018
. We suggest a pressurized sub-surface gas reservoir, or the crystallization of amorphous water ice as possible causes.

It's a guess put forth by plasma ignoramuses, only conjectured due to the fact the outburst exceeded predictions. The guesses based on your fantasyland physics failed so something dark and unseen was contrived, this is the SOP of the darkists.


Sorry? And what do the mag data say? What did Alice see in UV? No discharges, idiot. That is just a bunch of unscientific woo invented by a plasma ignoramus. In fact, a science ignoramus. Please show me where an actual scientist has ever suggested cathode jets (lol!, you couldn't make this sh!t up; whoops, they did!) can occur at comets, or asteroids etc.
You are talking out of your uneducated arse. As per usual.
cantdrive85
1.4 / 5 (11) Nov 03, 2018
Can't do sh!t about galaxy rotation curves, for instance.

Oh the irony, given the fact Dr Scott produced a model of Birkeland currents explaining those very rotation curves. Experiment, observation, maths, prediction, and confirmation, you know, science.
jonesdave
3.7 / 5 (9) Nov 03, 2018
JD is not competent to make any statements on the actual science involved as he only links studies to his own cherry picked data that proves his point if only that small subset of the data is considered.


So, link to your own papers that you think prove whatever it is that you are trying to prove. Don't exist, do they?

jonesdave
3.5 / 5 (8) Nov 03, 2018
Can't do sh!t about galaxy rotation curves, for instance.

Oh the irony, given the fact Dr Scott produced a model of Birkeland currents explaining those very rotation curves. Experiment, observation, maths, prediction, and confirmation, you know, science.


No, he didn't. The idiot Scott produced a piece of crap, in a crank journal, where he fuxxes up the maths, and still doesn't even consider how his non-existent mechanism can move a star at the observed rates. It is junk, and he is a loon.
jonesdave
3.4 / 5 (9) Nov 03, 2018
Can't do sh!t about galaxy rotation curves, for instance.

Oh the irony, given the fact Dr Scott produced a model of Birkeland currents explaining those very rotation curves. Experiment, observation, maths, prediction, and confirmation, you know, science.


****NOTE TO PHYS.ORG EDITORS****

A retired EE, with no qualifications in astrophysics or plasma physics, has explained GR curves, and done away with the need for DM! How did you manage to miss this Nobel Prize worthy 'paper'? Shame on you! Lol.
rrwillsj
3.5 / 5 (8) Nov 03, 2018
Comets are plasma.... hahahaha! Really cant? This Solar System is surrounded by shells of comets. If they are plasma, why weren't those self-consumed billions of years ago? Unless of course it's some sort of magical perpetual-motion plasma?

Would not your perpetual-motion magic-plasma be perpetually radiating? No matter how far from the Sun? Considering the myriad of comets, wouldn't the radiating light block out the view beyond the Oort Cloud?

Yet it is only when the iceballs orbital paths pull them within the Hills-Oort shells & the Kuiper Belt & the Neptune-Uranus region, that the comets become visibly active. Before that (phase-change?) they are only being effected by gravity and random chance.

If your magic-plasma woo had any validity? Those objects would not need to gain energy from proximity to either the Sun or the Solar Wind, to display how energetic plasma-comets would be.

Well, not in this Universe! Perhaps in some magical-faerie universe?

cantdrive85
1.4 / 5 (10) Nov 03, 2018
Comets are plasma.... hahahaha! Really cant?

And I said that where? You and jonesdumb are quite apt at lying through your teeth. Comets are charged objects immersed in plasma.
jonesdave
3.7 / 5 (9) Nov 03, 2018
Comets are plasma.... hahahaha! Really cant?

And I said that where? You and jonesdumb are quite apt at lying through your teeth. Comets are charged objects immersed in plasma.


So are asteroids and so is the Moon. So what? Not a single scientist is claiming the crap that you are.
jonesdave
3.7 / 5 (9) Nov 03, 2018
You and jonesdumb are quite apt at lying through your teeth.


Nope. Don't need to lie to discredit this already debunked unscientific garbage. You are the one that needs to keep lying to keep it alive in your own feeble mind. Cathode jets! Lol. Deary me.
cantdrive85
1.5 / 5 (8) Nov 04, 2018
Don't need to lie to discredit this already debunked unscientific garbage.

You claim you don't need to, yet constantly do so. The comets absorbs ions and emits electrons, and is a charged object in plasma. It fits the description of a cathode, and the cathode has jets, i.e. cathode jets.
cantdrive85
1.5 / 5 (8) Nov 04, 2018
It can also be noted, the same form appeared in Earth's atmosphere following the Starfish nuclear test.
http://blogs.disc...KqzllAwA
As above, so below...
jonesdave
3.4 / 5 (5) Nov 04, 2018
Don't need to lie to discredit this already debunked unscientific garbage.

You claim you don't need to, yet constantly do so. The comets absorbs ions and emits electrons, and is a charged object in plasma. It fits the description of a cathode, and the cathode has jets, i.e. cathode jets.


Wrong. As I said, you moron, the same thing happens to asteroids and moons, and, in fact, spacecraft. And has been known about for bloody decades. Nobody has been dumb enough to claim cathode jets at any of those objects. Have they? So why are you, you arse?
jonesdave
3.4 / 5 (5) Nov 04, 2018
It can also be noted, the same form appeared in Earth's atmosphere following the Starfish nuclear test.
http://blogs.disc...KqzllAwA
As above, so below...


What the hell has that got to do with solar wind effects on a comet tail at ~ 60m km from the comet? What are you smoking, woo boy?
jonesdave
3.4 / 5 (5) Nov 04, 2018
The comets absorbs ions and emits electrons


Missed this piece of dumbness. Where is this happening? Comet, asteroid, moons absorb photons, and emits electrons, you arse. And that on the sunlit side only. Causing that side to charge up a few volts +. Solar wind electrons have a larger gyroradius than ions, so can reach the unlit side of said bodies, causing them to charge up negatively.
jonesdave
3.4 / 5 (5) Nov 04, 2018
The comets absorbs ions and emits electrons


The only ions absorbed by solar system bodies, are on those unprotected by an atmosphere. Such as asteroids, the Moon, and comets when they are at low activity. This just leads to sputtering, where the incident ion releases a neutral atom from the surface.

Solar wind sputtering of dust on the surface of 67P/Churyumov-Gerasimenko
Wurz, P. et al.
https://www.aanda...01525980
rrwillsj
3 / 5 (4) Nov 04, 2018
Some vague notion kept pestering the back of my mind about my comment.
"... {real existing comets} are only being effected by gravity and random chance.{out beyond Saturn's orbit} ..."

Should be corrected to "... are only being effected by gravity and random collisions. ..."

Which led me to wonder, when we have closely, carefully, inspected a number of comets? How many of those would actually be pristine ancients?

And how many will prove out to br conglomerates of multiple collision and restructuring events?

The sheer numbers of comets and other objects, Even across the vastness of Trans-Neptune Space and the vast cubic separating objects? Over billions of years, a percentage have to been playing Whack-A-Mole with one another!

Which means we should not presume the accouchement for any comet. With some, undetermined, probability that what we are observing may turn out to be the product of a recent clumping of perversely diverse bits and pieces from different ages.
jonesdave
3.4 / 5 (5) Nov 04, 2018
"... are only being ***effected*** by gravity and random collisions. ..."


Affected. :) And gravitational effects, such as is caused by outgassing affecting spin rate.
Steelwolf
2.6 / 5 (5) Nov 04, 2018
Jd is calling 'outgassing a 'gravitational effect'?^^^^^

And where are all of Your papers, jd, if you want to go that game.
jonesdave
3.4 / 5 (5) Nov 04, 2018
Jd is calling 'outgassing a 'gravitational effect'?^^^^^

And where are all of Your papers, jd, if you want to go that game.


Whoops - ***non***-gravitational effects. Which was my point to rwillsj. Well done for spotting the deliberate mistake.

https://www.hou.u...6155.pdf
Steelwolf
3.4 / 5 (5) Nov 04, 2018
We have long known solar wind affected the charged ionic trail, but (as taken from article above):

"...This puzzled scientists because while they have long known a comet's ion tail is affected by the solar wind, they had never seen the solar wind impact dust tails before."

And yet it is that 'neutral' dust that was obviously affected due to the changing current conditions they went through. So jd is obviously missing the very point of this article, or devoutly ignoring it and trying to conflate the argument to something else.

Too Bad, Electrical events and current sheets happen to affect neutral dusts as well as ionic ones. Proof is in the papers!

Solon
4.3 / 5 (3) Nov 04, 2018
JD
"It isn't rock. No rock has ever been detected at a comet."

Characterization of OSIRIS NAC filters for the interpretation of multispectral data of comet 67P/Churyumov-Gerasimenko⋆

https://www.aanda...-15.html

jonesdave
3.4 / 5 (5) Nov 04, 2018
And yet it is that 'neutral' dust that was obviously affected due to the changing current conditions they went through. So jd is obviously missing the very point of this article, or devoutly ignoring it and trying to conflate the argument to something else.


Sigh. How many bloody times? Why are you loons incapable of understanding a simple paper, with references to previous papers? Hmmm? As pointed out, this is expected, and had been modelled by Horanyi & Mendis back in the 80s. The dust is not all neutral, as I have pointed out repeatedly. It can get charged on the surface, and it can get charged in the coma (from the photoelectric effect).

jonesdave
3.4 / 5 (5) Nov 04, 2018
JD
"It isn't rock. No rock has ever been detected at a comet."

Characterization of OSIRIS NAC filters for the interpretation of multispectral data of comet 67P/Churyumov-Gerasimenko⋆

https://www.aanda...-15.html



And what are you misunderstanding in that paper, pray tell?
jonesdave
3.4 / 5 (5) Nov 04, 2018
JD
"It isn't rock. No rock has ever been detected at a comet."

Characterization of OSIRIS NAC filters for the interpretation of multispectral data of comet 67P/Churyumov-Gerasimenko⋆

https://www.aanda...-15.html



And what are you misunderstanding in that paper, pray tell?


Probably didn't read this far;

Comets are believed to be formed by primordial ***dusty*** ice material during the formation of the early solar system (Weidenschilling 2004). Their ***dust*** is a mixture of silicates, both amorphous and crystalline, Fe-Ni sulfides, small amounts of oxides, and other minerals. The most common cometary silicates are the Mg-rich olivine (forsterite, Fo: Mg2SiO4) and Mg-rich pyroxene (enstatite, En: Mg2Si2O6) (Hanner & Zolensky 2010).


jonesdave
3.4 / 5 (5) Nov 04, 2018
And yet it is that 'neutral' dust that was obviously affected due to the changing current conditions they went through.


Have you actually read that paper? If you have, then you are not understanding it. Surprise, surprise. The dust takes on the strange appearance we see due to the oppositely directed magnetic fields above and below the heliospheric current sheet. Nothing to do with currents. Magnetic field. Get it?

Steelwolf
2.6 / 5 (5) Nov 04, 2018
There is the problem jd, it was 'modeled', only now do they have the definitive proof, and it happens to occur along that current sheet you are still ignoring (and claim does not happen like that), and in doing so making our points for us, as Magnetic is Exactly what we have been pointing out Thanks! Much appreciated.
jonesdave
3.4 / 5 (5) Nov 04, 2018
There is the problem jd, it was 'modeled', only now do they have the definitive proof, and it happens to occur along that current sheet you are still ignoring (and claim does not happen like that), and in doing so making our points for us, as Magnetic is Exactly what we have been pointing out Thanks! Much appreciated.


In which case you were beaten to it by 30 odd years. So you are telling us nothing, correct? And it doesn't occur along the current sheet, liar. Learn to read, you clueless loon.

granville583762
3 / 5 (6) Nov 04, 2018
A Cometary tail

Ice covered dust
Ice covered rock fragments
Comet valleys covered in rock fragments
Slabs of rock strewn around the comet
The ice covered dust rains down as snow
As it blows in the cosmic wind
As charged snow
Stretching millions of miles
In the solar wind
Electrically charged
With its magnetic field
Induced as electric
Fields in motion
In the solar wind
Where
No two
Comets
Are identical
As they tumble in their orbits
Strewing their dusty frozen valleys
In a cloud of electrically charged snow
Falling as snow
On their valley floors
Becoming their tail
A tail that is different
As each comet is unique
Old_C_Code
3 / 5 (2) Nov 04, 2018
it happens to occur along that current sheet


There is no current sheet in our solar system. 6 atoms per cubic meter is not a sheet. It's as good an insulator as zero atoms per cubic meter.
jonesdave
3.7 / 5 (6) Nov 04, 2018
it happens to occur along that current sheet


There is no current sheet in our solar system. 6 atoms per cubic meter is not a sheet. It's as good an insulator as zero atoms per cubic meter.


Sorry, OCC, but there is. The heliospheric current sheet. It is nothing to do with the ion and electron density, though. It is caused by the Sun having oppositely directed magnetic fields in its N and S hemispheres. As these oppositely directed fiels meet, roughly around the ecliptic, then a current sheet must form.

https://en.wikipe...nt_sheet
Solon
2.3 / 5 (3) Nov 04, 2018
JD
"Nothing to do with currents. Magnetic field. Get it?"

=#
jonesdave
3.4 / 5 (5) Nov 04, 2018
JD
"Nothing to do with currents. Magnetic field. Get it?"

=#


And your problem is......? The currents that create the magnetic field are deep within the Sun. See 'dynamo theory'. They are not affecting the charged dust. What is it with you unqualified loons? Does everything need to be explained to you?
Ultron
1 / 5 (3) Nov 04, 2018
How do they know, that this effect is due to Solar wind? Its only unconfirmed guess.

I think it is good example of how we miss major part in gravity theory.
Old_C_Code
5 / 5 (1) Nov 04, 2018
Sorry, OCC, but there is.


Ok, got it, but that's a closed loop from heliosphere to Sun. No galactic current (wipes brow).
Solon
3 / 5 (2) Nov 04, 2018
JD
"Comets are believed to be formed by primordial ***dusty*** ice material..."

By the old school, yes. You're obsolete. Silicates and other rock ***contain*** water.
jonesdave
3.9 / 5 (7) Nov 04, 2018
Sorry, OCC, but there is.


Ok, got it, but that's a closed loop from heliosphere to Sun. No galactic current (wipes brow).


No net current, no.
jonesdave
3.4 / 5 (5) Nov 04, 2018
How do they know, that this effect is due to Solar wind? Its only unconfirmed guess.


It isn't the solar wind, per se. It is the magnetic field carried by the solar wind, the IMF.
granville583762
2.7 / 5 (7) Nov 04, 2018
Where a comet meets its destiny

Solar magnet field
Is the plasmas electric field in motion
As rising bubbling plasma
From the core
Ionic plasma in motion
Electric fields in motion
is the solar magetic field
Producing magnetic fields
Driving the plasma
In magnetic sling shots
In coronal mass ejections
Extending millions of miles into space
Driving the solar furnace
And the solar wind
A light year into space
An ionic electric field in motion
Is a solar magnetic wind
As Solarwind of Magnetic fields
Stretching a light year
To the heliosphere
Where the solar gravitational field of influence
Extends up to two light years
Which coincidently
Say a considerable sum
For Sagittarius A*s gravitational field
When our suns gravitational field Is felt at two light years
rrwillsj
5 / 5 (2) Nov 04, 2018
Sorry jd but I just gotta to call you on this one. I reserve "affect" for emotional language. I intentionally use "effect" for active, physical causation.

Next we could debate "Oxford commas" (I hatem!) and double-spacing between sentences. (also my preference)
cantdrive85
1.8 / 5 (5) Nov 04, 2018
It is the magnetic field carried by the solar wind, the IMF.


"It is the magnetic field created by the solar wind, the IMF."

Fixed that for ya.
Da Schneib
4.2 / 5 (5) Nov 04, 2018
Magnetic fields are the inevitable relativistic correction for the lightspeed limitation of the action of the electromagnetic force. They are not caused or "created" by anything, except whatever "causes" the EM force. Which is electric charge.
granville583762
3 / 5 (6) Nov 04, 2018
The solar magnetic field dynamo

Is the rising bubbling plasma
From the solar core
An ionic plasma in motion
Is creating multitudes of magnetic fields
As the solar surface
Is a seething mass of magnetic fields
Which are the solar sunspots
As these magnetic fields hurl ionic plasma
Into the vacuum
As the solar wind as ionic plasma in motion
Producing magnetic fields
Because this is ionic plasma electric fields in motion
Interacting with the solar totality magnetic field
This reverses polarity every eleven years
Where electrons within the solar wind plasma
Encircling the magnetic lines of field in synchrotron radiation
Emitted from this solar wind

Where the solar magnetic dynamo
Is the rising bubbling plasma
Electric fields in motion
Producing magnetic fields
Da Schneib
4 / 5 (4) Nov 04, 2018
Sorry, OCC, but there is.


Ok, got it, but that's a closed loop from heliosphere to Sun. No galactic current (wipes brow).
Saying "heliosphere to Sun" is like saying "atmosphere to Earth." Meaningless from a Solar System perspective. They're both the same thing.
granville583762
3 / 5 (6) Nov 04, 2018
Current sheets, magnetically expelled currents

Current sheets are electric currents that are confined to the surface of plasma. Current sheets is the behaviour of electrically conductive plasma, electric current through part of the plasma electrically produced magnetic fields expel the currents from the plasma compressing the current into thin layers that pass through the plasma.

This is the same in superconducting coils; the current is expelled to a thin outer layer by the magnetic fields
granville583762
3 / 5 (6) Nov 04, 2018
Current sheets, magnetically expelled currents
Whereas these magnetically expelled currents, as a thin sheet encircling long strands of plasma, compress the plasma as a current sheet
granville583762
3 / 5 (6) Nov 04, 2018
Except there is a little flaw in these currant sheets, the currant is encircled by perpendicular circular expanding magnetic fields
The currant is not expelled; the magnetic field is expelled as the magnetic field is compressing the currant in the process of expanding, and if this current forms a complete loop, a dipole will form in the torus shaped loop!
granville583762
3 / 5 (6) Nov 04, 2018
Current loops are the solar sunspot magnetic fields

It is this current forms a complete loop, forming a dipole in the loops of plasma
Which is are the rising and falling of the solar bubbling plasma is the torus shaped loops
It is forming complete current loops so forming dipoles which are the myriad of suns spots
That covers the solar surface of solar granulations
cantdrive85
1.7 / 5 (6) Nov 04, 2018
Sorry, OCC, but there is.


Ok, got it, but that's a closed loop from heliosphere to Sun. No galactic current (wipes brow)

There was a time when it was thought the Earth was isolated from the Sun, Birkeland suggested otherwise. He was correct. There is no reason to think the Sun isn't also connected to a larger circuit, the observation that several nearby stars also have a 22-year-cycle suggests this is true.
Da Schneib
4 / 5 (4) Nov 04, 2018
@cantthink69 makes up another lie.

How many times do you think this is gonna work, @cantthink?
granville583762
4 / 5 (4) Nov 05, 2018
Ions in currant sheets

Current sheets, currents expelled to the surface of plasma
Current produced by moving charged ions within the plasma
As electric fields in motion
The electric current is the collection of individual ions
That current cannot be expelled
To the plasmas surface
Because
The ions
With their electric field
still remain
In their relative position
Within the plasma
The ions are the current
As without the ions
Being expelled
To the plasmas surface
There will be no
Currant sheet at the plasmas surface
Otherwise
All the ions will have
To be expelled to the plasma surface
jonesdave
3 / 5 (4) Nov 05, 2018
Sorry, OCC, but there is.


Ok, got it, but that's a closed loop from heliosphere to Sun. No galactic current (wipes brow)

There was a time when it was thought the Earth was isolated from the Sun, Birkeland suggested otherwise. He was correct. There is no reason to think the Sun isn't also connected to a larger circuit, the observation that several nearby stars also have a 22-year-cycle suggests this is true.


Wrong. And not a single scientist has ever suggested such nonsense.
jonesdave
3 / 5 (4) Nov 05, 2018
It is the magnetic field carried by the solar wind, the IMF.


"It is the magnetic field created by the solar wind, the IMF."

Fixed that for ya.


Wrong, and not a single scientist has ever suggested such a thing.
jonesdave
2.3 / 5 (3) Nov 05, 2018
Birkeland suggested otherwise. He was correct.


And wasn't the first.
Steelwolf
3 / 5 (4) Nov 05, 2018
jd, from the article:
"The rift seemed to be located at the heliospheric current sheet, a boundary where the magnetic orientation, or polarity, of the electrified solar wind changes directions."

Where you exclaim, up and down, that it does not happen there and that the above story does not reference and I am a liar. Well, to rub your nose in all of those statements, the above quote, taken from above article will Hopefully make you sit back and consider that you have been WRONG for a long time here. Go away, troll, you have been shown through.

And we HAVE been trying to show you this 'Woo' is NOT out of mainstream, just YOU are.
jonesdave
3 / 5 (4) Nov 05, 2018
"The rift seemed to be located at the heliospheric current sheet, a boundary where the magnetic orientation, or polarity, of the electrified solar wind changes directions."

Where you exclaim, up and down, that it does not happen there and that the above story does not reference and I am a liar.


You are a liar. Of course it bloody happens there, you idiot! And that is what I have been saying. The HCS only exists because of the oppositely directed magnetic fields in the N and S hemisphere of the Sun! The HCS is a very thin layer (~ 10 000 km thick). So, on one side of it the dust is affected by the Lorentz force of a magnetic field of opposite polarity than on the other side. Hence the pretty pictures. You simply have zero to negligible understanding of astrophysics. Like I keep saying, this was predicted, by real scientists, over 30 years ago. You are not saying anything that wasn't already known.
granville583762
3.4 / 5 (5) Nov 05, 2018
Plasma in circular motion is a current sheet

There is only one way the plasmatic ions are going to be expelled to the circumference
A current loop of circulating ions
Electric field in motion
Producing a dipole through the torus central axis
Where there is an increased density of ions
Repelled by the magnetic fields
In concentrated form
Passing through
The central torus
This is not a continouse
Linear solar wind
But a circular currant loop
And it is not a complete current sheet
But only covering the outer circumferential surface
As the ions are not expelled
But
Stay within the magnetic fields
Steelwolf
2.6 / 5 (5) Nov 05, 2018
And you, in the above post declared that it does NOT happen there:

"In which case you were beaten to it by 30 odd years. So you are telling us nothing, correct? And it doesn't occur along the current sheet, liar."

So, I call you the big Liar, who constantly lies about science and then lies about what he said to cover what he mis-said before.

jd (lower case) go away and get real, learn how to read yourself, learn how to not conflate data and argue just because you do not like the poster when they know more than you.

You have proven yourself to be a lying fraud for the past 5 years, and people of all walks have consistently called you on it. Are you a masochist or just stupid?
Old_C_Code
1 / 5 (1) Nov 05, 2018
Steel: it's a closed loop about the Sun, there is no energy coming into the Sun, just leaving the Sun. Where is evidence there is energy entering the Sun?
jonesdave
3 / 5 (4) Nov 05, 2018
In which case you were beaten to it by 30 odd years. So you are telling us nothing, correct? And it doesn't occur along the current sheet, liar."

So, I call you the big Liar, who constantly lies about science and then lies about what he said to cover what he mis-said before.


Idiotic cretin. Listen, yes? It was not travelling ***ALONG*** the HCS . Comprende? That is where you are lying, or too stupid to understand the paper. It travelled from one side of the HCS to the other, you clown. The magnetic field has different polarity above and below the HCS. Christ, how difficult can this be?
You also lied when you stated;
And yet it is that 'neutral' dust that was obviously affected due to the changing current conditions they went through


Nothing to do with the bloody current, you imbecile.

jonesdave
2.3 / 5 (3) Nov 05, 2018
The most obvious reason for such an observable change coincident with the HCS crossing is the expected large change in the Lorentz force acting on electrically charged particles. The Lorentz force is associated with the motional electric field generated by the solar wind flow past the comet. A reversal in heliospheric magnetic field direction associated with a HCS crossing would result in a potentially dramatic change in direction of the Lorentz force. Electrically charged grains south of the HCS would therefore be accelerated in a different direction to that induced by the Lorentz force direction north of the HCS. Such an observable effect associated with a HCS crossing was predicted by Horanyi and Mendis (1987), and described more recently by Mendis and Horányi (2013).


From the paper.
jonesdave
2.3 / 5 (3) Nov 05, 2018
Thickness of HCS = ~ 10 000 km. Comet velocity = ~ 60 km/s. Time to traverse HCS = ~ 3 minutes. Dust velocity = bugger all. Dust released south of HCS has Lorentz force acting on it in one direction. Dust eventually crosses HCS. Lorentz force from oppositely directed field accelerates dust in opposite direction. Hence pretty picture. Anybody struggling to keep up here?
Steelwolf
3 / 5 (4) Nov 05, 2018
You DO understand that the Lorentz force is that exerted by a magnetic field on a moving electric charge, and thus electricity flow AND a magnetic field are required, and that, yes, they have a major effect on mass. What part of that do you not understand?
jonesdave
3 / 5 (4) Nov 05, 2018
You DO understand that the Lorentz force is that exerted by a magnetic field on a moving electric charge,


Errr, yes. And? What are you prattling on about now? We know the dust is charged. I have explained how that happens. So the Lorentz force acts in different directions N and S of the HCS. Honestly, why are you still commenting on this? Read the paper, and the Horanyi * Mendis paper, and at least try to understand them.

.... and thus electricity flow AND a magnetic field are required


Electricity flow? What? These are just charged dust grains.

.....yes, they have a major effect on mass


No they don't. The Lorentz force is doing nothing to a planet or a star. What is your point?
Steelwolf
3 / 5 (4) Nov 05, 2018
And this from the abstract, some 5 years ago:
"The measured field strengths and the similarity of field patterns and flow patterns of the diffuse ionized gas give strong indication that galactic magnetic fields are dynamically important. They may affect the formation of spiral arms, outflows, and the general evolution of galaxies."

from: https://arxiv.org...5663.pdf

So, please reconsider where mainstream astronomy really is jd, you are at least 5 years behind the times.
jonesdave
3 / 5 (4) Nov 05, 2018
And this from the abstract, some 5 years ago:
"The measured field strengths and the similarity of field patterns and flow patterns of the diffuse ionized gas give strong indication that galactic magnetic fields are dynamically important. They may affect the formation of spiral arms, outflows, and the general evolution of galaxies."

from: https://arxiv.org...5663.pdf

So, please reconsider where mainstream astronomy really is jd, you are at least 5 years behind the times.


And what has that got to do with the price of fish? 5 years behind what? What are you gish-galloping about now? Magnetic fields DO NOT affect rotation curves. End of story.
cantdrive85
1 / 5 (2) Nov 06, 2018
As usual, the plasma ignoramuses have it backwards. The HCS is primary to the magnetic fields, electric currents create magnetic fields.
jonesdave
5 / 5 (1) Nov 06, 2018
As usual, the plasma ignoramuses have it backwards. The HCS is primary to the magnetic fields, electric currents create magnetic fields.


Wrong. Stop commenting on stuff that you don't understand.
Steelwolf
2.3 / 5 (3) Nov 06, 2018
juniordave might take his own advice and stop posting on all these things he is at least a decade behind on, and refuses to learn. In order for a mind to work it must be open to new data and be able to process it. jd has neither ability, as he has amply, by himself, proven to all here beyond doubt. "when wrong attack the deliverer or change directions, pivot, spin" you must be a right wing politico too eh since only ancient, dead facts fill your head?

jd no longer understands how far into acceptance the major strengths of EM and Plasma theory combined has come, and how many of the old placemarkers it gets rid of automatically. So many things we had thought to be absolute truth have been shattered by recent new data, and yet jd is unable to assimilate it.

To the other readers, I apologize, but one can be baited by an idiot only so long before one Needs to respond properly. jd is an idiot wearing said old Emperor's clothes, the ones the kid commented on not seeing, jd does tho.
jonesdave
5 / 5 (1) Nov 06, 2018
So many things we had thought to be absolute truth have been shattered by recent new data, and yet jd is unable to assimilate it.


More science-free word salad from a scientifically illiterate loon. What new data, and what are you suggesting it has changed? I must have asked this a dozen times, and all we get in return is more science-free word salad, and references to articles that you fail to understand.

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