APOD: Comet CG Evaporates (2020 Jan 27)

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APOD: Comet CG Evaporates (2020 Jan 27)

Post by APOD Robot » Mon Jan 27, 2020 5:17 am

Image Comet CG Evaporates

Explanation: Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. One of the best images of emerging jets is shown in the featured picture, taken in 2015 by ESA's robotic Rosetta spacecraft that orbited Comet 67P/Churyumov-Gerasimenko (Comet CG) from 2014 to 2016. The picture shows plumes of gas and dust escaping numerous places from Comet CG's nucleus as it neared the Sun and heated up. The comet has two prominent lobes, the larger one spanning about 4 kilometers, and a smaller 2.5-kilometer lobe connected by a narrow neck. Analyses indicate that evaporation must be taking place well inside the comet's surface to create the jets of dust and ice that we see emitted through the surface. Comet CG (also known as Comet 67P) loses in jets about a meter of radius during each of its 6.44-year orbits around the Sun, a rate at which will completely destroy the comet in only thousands of years. In 2016, Rosetta's mission ended with a controlled impact onto Comet CG's surface.

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Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by neufer » Mon Jan 27, 2020 2:09 pm

https://en.wikipedia.org/wiki/486958_Arrokoth wrote:

<<486958 Arrokoth (provisional designation 2014 MU69) is a trans-Neptunian object located in the Kuiper belt. It is a contact binary 36 km long, composed of two planetesimals 22 km and 15 km across (nicknamed "Ultima" and "Thule") that are joined along their major axes. Ultima, which is flatter than Thule, appears to be an aggregate of 8 or so smaller units, each approximately 5 km across, that fused together before Ultima and Thule came into contact. Because there have been few to no disruptive impacts on Arrokoth since it formed, the details of its formation have been preserved.

Topography variations at the limb of Arrokoth suggest that its interior is likely composed of mechanically strong material consisting of mostly amorphous water ice and rocky material. Trace amounts of methane and other volatile gases in the form of vapors may be also present in Arrokoth's interior, trapped in water ice. Under the assumption that Arrokoth has a low comet-like density of around 0.5 g/cm3, its internal structure is expected to be porous, as volatile gases trapped in Arrokoth's interior are thought to escape from the interior to the surface. Assuming that Arrokoth may have an internal heat source caused by the radioactive decay of radionuclides, the trapped volatile gases inside Arrokoth would migrate outward and escape from the surface, similarly to the scenario of outgassing of comets. The escaped gases may subsequently freeze and deposit on Arrokoth's surface, and could possibly account for the presence of ices and tholins on its surface.>>
Art Neuendorffer

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Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by orin stepanek » Mon Jan 27, 2020 2:10 pm

:shock: I think it kinda looks as though it is made of paper mache
or plaster of paris! :mrgreen:
I don't think this comet is one of the better tail makers; but
that is my own humble opinion!
It is kind of weird shaped; but that's my opinion also!

Comet67P_Rosetta_1024.jpg
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Orin

Smile today; tomorrow's another day!

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Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by sillyworm 2 » Mon Jan 27, 2020 2:28 pm

Definitely marzipan.

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Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by neufer » Mon Jan 27, 2020 3:44 pm

sillyworm 2 wrote:
Mon Jan 27, 2020 2:28 pm

Definitely marzipan.
https://en.wikipedia.org/wiki/Comet#Nucleus wrote:
<<The surface of the nucleus is generally dry, dusty or rocky, suggesting that the ices are hidden beneath a surface crust several metres thick. In addition to the gases already mentioned, the nuclei contain a variety of organic compounds, which may include methanol, hydrogen cyanide, formaldehyde, ethanol, ethane, and perhaps more complex molecules such as long-chain hydrocarbons and amino acids.>>
https://en.wikipedia.org/wiki/Marzipan wrote:
<<Marzipan is a confection consisting primarily of sugar or honey and almond meal (ground almonds), sometimes augmented with almond oil or extract. Sources establish the origin of marzipan in China, from where the recipe moved on to the Middle East and then to Europe through Al-Andalus. To produce marzipan, raw almonds are cleaned "by sieving, air elutriation, and other electronic or mechanical devices", then immersed in water with a temperature just below the boiling point for about five minutes, in a process known as blanching. This loosens the almonds' skin, which is removed by passing the almonds through rubber-covered rotating cylinders. This process reduces hydrogen cyanide (HCN) concentration and increases water content.>>
https://en.wikipedia.org/wiki/Almond#Amygdalin_and_cyanide wrote:
<<Bitter almonds may yield 4–9 mg of hydrogen cyanide (HCN) per almond and contain 42 times higher amounts of cyanide than the trace levels found in sweet almonds. The origin of cyanide content in bitter almonds is via the enzymatic hydrolysis of amygdalin. Extract of bitter almond was once used medicinally but even in small doses, effects are severe or lethal, especially in children for whom consuming 5–10 bitter almonds may be fatal.>>
https://en.wikipedia.org/wiki/Halley%27s_Comet wrote:
<<The 1910 approach of Halley's Comet was the first approach of which photographs exist, and the first for which spectroscopic data were obtained. Furthermore, the comet made a relatively close approach of 0.15 AU, making it a spectacular sight. Indeed, on 19 May, Earth actually passed through the tail of the comet. One of the substances discovered in the tail by spectroscopic analysis was the toxic gas cyanogen [(CN)2], which led astronomer Camille Flammarion to claim that, when Earth passed through the tail, the gas "would impregnate the atmosphere and possibly snuff out all life on the planet." His pronouncement led to panicked buying of gas masks and quack "anti-comet pills" and "anti-comet umbrellas" by the public.

The comet added to the unrest in China on the eve of the Xinhai Revolution that would end the last dynasty in 1911. As James Hutson, a missionary in Sichuan Province at the time, recorded: "The people believe that it indicates calamity such as war, fire, pestilence, and a change of dynasty. In some places on certain days the doors were unopened for half a day, no water was carried and many did not even drink water as it was rumoured that pestilential vapour was being poured down upon the earth from the comet.">>
Art Neuendorffer

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Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by Ann » Mon Jan 27, 2020 4:24 pm

neufer wrote:
Mon Jan 27, 2020 3:44 pm
sillyworm 2 wrote:
Mon Jan 27, 2020 2:28 pm

Definitely marzipan.
https://en.wikipedia.org/wiki/Comet#Nucleus wrote:
<<The surface of the nucleus is generally dry, dusty or rocky, suggesting that the ices are hidden beneath a surface crust several metres thick. In addition to the gases already mentioned, the nuclei contain a variety of organic compounds, which may include methanol, hydrogen cyanide, formaldehyde, ethanol, ethane, and perhaps more complex molecules such as long-chain hydrocarbons and amino acids.>>
Sugar Molecule. Art print by SafeTfun.
Bounty™ Almond Tree.




















Well, I guess it should be theoretically possible to find a sugar molecule in at least one comet somewhere in space. But extraterrestrial almonds are in all likelihood impossible to come by.


https://en.wikipedia.org/wiki/Marzipan wrote:
<<Marzipan is a confection consisting primarily of sugar or honey and almond meal (ground almonds), sometimes augmented with almond oil or extract. Sources establish the origin of marzipan in China, from where the recipe moved on to the Middle East and then to Europe through Al-Andalus. To produce marzipan, raw almonds are cleaned "by sieving, air elutriation, and other electronic or mechanical devices", then immersed in water with a temperature just below the boiling point for about five minutes, in a process known as blanching. This loosens the almonds' skin, which is removed by passing the almonds through rubber-covered rotating cylinders. This process reduces hydrogen cyanide (HCN) concentration and increases water content.>>
https://en.wikipedia.org/wiki/Almond#Amygdalin_and_cyanide wrote:
<<Bitter almonds may yield 4–9 mg of hydrogen cyanide (HCN) per almond and contain 42 times higher amounts of cyanide than the trace levels found in sweet almonds. The origin of cyanide content in bitter almonds is via the enzymatic hydrolysis of amygdalin. Extract of bitter almond was once used medicinally but even in small doses, effects are severe or lethal, especially in children for whom consuming 5–10 bitter almonds may be fatal.>>
Click to play embedded YouTube video.
Deathintheirfood.blogspot.com (or more precisely Roald Dahl) wrote:

Will you have another cup of tea?” “No, thank you,” Billy said. The tea tasted faintly of bitter almonds, and he didn’t much care for it."
https://en.wikipedia.org/wiki/Halley%27s_Comet wrote:
<<The 1910 approach of Halley's Comet was the first approach of which photographs exist, and the first for which spectroscopic data were obtained. Furthermore, the comet made a relatively close approach of 0.15 AU, making it a spectacular sight. Indeed, on 19 May, Earth actually passed through the tail of the comet. One of the substances discovered in the tail by spectroscopic analysis was the toxic gas cyanogen [(CN)2], which led astronomer Camille Flammarion to claim that, when Earth passed through the tail, the gas "would impregnate the atmosphere and possibly snuff out all life on the planet." His pronouncement led to panicked buying of gas masks and quack "anti-comet pills" and "anti-comet umbrellas" by the public.
The comet added to the unrest in China on the eve of the Xinhai Revolution that would end the last dynasty in 1911. As James Hutson, a missionary in Sichuan Province at the time, recorded: "The people believe that it indicates calamity such as war, fire, pestilence, and a change of dynasty. In some places on certain days the doors were unopened for half a day, no water was carried and many did not even drink water as it was rumoured that pestilential vapour was being poured down upon the earth from the comet.">>



Cometophobia: A part of the Bayeux Tapestry
and the horrifying appearance of Comet Halley in 1066.
Corona virus fear in China and elsewhere.
Uploaded by Channel 4 News, 22 jan. 2020.
Color Commentator

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Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by neufer » Mon Jan 27, 2020 4:53 pm

https://en.wikipedia.org/wiki/Cyanide#Interstellar_medium wrote:
<<A cyanide is a chemical compound that contains the group C≡N. Known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. The word is derived from the Greek kyanos, meaning dark blue, as a result of its being first obtained by the heating of the pigment known as Prussian blue. The cyanide radical ·CN has been identified in interstellar space. The cyanide radical (called cyanogen) is used to measure the temperature of interstellar gas clouds.

In inorganic cyanides, the cyanide group is present as the anion CN−. Salts such as sodium cyanide and potassium cyanide are highly toxic. Hydrocyanic acid, also known as hydrogen cyanide, or HCN, is a highly volatile liquid that is produced on a large scale industrially. Organic cyanides are usually called nitriles. In nitriles, the CN group is linked by a covalent bond to carbon. Some nitriles, which occur naturally as cyanohydrins, release hydrogen cyanide.

Cyanides are produced by certain bacteria, fungi, and algae and are found in a number of plants. Cyanides are found in substantial amounts in certain seeds and fruit stones, e.g., those of bitter almonds, apricots, apples, and peaches. In plants, cyanides are usually bound to sugar molecules in the form of cyanogenic glycosides and defend the plant against herbivores. The Madagascar bamboo Cathariostachys madagascariensis produces cyanide as a deterrent to grazing.

Hydrogen cyanide is produced by the combustion or pyrolysis of certain materials under oxygen-deficient conditions. For example, it can be detected in the exhaust of internal combustion engines and tobacco smoke. Certain plastics, especially those derived from acrylonitrile, release hydrogen cyanide when heated or burnt. Cyanide poisoning is relatively common following breathing in smoke from a house fire. Other potential routes of exposure include workplaces involved in metal polishing, certain insecticides, and certain seeds such as those of apples and apricots. Cyanide ions interfere with cellular respiration, resulting in the body's tissues being unable to use oxygen.>>
Art Neuendorffer

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Almond Joy?

Post by neufer » Mon Jan 27, 2020 5:14 pm

https://en.wikipedia.org/wiki/Amygdala wrote:


<<The amygdala (Latin from Greek, ἀμυγδαλή, 'almond') is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing of memory, decision-making and emotional responses. In one study, electrical stimulations of the right amygdala induced negative emotions, especially fear and sadness. In contrast, stimulation of the left amygdala was able to induce either pleasant (happiness) or unpleasant (fear, anxiety, sadness) emotions. Other evidence suggests that the left amygdala plays a role in the brain's reward system. The right and left portions of the amygdala have independent memory systems, but work together to store, encode, and interpret emotion.

The right hemisphere is also linked to declarative memory, which consists of facts and information from previously experienced events and must be consciously recalled. It also plays a significant role in the retention of episodic memory. Episodic memory consists of the autobiographical aspects of memory, permitting recall of emotional and sensory experience of an event. This type of memory does not require conscious recall. The right amygdala plays a role in the association of time and places with emotional properties.

The amygdala is one of the best-understood brain regions with regard to differences between the sexes. The amygdala is larger in males than females in children ages 7–11, in adult humans, and in adult rats. Functional and structural differences between male and female amygdalae have been observed. Subjects' amygdala activation was observed when watching a horror film and subliminal stimuli. Enhanced memory for the film was related to enhanced activity of the left, but not the right, amygdala in women, whereas it was related to enhanced activity of the right, but not the left, amygdala in men. One study found evidence that on average, women tend to retain stronger memories for emotional events than men.

The right amygdala is also linked with taking action as well as being linked to negative emotions, which may help explain why males tend to respond to emotionally stressful stimuli physically. The left amygdala allows for the recall of details, but it also results in more thought rather than action in response to emotionally stressful stimuli, which may explain the absence of physical response in women.>>
Art Neuendorffer

sillyworm 2

Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by sillyworm 2 » Tue Jan 28, 2020 12:23 am

SO MUCH interesting information!

Deathfleer

Re: APOD: Comet CG Evaporates (2020 Jan 27)

Post by Deathfleer » Tue Jan 28, 2020 12:59 am

Just like particles above a bon fire, as they near the fire, they fly away, pushed by the gas.