APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

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APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby APOD Robot » Mon Nov 06, 2017 5:05 am

Image A Dust Jet from the Surface of Comet 67P

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. Last year, though, ESA's Rosetta spacecraft not only imaged a jet emerging from Comet 67P/Churyumov-Gerasimenko, but flew right through it. Featured is a telling picture showing a bright plume emerging from a small circular dip bounded on one side by a 10-meter high wall. Analyses of Rosetta data shows that the jet was composed of both dust and water-ice. The mundane terrain indicates that something likely happened far under the porous surface to create the plume. This image was taken last July, about two months before Rosetta's mission ended with a controlled impact onto Comet 67P's surface.

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby Boomer12k » Mon Nov 06, 2017 8:20 am

Good image...

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heehaw

Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby heehaw » Mon Nov 06, 2017 9:56 am

Wow. Seeing the surface of a comet! Pretty jet of tail-stuff! When I was born 77 years ago we knew so little about any solar system denizen. We thought Mercury's rotation period was the same as its orbital period. I remember heartbreak when I read in the Toronto Globe and Mail that radio astronomers had measured below the clouds of Venus and instead of the oceans, continents, and maybe dinosaurs we had all hoped for ... extremely high temperatures revealing Venus to be a fine candidate to be hell. What a disappointment! There will surely never ever be a manned visit to Venus! And Mars turned out to have so little water, and so much radiation, that I don't believe that it can ever be a new home for us. And the stars are still so very, very, far away....

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby neufer » Mon Nov 06, 2017 1:42 pm

.
    A wheezing old geyser choking on its own crud?
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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby neufer » Mon Nov 06, 2017 2:01 pm

heehaw wrote:
When I was born 77 years ago we knew so little about any solar system denizen. We thought Mercury's rotation period was the same as its orbital period. I remember heartbreak when I read in the Toronto Globe and Mail that radio astronomers had measured below the clouds of Venus and instead of the oceans, continents, and maybe dinosaurs we had all hoped for ...

SpaceX might even have been able to send you to a Dinosaur Park on Venus.
    What could go wrong :!:
heehaw wrote:
And Mars turned out to have so little water, and so much radiation, that I don't believe that it can ever be a new home for us.

And the Martians might even have been able to send their own tourists to Grover's Mill, New Jersey.
    What could go wrong :!:
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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby Fred the Cat » Mon Nov 06, 2017 2:14 pm

neufer wrote:.
    A wheezing old geyser choking on its own crud?

Or a sneezing geezer chock-full of its own crude? :yes:
Feynman's Felicity "Only ascertain as a cat box survivor"

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby Ann » Mon Nov 06, 2017 3:13 pm

I find the picture quite interesting.

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby saturno2 » Mon Nov 06, 2017 4:40 pm

Very interesting image
This geyser of dust and water-ice is very small,
the surface of the Comet is very big ( relative )

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby bystander » Mon Nov 06, 2017 4:49 pm

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby JohnD » Mon Nov 06, 2017 6:30 pm

Thanks for all the links as well, in particular the "mundane terrain" one that shows the precise area before the plume erupted.
Fascinating!
John

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby melrod » Mon Nov 06, 2017 7:36 pm

Pictures like this give me a sense of relatable place compared to the grandeur of a galaxy or wondrous enormity of a nebula.

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby MarkBour » Mon Nov 06, 2017 10:25 pm

heehaw wrote:... There will surely never ever be a manned visit to Venus! And Mars turned out to have so little water, and so much radiation, that I don't believe that it can ever be a new home for us. And the stars are still so very, very, far away ...

"Never ever?" I have hope! Or at least, if we never set foot on Venus, we still might learn to inhabit its atmosphere.

"A journey of a thousand miles begins with a single step."
-- Lao Tsu
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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby neufer » Mon Nov 06, 2017 11:03 pm

MarkBour wrote:
heehaw wrote:
... There will surely never ever be a manned visit to Venus! And Mars turned out to have so little water, and so much radiation, that I don't believe that it can ever be a new home for us. And the stars are still so very, very, far away ...

"Never ever?" I have hope! Or at least, if we never set foot on Venus, we still might learn to inhabit its atmosphere.

"A journey of a thousand miles begins with a single step."
-- Lao Tsu

    One need only take "a single step" outside in Beijing today
    to experience a simulated trip to Venus's atmosphere:
https://en.wikipedia.org/wiki/Atmosphere_of_Venus wrote:
<<Venusian clouds are thick and are composed mainly (75-96%) of sulfuric acid droplets. Venus's sulfuric acid rain never reaches the ground, but is evaporated by the heat before reaching the surface in a phenomenon known as virga. The sulfuric acid droplets can be highly electrically charged, and so they offer the potential for lightning. Venus' small induced magnetosphere provides negligible protection to the atmosphere against cosmic radiation. This radiation may result in cloud-to-cloud lightning discharges. Analysis of data from the Venera, Pioneer, and Magellan missions has found the chemicals hydrogen sulfide (H2S) and sulfur dioxide (SO2) together in the upper atmosphere, as well as carbonyl sulfide (OCS). In addition, one of the early Venera probes detected large amounts of toxic chlorine just below the Venusian cloud deck.>>
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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby Buddy » Tue Nov 07, 2017 1:02 am

melrod wrote:Pictures like this give me a sense of relatable place compared to the grandeur of a galaxy or wondrous enormity of a nebula.


Same here. I find the nebula and galaxy pictures interesting, but I like the pictures of solid bodies better.

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby Buddy » Tue Nov 07, 2017 1:08 am

heehaw wrote:Wow. Seeing the surface of a comet! Pretty jet of tail-stuff! When I was born 77 years ago we knew so little about any solar system denizen. We thought Mercury's rotation period was the same as its orbital period. I remember heartbreak when I read in the Toronto Globe and Mail that radio astronomers had measured below the clouds of Venus and instead of the oceans, continents, and maybe dinosaurs we had all hoped for ... extremely high temperatures revealing Venus to be a fine candidate to be hell. What a disappointment! There will surely never ever be a manned visit to Venus! And Mars turned out to have so little water, and so much radiation, that I don't believe that it can ever be a new home for us. And the stars are still so very, very, far away....


I remember reading somewhere that humans will never, ever venture to the stars, not now or in the next billion years. The reason, genetic sciences are advancing by leaps and bounds. The current state of GMO is just the tip of the iceberg. What will go to the stars might originate from humans, but will be so adapted to space travel as to be not in the same genus as us. Like the differences among the great apes.

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby MarkBour » Tue Nov 07, 2017 4:34 pm

Buddy wrote:I remember reading somewhere that humans will never, ever venture to the stars, not now or in the next billion years. The reason, genetic sciences are advancing by leaps and bounds. The current state of GMO is just the tip of the iceberg. What will go to the stars might originate from humans, but will be so adapted to space travel as to be not in the same genus as us. Like the differences among the great apes.

Robo sapiens, or astro sapiens. ... and that "species" may already exist.
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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby BDanielMayfield » Tue Nov 07, 2017 8:59 pm

neufer wrote:.
    A wheezing old geyser choking on its own crud?

:lol2:
"Happy are the peaceable ... "

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby BDanielMayfield » Tue Nov 07, 2017 9:09 pm

JohnD wrote:Thanks for all the links as well, in particular the "mundane terrain" one that shows the precise area before the plume erupted.
Fascinating!
John

Indeed. The depression surrounding the jet's vent reminds me of a volcanic caldera here on Earth.

Bruce
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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby Bird_Man » Thu Nov 09, 2017 4:23 pm

Fascinating image - much different than I expected the surface of a comet to look like.
I wonder if the circular structures to the left of the active vent are the sites of previous venting.

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Re: APOD: A Dust Jet from the Surface of Comet 67P (2017 Nov 06)

Postby neufer » Thu Nov 09, 2017 5:24 pm

Bird_Man wrote:
Fascinating image - much different than I expected the surface of a comet to look like.
I wonder if the circular structures to the left of the active vent are the sites of previous venting.
https://www.etymonline.com/word/vent wrote:
vent (v.) late 14c., "emit from a confined space," probably a shortening of aventer "expose oneself to the air" (c. 1300), from Old French eventer "let out, expose to air," from Vulgar Latin *exventare, from Latin ex "out" + ventus "wind" (see wind (n.1)). Sense of "express freely" first recorded 1590s. Sense of "divulge, publish" (1590s) is behind phrase vent one's spleen.

vent (n.) c. 1400, "anus," from Old French vent from verb eventer (see vent (v.)) and in part from Middle English aventer, from the French verb. Perhaps also merged with or influenced by Middle English fent "opening or slit in a the front of a garment (usually held closed with a brooch)," c. 1400, from Old French fente, from Latin findere "to split". Meaning "outlet for water," also "air hole, breathing hole" is from mid-15c.
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