APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

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APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by APOD Robot » Mon Dec 02, 2019 5:09 am

[img]https://apod.nasa.gov/apod/calendar/S_191202.jpg[/img] Mercury Crosses a Quiet Sun

Explanation: What's that black dot crossing the Sun? The planet Mercury. Mercury usually passes over or under the Sun, as seen from Earth, but last month the Solar System's innermost planet appeared to go just about straight across the middle. Although witnessed by planet admirers across the globe, a particularly clear view was captured by the Solar Dynamics Observatory (SDO) in Earth orbit. The featured video was captured by the SDO's HMI instrument in a broad range of visible light, and compresses the 5 1/2 hour transit into about 13 seconds. The background Sun was unusually quiet -- even for being near Solar Minimum -- and showed no sunspots. The next solar transit by Mercury will occur in 2032.

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DL MARTIN

Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by DL MARTIN » Mon Dec 02, 2019 6:58 am

Why were there ejections in the Nov. 14/19 APOD and not Dec. 2/19?

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by madtom1999 » Mon Dec 02, 2019 8:36 am

Why does it always seem to skip and hop across the sun? Is it just lost images?

heehaw

Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by heehaw » Mon Dec 02, 2019 10:37 am

How do I download a copy of that nice movie?

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by Boomer12k » Mon Dec 02, 2019 11:09 am

Awesome... and the music makes it dramatic...
A one billionth Solar Eclipse by Mercury...

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by orin stepanek » Mon Dec 02, 2019 1:39 pm

:lol2: Kinda like a mite crawling across an orange! :lol2:
Orin

Smile today; tomorrow's another day!

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Huffaker news

Post by neufer » Mon Dec 02, 2019 2:05 pm

orin stepanek wrote:
Mon Dec 02, 2019 1:39 pm

:lol2: Kinda like a mite crawling across an orange! :lol2:
https://en.wikipedia.org/wiki/Huffaker%27s_mite_experiment wrote:
<<In 1958, Carl Barton Huffaker, an ecologist and agricultural entomologist at the University of California, Berkeley, did a series of experiments with predatory and herbivorous mite species to investigate predator–prey population dynamics. In these experiments, he created model universes with arrays of rubber balls and oranges (food for the herbivorous mites) on trays and then introduced the predator and prey mite species in various permutations. Huffaker’s experimental universes showed that while under many circumstances predator–prey interactions will lead to extinction of both populations, interactions of spatial heterogeneity, dispersal ability of predator and prey species, and distribution of food sources can create an environment in which predator and prey species can coexist. The distribution of one prey species placed on each of 120 oranges, the impediments to predator movement created by the petroleum jelly divisions between sections of oranges, and the dispersal aid of wooden sticks for the prey species, all worked together to create a spatially heterogeneous environment in which both the predator and prey species survived for three population cycles. Huffaker ultimately concluded that, with added spatial heterogeneity, these mite populations could have continued to oscillate beyond three cycles. Looking forward, Huffaker noted the importance of understanding these concepts with respect to understanding the impact of monocultures (i.e. low spatial heterogeneity) in industrial agriculture on biodiversity.>>
Art Neuendorffer

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by Chris Peterson » Mon Dec 02, 2019 2:16 pm

DL MARTIN wrote:
Mon Dec 02, 2019 6:58 am
Why were there ejections in the Nov. 14/19 APOD and not Dec. 2/19?
The earlier APOD was imaged through a narrowband hydrogen-alpha filter. Today's was imaged in white light, which completely overpowers any prominences.
Chris

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“all the animals and birds were terrified”

Post by neufer » Mon Dec 02, 2019 2:26 pm

Boomer12k wrote:
Mon Dec 02, 2019 11:09 am

Awesome... and the music makes it dramatic...

A one billionth Solar Eclipse by Mercury...
https://www.nationalgeographic.com/news/2017/08/animals-react-total-solar-eclipse-august-space-science/ wrote:
Surprising Ways Animals React to Solar Eclipses
By Andrew Fazekas : Nat Geo August 14, 2017

<<Reports of unusual animal reactions to solar eclipses date back centuries. One of the earliest stories comes from Italian monk Ristoro d'Arezzo, who described what happened during a total eclipse on June 3, 1239. As the sun disappeared and the sky turned dark, “all the animals and birds were terrified; and the wild beasts could easily be caught,” he wrote.

During an eclipse seen in Portugal on August 21, 1560, astronomer Christoph Clavius wrote that during totality, “stars appeared in the sky and (marvellous to behold) the birds fell down from the sky to the ground in terror of such horrid darkness.”

Modern astronomers and eclipse chasers have also reported wild and domestic animals noticeably reacting to eclipses: Dairy cows return to the barn, crickets begin chirping, birds either go to roost or become more active, and whales breach in the seas. Veteran eclipse-chaser Peter den Hartog traveled to Hungary in 1999 to experience totality, and he remembers seeing various species of birds and bats suddenly appear during totality. “[Was it because of] the light intensity, or the flies and mosquitoes that came out … I'm not sure, but I‘ve definitely experienced more activity during eclipses,” Hartog says.

Eclipse-chaser and author Dave Balch was in Kona, Hawaii, for the 1991 total eclipse and noticed excited activity among the birds along the pier during the partial phases before and after totality. “We could hardly hear each other talk! Then came totality – not a sound. It was deathly quiet. The difference between the noise levels before and during totality was stunning.”

And eclipse-chaser Tora Greve was on an expedition to Zambia in 2001 when she noticed that, just as the sun disappeared, frogs began making sounds and raptors stopped circling, possibly due to the change in thermals as the air cooled. Around the water hole where she was standing, she says, giraffes “started running about during the whole totality. When the sun came back, they stopped and began grazing the trees again.”>>
Art Neuendorffer

DL MARTIN

Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by DL MARTIN » Mon Dec 02, 2019 4:01 pm

If, as Chris Peterson asserts, a different filter was used to rule out sun spots, then how authentic is the claim that the sun is in a particularly quiet period. how does the casual observer know what's real or photo shopped?

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by Chris Peterson » Mon Dec 02, 2019 4:09 pm

DL MARTIN wrote:
Mon Dec 02, 2019 4:01 pm
If, as Chris Peterson asserts, a different filter was used to rule out sun spots, then how authentic is the claim that the sun is in a particularly quiet period. how does the casual observer know what's real or photo shopped?
We know the Sun is quiet because there are no sunspots. That's pretty much what defines "quiet". Sunspots are visible in white light and Ha.

And why should anybody assume that either image is "photoshopped"? There are thousands of similar images out there, all of which look similar. None of the images show anything extraordinary.

(Of course, the first image is processed through a tool like Photoshop. Nearly all images are. But that doesn't mean it isn't an accurate depiction of the event.) The video is post processed, as well.
Chris

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by MarkBour » Mon Dec 02, 2019 4:47 pm

I think this video could be used as a "progress bar".
Mark Goldfain

DL MARTIN

Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by DL MARTIN » Mon Dec 02, 2019 4:49 pm

I wish to commend Chris Peterson for caring about his profession. I used to have a job in surgery where if I couldn't explain and defend what I was doing to the uninitiated observer then i shouldn't be working. Chris does that and as a non astronomer I appreciate his effort.
The reason I ask questions is because I care about science. When I sense (in my naivete) that something doesn't add up, I value someone clarifying matters.

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by neufer » Mon Dec 02, 2019 6:26 pm

DL MARTIN wrote:
Mon Dec 02, 2019 4:49 pm

I wish to commend Chris Peterson for caring about his profession.
And...what do you think is Chris Peterson's profession :?:
Art Neuendorffer

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Re: APOD: Mercury Crosses a Quiet Sun (2019 Dec 02)

Post by MarkBour » Mon Dec 02, 2019 11:00 pm

DL MARTIN wrote:
Mon Dec 02, 2019 4:49 pm
I wish to commend Chris Peterson ...
I also appreciate the many things that Chris has taught me about astronomy through this forum.
Mark Goldfain