APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

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Expand view Topic review: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by VictorBorun » Sat Jul 03, 2021 6:59 am

De58te wrote: ↑Fri Jul 02, 2021 10:18 am Where did the APOD description mention the words deep and wormhole? I must have missed that. And I have always thought that when they mention an atmosphere is thick that they meant deep instead of wide. For example when geologists say the Vesuvius eruption covered Pompeii with a thick layer of ash, that they meant deep instead of wide. So if your quote said the sunspot is tens of kilometers thick, wouldn't that be deep?
Do you like to see a wormhole presentation of this sunspot? Here it is.
This 3D is as deep as wide, and is wrong.
There is in fact no external illumination leaving a hole dark here.
But there is a space for a debate, underneath the pancake of this sunspot.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by neufer » Sat Jul 03, 2021 3:55 am

Chris Peterson wrote: ↑Fri Jul 02, 2021 10:44 pm
neufer wrote: ↑Fri Jul 02, 2021 10:08 pm
Chris Peterson wrote: ↑Fri Jul 02, 2021 7:26 pm

Yes. Everything we see here is very nearly on a common surface,
with very little relief. Brightness is determined by temperature.
Moderate relief :?: :
  • Crater Lake (Oregon) is ~7,300 meters wide & ~350 meters (~5%) deep.
    A Sunspot 130,000 kilometers wide is about 4,000 kilometers (~3%) deep.
    The shallow Pacific Ocean is ~13,000 km wide and ~4 km (~0.03%) deep.
https://link.springer.com/article/10.1134%2FS0016793214070123 wrote:
The sunspot—shallow or deep?
Geomagnetism and Aeronomy volume 54, pages 915–919 (2014)
A. A. Solov’ev & E. A. Kirichek

Abstract: Two sunspot models are compared-shallow and deep. According to the former, a sunspot, as a region occupied by a strong regular field and comparatively cold plasma, penetrates into the solar convection zone to a shallow depth of about 4 Mm. This corresponds to both local seismology data and a series of compelling theoretical arguments. The deep model supposes that the sunspot magnetic field penetrates to the bottom of the convective zone, with the monotone increasing with depth without being turbulized, where it attains a strength of higher than 150 kG. It is shown that the deep model contradicts some basic concepts of solar physics and cannot be an alternative to the shallow sunspot model.
Moderate is probably an overstatement. Tiny is probably better.
Define "tiny" (in either absolute or relative terms).

Valles Marineris is ~7 km (= ~0.2% of Mars's radius) deep.
A sunspot is ~4,000 km (= ~0.6% of Sol's radius) deep.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by Chris Peterson » Fri Jul 02, 2021 10:44 pm

neufer wrote: ↑Fri Jul 02, 2021 10:08 pm
Chris Peterson wrote: ↑Fri Jul 02, 2021 7:26 pm
dBerch wrote: ↑Fri Jul 02, 2021 6:11 pm
In today's APOD of sunspots, you state " Found in solar active regions, sunspots look dark only because they are slightly cooler"

I'm sorry, but it just looks like hole to me. Am I mistaken?
Yes. Everything we see here is very nearly on a common surface,
with very little relief. Brightness is determined by temperature.
Moderate relief :?: :
  • Crater Lake (Oregon) is ~7,300 meters wide & ~350 meters (~5%) deep.
    A Sunspot 130,000 kilometers wide is about 4,000 kilometers (~3%) deep.
    The shallow Pacific Ocean is ~13,000 km wide and ~4 km (~0.03%) deep.
https://link.springer.com/article/10.1134%2FS0016793214070123 wrote:
The sunspot—shallow or deep?
Geomagnetism and Aeronomy volume 54, pages 915–919 (2014)
A. A. Solov’ev & E. A. Kirichek

Abstract: Two sunspot models are compared-shallow and deep. According to the former, a sunspot, as a region occupied by a strong regular field and comparatively cold plasma, penetrates into the solar convection zone to a shallow depth of about 4 Mm. This corresponds to both local seismology data and a series of compelling theoretical arguments. The deep model supposes that the sunspot magnetic field penetrates to the bottom of the convective zone, with the monotone increasing with depth without being turbulized, where it attains a strength of higher than 150 kG. It is shown that the deep model contradicts some basic concepts of solar physics and cannot be an alternative to the shallow sunspot model.
Moderate is probably an overstatement. Tiny is probably better.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by neufer » Fri Jul 02, 2021 10:08 pm

Chris Peterson wrote: ↑Fri Jul 02, 2021 7:26 pm
dBerch wrote: ↑Fri Jul 02, 2021 6:11 pm
In today's APOD of sunspots, you state " Found in solar active regions, sunspots look dark only because they are slightly cooler"

I'm sorry, but it just looks like hole to me. Am I mistaken?
Yes. Everything we see here is very nearly on a common surface,
with very little relief. Brightness is determined by temperature.
Moderate relief :?: :
  • Crater Lake (Oregon) is ~7,300 meters wide & ~350 meters (~5%) deep.
    A Sunspot 130,000 kilometers wide is about 4,000 kilometers (~3%) deep.
    The shallow Pacific Ocean is ~13,000 km wide and ~4 km (~0.03%) deep.
https://link.springer.com/article/10.1134%2FS0016793214070123 wrote:
The sunspot—shallow or deep?
Geomagnetism and Aeronomy volume 54, pages 915–919 (2014)
A. A. Solov’ev & E. A. Kirichek

Abstract: Two sunspot models are compared-shallow and deep. According to the former, a sunspot, as a region occupied by a strong regular field and comparatively cold plasma, penetrates into the solar convection zone to a shallow depth of about 4 Mm. This corresponds to both local seismology data and a series of compelling theoretical arguments. The deep model supposes that the sunspot magnetic field penetrates to the bottom of the convective zone, with the monotone increasing with depth without being turbulized, where it attains a strength of higher than 150 kG. It is shown that the deep model contradicts some basic concepts of solar physics and cannot be an alternative to the shallow sunspot model.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by BillBixby » Fri Jul 02, 2021 7:30 pm

dBerch wrote: ↑Fri Jul 02, 2021 6:11 pm In today's APOD of sunspots, you state " Found in solar active regions, sunspots look dark only because they are slightly cooler"

I'm sorry, but it just looks like hole to me. Am I mistaken?
I think it is something visible in a place where the spot would not be expected. Therefore an understanding of why and how is desired. Initially I was thinking of two holes in water connected beneath the water, like a tunnel. But such a thing would be both unexplainable and impossible. How does one explain the Chunnel from London to Paris? Moving away from the sun I decided to consider an ice cube in a tub of water. How did it get there and why. Through that idea away as being unnatural.
Something cold on a hot surface? Got it.
Looking at today’s APOD, I can relate to a pothole/mud-puddle on a winter day. Cold water with a piece of ice floating about in it. Not magnetic lines but a dynamic which puts this sunspot into a form I can understand.
Three cheers for today’s APOD and the scientists that brought it to me.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by Chris Peterson » Fri Jul 02, 2021 7:26 pm

dBerch wrote: ↑Fri Jul 02, 2021 6:11 pm In today's APOD of sunspots, you state " Found in solar active regions, sunspots look dark only because they are slightly cooler"

I'm sorry, but it just looks like hole to me. Am I mistaken?
Yes. Everything we see here is very nearly on a common surface, with very little relief. Brightness is determined by temperature.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by dBerch » Fri Jul 02, 2021 6:11 pm

In today's APOD of sunspots, you state " Found in solar active regions, sunspots look dark only because they are slightly cooler"

I'm sorry, but it just looks like hole to me. Am I mistaken?

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by neufer » Fri Jul 02, 2021 2:33 pm

Click to play embedded YouTube video.
Click to play embedded YouTube video.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by orin stepanek » Fri Jul 02, 2021 11:41 am

Ah; worked on you-tube now! :D

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by orin stepanek » Fri Jul 02, 2021 11:34 am

bystander wrote: ↑Fri Jul 02, 2021 11:11 am A
orin stepanek wrote: ↑Fri Jul 02, 2021 11:06 am Could not get the Magnetic fields video to work! Hmm! :shock:
Works for me. There is also a youtube link.
I get a voice and no picture! On the you-tube I get a picture and no voice! Weird! :shock: everything else works!

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by bystander » Fri Jul 02, 2021 11:11 am

A
orin stepanek wrote: ↑Fri Jul 02, 2021 11:06 am Could not get the Magnetic fields video to work! Hmm! :shock:
Works for me. There is also a youtube link.

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by orin stepanek » Fri Jul 02, 2021 11:06 am

AR2835_20210701_W2x.jpg
Could not get the Magnetic fields video to work! Hmm! :shock:

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by De58te » Fri Jul 02, 2021 10:18 am

Where did the APOD description mention the words deep and wormhole? I must have missed that. And I have always thought that when they mention an atmosphere is thick that they meant deep instead of wide. For example when geologists say the Vesuvius eruption covered Pompeii with a thick layer of ash, that they meant deep instead of wide. So if your quote said the sunspot is tens of kilometers thick, wouldn't that be deep?

Re: APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by VictorBorun » Fri Jul 02, 2021 5:53 am

The sunspot seems to be a deep wormhole.
In fact it is as flat as the bright hot grains all around.
Its strong (3000 gauss) magnetic field stops the flow that heats the grains from the Convection zone beneath.

A sunspot and a grain both have the same transparent atmosphere above and both are tens to hundreds of kilometers thick, and is slightly less opaque than air on Earth; myself I would call it "tens to hundreds of kilometers thin" remembering that grains are a thousand km wide and spots are 30,000 km wide.

So a sunspot is a thin thermo-insulating pancake floating on a hot sea of frying oil convection. No deep view here.

A magnetic thing must run deep though.

APOD: AR2835: Islands in the Photosphere (2021 Jul 02)

by APOD Robot » Fri Jul 02, 2021 4:05 am

Image AR2835: Islands in the Photosphere

Explanation: Awash in a sea of incandescent plasma and anchored in strong magnetic fields, sunspots are planet-sized dark islands in the solar photosphere, the bright surface of the Sun. Found in solar active regions, sunspots look dark only because they are slightly cooler though, with temperatures of about 4,000 kelvins compared to 6,000 kelvins for the surrounding solar surface. These sunspots lie in active region AR2835. The largest active region now crossing the Sun, AR2835 is captured in this sharp telescopic close-up from July 1 in a field of view that spans about 150,000 kilometers or over ten Earth diameters. With powerful magnetic fields, solar active regions are often responsible for solar flares and coronal mass ejections, storms which affect space weather near planet Earth.

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