APOD: AR 3664: Giant Sunspot Group (2024 May 11)

[APOD Robot]

AR 3664: Giant Sunspot Group

Explanation: Right now, one of the largest sunspot groups in recent history is crossing the Sun. Active Region 3664 is not only big -- it's violent, throwing off clouds of particles into the Solar System. Some of these CMEs are already impacting the Earth, and others might follow. At the extreme, these solar storms could cause some Earth-orbiting satellites to malfunction, the Earth's atmosphere to slightly distort, and electrical power grids to surge. When impacting Earth's upper atmosphere, these particles can produce beautiful auroras, with some auroras already being reported unusually far south. Pictured here, AR3664 and its dark sunspots were captured yesterday in visible light from Rome, Italy. The AR3664 sunspot group is so large that it is visible just with glasses designed to view last month's total solar eclipse. This weekend, skygazing enthusiasts will be keenly watching the night skies all over the globe for bright and unusual auroras.

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[Ann]

AR 3664: Giant Sunspot Group. Image Credit & Copyright: Franco Fantasia & Guiseppe Conzo (Gruppo Astrofili Palidoro)

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So this thing is really big. And active, too.

It always bothered me that sunspots are dark because they are cooler than their surroundings, and yet they are so active. Why would cooler things be more active than hotter things?

Then again, the sunspots are about the same temperature as a red dwarf star (or at least about the same temperature as orange dwarfs of spectral class K), and red dwarfs (at least those of spectral class M) are known to be extremely active and spit stuff into the surroundings:

An artist’s impression of a flaring red dwarf and its exoplanet. Credit: AIP / J. Fohlmeister

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The red dwarf in the illustration appears to be peppered with dark spots near its poles, and the flares seem to be coming from the same general regions. Are red dwarfs particularly rich in sunspots, and is that why they are so active? I could google, but I'm too lazy.


But I found something else when I googled, namely a sunspots as seen in different wavelengths. And it is hugely interesting to compare a sunspot in visible light and in very near ultraviolet light:

A sunspot seen in the visible G band, 4305 Å.

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The same sunspot in the very near ultraviolet Ca II H line, 3968 Å.

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The point here is that sunspots are indeed darker and cooler than their surroundings, but they are also brighter and hotter than the rest of the photosphere! But we don't see the bright parts of the sunspots, because our eyes are quite insensitive to these very near ultraviolet wavelengths.

And it's all caused by magnetism. Sorry! I'll leave that to the rest of you to discuss.

APOD Robot wrote:

When impacting Earth's upper atmosphere, these particles can produce beautiful auroras, with some auroras already being reported unusually far south.

Yes. Last night, auroras could be seen over my hometown of Malmö.

An aurora over my hometown of Malmö, on the night between the 10th and the 11th of May, 2024. Credit: Gunilla Hartsmar

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Did I see this aurora? Heck no. I was fast asleep.

Ann

[AVAO]

AR 3664: Giant Sunspot Group

Explanation: Right now, one of the largest sunspot groups in recent history is crossing the Sun. Active Region 3664 is not only big -- it's violent, throwing off clouds of particles into the Solar System. Some of these CMEs are already impacting the Earth, and others might follow. At the extreme, these solar storms could cause some Earth-orbiting satellites to malfunction, the Earth's atmosphere to slightly distort, and electrical power grids to surge. When impacting Earth's upper atmosphere, these particles can produce beautiful auroras, with some auroras already being reported unusually far south. Pictured here, AR3664 and its dark sunspots were captured yesterday in visible light from Rome, Italy. The AR3664 sunspot group is so large that it is visible just with glasses designed to view last month's total solar eclipse. This weekend, skygazing enthusiasts will be keenly watching the night skies all over the globe for and unusual auroras.

<< Previous APOD

This Day in APOD

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I have never experienced something like that. Last night the Northern Lights were visible across the sky throughout Switzerland. Crazy! ( https://www.watson.ch/schweiz/wissen/39 ... chweiz-aus )

Click to view full size image

Northern lights over the Lago di Lugano, located in the south (Ticino) of Switzerland. (10.05.2024 - 11.30 pm MEZ) jac berne (flickr)

[FLPhotoCatcher]

Here's a photo I took looking to the west-northwest, with the crescent moon and earthshine visible. A lightning bug decided to photobomb the aurora.
This was taken in middle Tennessee, USA, where there is no light pollution.

[Ann]

Malmö is heavily light-polluted, which is why it's so remarkable that auroras could be seen in our skies. In more rural areas in the southernmost region of Sweden, auroras looked a lot more impressive.

An aurora in a rural setting some 60 kilometers (40 miles) north of Malmö. Note the 'Horsehead' tree. Photo: Lasse Flygare, I guess.

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Ann

[varadinagypal]

Is this image, its quality and the gesture to publish it, a huge joke? From time to time APOD editions pop into my view, last time I left some abrasive comments was for the photoshoped solar eclipse-moon-something. I literally shoot better (read: much better, link below to our forum) images during a lunch break, at the office window, sipping coffee. What the phosphorus is this pixel mesh? https://www.asztrofoto.hu/galeria_image/1715358058

[Roy]

Earth is sweeping up “particles” - charged, by the way - from solar flares. What charged particle? Electrons & protons - electricity. Now we get to see if it sis another Carrington event. My thought is: probably not, because there are a lot more wires and a lot more grounds than there were in 1859,to sweep up the current and ground it. IMHO.

[Chris Peterson]

Earth is sweeping up “particles” - charged, by the way - from solar flares. What charged particle? Electrons & protons - electricity. Now we get to see if it sis another Carrington event. My thought is: probably not, because there are a lot more wires and a lot more grounds than there were in 1859,to sweep up the current and ground it. IMHO.

A Carrington event would be much more severe today than it was in 1859, precisely because there are more paths for current to flow, and much more sensitive devices attached to those paths. Fortunately none of the CMEs ejected by this sunspot group have been remotely close in strength to the ones ejected in 1859 from a similar sunspot group. But we're not quite out of the woods yet.

[Michael Teoh]

Is this image, its quality and the gesture to publish it, a huge joke?

Maybe celebrating late April Fool?

[johnnydeep]

Sunspot groups remind me of random Life patterns (as in Conway's cellular automaton "Game of Life"). Here's an illustrative example I just created with the very excellent "Golly" app:

And hey, the Sun's atmosphere is even partitioned into "cells" just like the universe that Life is iterated on! Quite a pleasing correspondence if I do say so myself. From https://www.esa.int/ESA_Multimedia/Imag ... _by_Hinode

Hinode's Solar Optical Telescope (SOT) is the first space-borne instrument to measure the strength and direction of the sun's magnetic field in the sun's low atmosphere, also called the photosphere. This image from the Solar Optical Telescope shows a greatly magnified portion of the solar surface. Energy from below the surface of the sun is transported by convection and results in the convection cells, or granulation, seen in this image. The lighter areas reveal where gases are rising from below, while the darker ' intergranular lanes' reveal where cooler gases are sinking back down.

Click to view full size image

[Ann]

Sunspot groups remind me of random Life patterns (as in Conway's cellular automaton "Game of Life"). Here's an illustrative example I just created with the very excellent "Golly" app:

Click to view full size image

But the location of sunspots on the Sun is not random.

Where sunspots are found on the Sun. Credit: Soumyadeep Mukherjee

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Ann

[johnnydeep]

Sunspot groups remind me of random Life patterns (as in Conway's cellular automaton "Game of Life"). Here's an illustrative example I just created with the very excellent "Golly" app:

Click to view full size image

But the location of sunspots on the Sun is not random.

Where sunspots are found on the Sun. Credit: Soumyadeep Mukherjee

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Ann

That's fine since many Life patterns result in highly repetitious large scale structure! See, this metaphor just keeps getting more apt!

EDIT: Here's a so-called "dirty" "puffer train" pattern, that repeats, but not identically each time. From https://en.wikipedia.org/wiki/Puffer_train

[Christian G.]

Are red dwarfs particularly rich in sunspots, and is that why they are so active?

They are more than rich I think, instead of flares occurring as local phenomena as on the surface of the Sun, with some M dwarfs it's the entire star that flares! I remember a funny excerpt from James Kaler's Extreme Stars where he describes a person sun-bathing or dwarf-M-bathing on a beach and suddenly the sun gets ten times brighter in minutes!

[VictorBorun]

the location of sunspots on the Sun is not random.

Where sunspots are found on the Sun. Credit: Soumyadeep Mukherjee

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Ann

seems rather like one of those 100 days of sunspots infographics than a snapshot portrait of so regular a pattern of so many a groups of Sun's spots

[Chris Peterson]

Pretty good here in central Colorado, 38°N, despite it being pretty cloudy.

This is an allsky video from late twilight to 1:30am when it completely clouded over.



Last image below was taken pointing very high, with the Big Dipper in the frame.
_

[johnnydeep]

Pretty good here in central Colorado, 38°N, despite it being pretty cloudy.

This is an allsky video from late twilight to 1:30am when it completely clouded over.



Last image below was taken pointing very high, with the Big Dipper in the frame.
_
E7_48521p.jpg
E7_48527p.jpg
E7_48532p.jpg

Ok, where are the sunspots?

[Chris Peterson]

Pretty good here in central Colorado, 38°N, despite it being pretty cloudy.

This is an allsky video from late twilight to 1:30am when it completely clouded over.



Last image below was taken pointing very high, with the Big Dipper in the frame.
_
E7_48521p.jpg
E7_48527p.jpg
E7_48532p.jpg

Ok, where are the sunspots?

Wrong question. Cause and effect. Where were the sunspots a couple of days ago? That's what mattered!

[johnnydeep]

Pretty good here in central Colorado, 38°N, despite it being pretty cloudy.

This is an allsky video from late twilight to 1:30am when it completely clouded over.



Last image below was taken pointing very high, with the Big Dipper in the frame.
_
E7_48521p.jpg
E7_48527p.jpg
E7_48532p.jpg

Ok, where are the sunspots?

Wrong question. Cause and effect. Where were the sunspots a couple of days ago? That's what mattered!

And where were they? Is it ever possible to link a specific sunspot group with an aurora?

[Chris Peterson]

Ok, where are the sunspots?

Wrong question. Cause and effect. Where were the sunspots a couple of days ago? That's what mattered!

And where were they? Is it ever possible to link a specific sunspot group with an aurora?

The four CMEs in the last days, and the new one today, all came from this group, and are responsible for the current auroral activity.

[johnnydeep]

Wrong question. Cause and effect. Where were the sunspots a couple of days ago? That's what mattered!

And where were they? Is it ever possible to link a specific sunspot group with an aurora?

The four CMEs in the last days, and the new one today, all came from this group, and are responsible for the current auroral activity.

Ok. Is the cause and effect indisputable? I guess so simply due to travel time from the Sun and the extreme improbability of it NOT being so.

[Chris Peterson]

And where were they? Is it ever possible to link a specific sunspot group with an aurora?

The four CMEs in the last days, and the new one today, all came from this group, and are responsible for the current auroral activity.

Ok. Is the cause and effect indisputable? I guess so simply due to travel time from the Sun and the extreme improbability of it NOT being so.

The flares and ejections are observed and measured by spacecraft that constantly monitor the Sun. Every CME is noted and its characteristics recorded, including whether it is Earth-directed. So yes... most auroral activity (and all major events like this one) are reliably connected to specific, identified events on the Sun.

[varadinagypal]

The flares and ejections are observed and measured by spacecraft that constantly monitor the Sun. Every CME is noted and its characteristics recorded, including whether it is Earth-directed. So yes... most auroral activity (and all major events like this one) are reliably connected to specific, identified events on the Sun.

I may have just the right flare (or... the other one) in a calcium K movie.

Anyways, APOD's quality and selection criteria have become laughing stock, and I don't normally follow it anymore, but social media, from time to time, throws stuff up.

[johnnydeep]

The four CMEs in the last days, and the new one today, all came from this group, and are responsible for the current auroral activity.

Ok. Is the cause and effect indisputable? I guess so simply due to travel time from the Sun and the extreme improbability of it NOT being so.

The flares and ejections are observed and measured by spacecraft that constantly monitor the Sun. Every CME is noted and its characteristics recorded, including whether it is Earth-directed. So yes... most auroral activity (and all major events like this one) are reliably connected to specific, identified events on the Sun.

[johnnydeep]

Is this image, its quality and the gesture to publish it, a huge joke? From time to time APOD editions pop into my view, last time I left some abrasive comments was for the photoshoped solar eclipse-moon-something. I literally shoot better (read: much better, link below to our forum) images during a lunch break, at the office window, sipping coffee. What the phosphorus is this pixel mesh? https://www.asztrofoto.hu/galeria_image/1715358058

So, your image of this same sunspot group is indeed impressively detailed, and looks great to this rank amateur with little astro-photographical acumen, but what's your specific complaint about this particular APOD?

[Chris Peterson]

Is this image, its quality and the gesture to publish it, a huge joke? From time to time APOD editions pop into my view, last time I left some abrasive comments was for the photoshoped solar eclipse-moon-something. I literally shoot better (read: much better, link below to our forum) images during a lunch break, at the office window, sipping coffee. What the phosphorus is this pixel mesh? https://www.asztrofoto.hu/galeria_image/1715358058

So, your image of this same sunspot group is indeed impressively detailed, and looks great to this rank amateur with little astro-photographical acumen, but what's your specific complaint about this particular APOD?

I have observed in the last few years an increasing number of what I'd call marginal quality images in comparison with better ones of the same objects. A lot of these come from... I don't know where. Not ones that have been submitted through the forum, as far as I can tell. I certainly wouldn't call this APOD a "joke" or denigrate it severely. It's an okay image. But there have been many sharper, better images of this sunspot group making the rounds, including ones submitted here. So I'd say that this wasn't the best choice to illustrate the point.