APOD: A Large Tsunami Shock Wave on the Sun (2022 May 22)

[APOD Robot]

A Large Tsunami Shock Wave on the Sun

Explanation: Tsunamis this large don't happen on Earth. During 2006, a large solar flare from an Earth-sized sunspot produced a tsunami-type shock wave that was spectacular even for the Sun. Pictured here, the tsunami wave was captured moving out from active region AR 10930 by the Optical Solar Patrol Network (OSPAN) telescope in New Mexico, USA. The resulting shock wave, known technically as a Moreton wave, compressed and heated up gasses including hydrogen in the photosphere of the Sun, causing a momentarily brighter glow. The featured image was taken in a very specific red color emitted exclusively by hydrogen gas. The rampaging tsunami took out some active filaments on the Sun, although many re-established themselves later. The solar tsunami spread at nearly one million kilometers per hour, and circled the entire Sun in a matter of minutes.

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[ylrjr]

Wouldn't the tsunami have taken over two hours to circle the sun? My math skills are nowhere near the level of most that post here, but the sun's circumference is over 4 million km. If the tsunami travelled at one million km/hr, it would theoretically meet itself on the opposite side in a little over two hours. Am I wrong?

[Guest]

You're not wrong. But then, 120 minutes is still a matter of "minutes", albeit a lot of them.

Another issue to nitpick:
The Hydrogen-alpha line (which is the wavelength that I suspect was used to take the picture) is also emitted as part of the black body radiation that any sufficiently hot gas would produce. So it is not exclusive to Hydrogen, but it is produced in much greater quantities by that particular element.

[madtom1999]

Is this meant to be an animated gif?

[De58te]

When some people say a matter of minutes I usually don't think they intend to take over 4 hours. But it is just a matter of semantics. The Sun's circumference is roughly 4,370,000 km. So if the Moreton Wave's speed is 1 million kmph then it would take over 4 hours to circle the Sun. Semantically you can say that is just a matter of 240 minutes. At least.

[AVAO]

https://upload.wikimedia.org/wikipedia/ ... 200612.gif

I find it difficult to interpret the animation correctly. On the one hand, I see a linear flare-up along a "stress front" with an irregular slow shock wave, which is overtaken by a faster circular shock wave emanating from the center in about the middle of the animation.

more detailed scientific information can be found here:
https://iopscience.iop.org/article/10.1 ... /723/1/587

[Chris Peterson]

You're not wrong. But then, 120 minutes is still a matter of "minutes", albeit a lot of them.

Another issue to nitpick:
The Hydrogen-alpha line (which is the wavelength that I suspect was used to take the picture) is also emitted as part of the black body radiation that any sufficiently hot gas would produce. So it is not exclusive to Hydrogen, but it is produced in much greater quantities by that particular element.

If we're looking at fine points, it's not correct to refer to the "color" of the Ha output. It's a wavelength. Color is physiological, and the exact same color could be achieved by an infinite number of mixes of other wavelengths.

[smitty]

Is this meant to be an animated gif?

This is my question, too. I get a brief, gif-like animation when I first pull up the APOD website, but then there's no way to see it repeated. (No "play" icon).

[Chris Peterson]

Is this meant to be an animated gif?

This is my question, too. I get a brief, gif-like animation when I first pull up the APOD website, but then there's no way to see it repeated. (No "play" icon).

It is an animated GIF set to loop forever. However, such GIFs frequently fail in browsers, typically by running through only once. If you save the image to your computer and open it in your default image viewer you're likely to see it as intended.

[smitty]

Thank you!

[orin stepanek]

Sunspot on the sun! Source of tsunami?

kitty says; "Now that's a big tsunami"!

[Ann]

In spite of the impressive tsunami shock wave seen on the Sun in today's APOD, our dear old Sol really is very well-behaved and quiet as stars go:

Reuters wrote:

The sun appears to be far less active than similar stars in terms of brightness variations caused by sunspots and other phenomena - a “boring” personality, according to scientists, that may not be a bad thing for us Earthlings.

Researchers said on Thursday that an examination of 369 stars similar to the sun in surface temperatures, size and rotation period - it takes the sun about 24-1/2 days to rotate once on its axis - showed that they displayed on average five times more brightness variability than the sun.

(...)

"Temperature and rotation period are thought to be the major ingredients for the dynamo inside the star, which generates its magnetic field, and eventually the number and size of the spots causing the brightness to vary. Finding such stars with very similar parameters as our sun but being five times more variable was surprising," Reinhold said.

Elevated magnetic activity associated with sunspots can lead to solar flares, coronal mass ejections - large expulsions of plasma and magnetic field from the outermost part of the sun’s atmosphere - and other electromagnetic phenomena that can affect Earth, for example disrupting satellites and communications and endangering astronauts.

Solar monotony may be good news.

“A much more active sun might have also affected Earth on geological time scales - paleoclimatology. A ‘too active’ star would definitively change the conditions for life on the planet, so living with a quite boring star is not the worst option,” Reinhold said.

---

We've got a well-behaved schoolboy/schoolgirl for a Sun!

Ann

[johnnydeep]

In spite of the impressive tsunami shock wave seen on the Sun in today's APOD, our dear old Sol really is very well-behaved and quiet as stars go:

Reuters wrote:

The sun appears to be far less active than similar stars in terms of brightness variations caused by sunspots and other phenomena - a “boring” personality, according to scientists, that may not be a bad thing for us Earthlings.

Researchers said on Thursday that an examination of 369 stars similar to the sun in surface temperatures, size and rotation period - it takes the sun about 24-1/2 days to rotate once on its axis - showed that they displayed on average five times more brightness variability than the sun.

(...)

"Temperature and rotation period are thought to be the major ingredients for the dynamo inside the star, which generates its magnetic field, and eventually the number and size of the spots causing the brightness to vary. Finding such stars with very similar parameters as our sun but being five times more variable was surprising," Reinhold said.

Elevated magnetic activity associated with sunspots can lead to solar flares, coronal mass ejections - large expulsions of plasma and magnetic field from the outermost part of the sun’s atmosphere - and other electromagnetic phenomena that can affect Earth, for example disrupting satellites and communications and endangering astronauts.

Solar monotony may be good news.

“A much more active sun might have also affected Earth on geological time scales - paleoclimatology. A ‘too active’ star would definitively change the conditions for life on the planet, so living with a quite boring star is not the worst option,” Reinhold said.

---

We've got a well-behaved schoolboy/schoolgirl for a Sun!

Ann

Pretty surprising actually. Appears to be yet another way that the Sol/Earth/Moon system - plus Jupiter running cometary interference for us! - is ideally suited to "life as we know it". Of course, "life as we know it" evolved in exactly that system, so what else would we expect?!

[Chris Peterson]

We've got a well-behaved schoolboy/schoolgirl for a Sun!

Pretty surprising actually. Appears to be yet another way that the Sol/Earth/Moon system - plus Jupiter running cometary interference for us! - is ideally suited to "life as we know it". Of course, "life as we know it" evolved in exactly that system, so what else would we expect?!

Indeed. I wonder how many intelligent species floating in the atmospheres of gas giants, or swimming in liquid methane seas are saying exactly the same thing.

[johnnydeep]

We've got a well-behaved schoolboy/schoolgirl for a Sun!

Pretty surprising actually. Appears to be yet another way that the Sol/Earth/Moon system - plus Jupiter running cometary interference for us! - is ideally suited to "life as we know it". Of course, "life as we know it" evolved in exactly that system, so what else would we expect?!

Indeed. I wonder how many intelligent species floating in the atmospheres of gas giants, or swimming in liquid methane seas are saying exactly the same thing.

The "we are special" meme always puts me in mind of this poem:

Heaven
RUPERT BROOKE

FISH (fly-replete, in depth of June,
Dawdling away their wat’ry noon)
Ponder deep wisdom, dark or clear,
Each secret fishy hope or fear.
Fish say, they have their Stream and Pond;
But is there anything Beyond?
This life cannot be All, they swear,
For how unpleasant, if it were!
One may not doubt that, somehow, Good
Shall come of Water and of Mud;
And, sure, the reverent eye must see
A Purpose in Liquidity.
We darkly know, by Faith we cry,
The future is not Wholly Dry.
Mud unto mud! — Death eddies near —
Not here the appointed End, not here!
But somewhere, beyond Space and Time.
Is wetter water, slimier slime!
And there (they trust) there swimmeth One
Who swam ere rivers were begun,
Immense, of fishy form and mind,
Squamous, omnipotent, and kind;
And under that Almighty Fin,
The littlest fish may enter in.
Oh! never fly conceals a hook,
Fish say, in the Eternal Brook,
But more than mundane weeds are there,
And mud, celestially fair;
Fat caterpillars drift around,
And Paradisal grubs are found;
Unfading moths, immortal flies,
And the worm that never dies.
And in that Heaven of all their wish,
There shall be no more land, say fish.

[NCTom]

I sometimes become a bit impatient with the phrase "looking for evidence of life" when what is meant is "looking for life as we know it". Maybe we do have to look for what we understand, but it is still a little anthropomorphically limiting not to imply other forms of life may be waiting to be met. Thanks for those last two comments, Chris and Johnnydeep.

[Ann]

I sometimes become a bit impatient with the phrase "looking for evidence of life" when what is meant is "looking for life as we know it". Maybe we do have to look for what we understand, but it is still a little anthropomorphically limiting not to imply other forms of life may be waiting to be met. Thanks for those last two comments, Chris and Johnnydeep.

Certainly, Tom, but looking for life as we don't know it may be a lot harder than recognizing life forms whose basic makeup we are reasonably familiar with.

Consider life swimming in liquid methane seas. According to Google, the melting point of methane is 90.694 K and its boiling point is 111.6 K.

Yes, that's a surprising difference in the number of decimal points.

In order not to seize up and freeze to death under such conditions, life forms living in liquid methane lakes should have liquid methane themselves in their "veins". Do we understand the workings of such life forms well enough to see signs of their presence if we were to spot a planet where they exist?

Could we spot them in liquid lakes on Titan in our own solar system if they exist there?

Ann

[Fred the Cat]

If the moon formed during the Hadean eon

and life began to develop in the Cambrian, would carbon copies need a similar beginning?

The day the dinosaurs died had a lot to do with our rise to ask such questions. Could spherules have been ejected into space to travel elsewhere

[Chris Peterson]

I sometimes become a bit impatient with the phrase "looking for evidence of life" when what is meant is "looking for life as we know it". Maybe we do have to look for what we understand, but it is still a little anthropomorphically limiting not to imply other forms of life may be waiting to be met. Thanks for those last two comments, Chris and Johnnydeep.

Well, we're looking in places where life might reasonably be similar to life on Earth. And when you're designing experiments to look for it, the only rational thing to look for is life based on the same basic chemistry we use. That said, it's likely that even a very different kind of life would create signatures that we'd pick up with our instruments and demand explanation.