Starship Asterisk*

The Meteor and the Galaxy

Explanation: It came from outer space. It -- in this case a sand-sized bit of a comet nucleus -- was likely ejected many years ago from Sun-orbiting Comet Swift-Tuttle, but then continued to orbit the Sun alone. When the Earth crossed through this orbit, the piece of comet debris impacted the atmosphere of our fair planet and was seen as a meteor. This meteor deteriorated, causing gases to be emitted that glowed in colors emitted by its component elements. The featured image was taken last week from Castilla La Mancha, Spain, during the peak night of the Perseids meteor shower. The picturesque meteor streak happened to appear in the only one of 50 frames that also included the Andromeda galaxy. Stars dot the frame, each much further away than the meteor. Compared to the stars, the Andromeda galaxy (M31) is, again, much further away.

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I would think that the meteor was at least the size of a small pebble. Most meteors don't create visible trails that drift - but the larger ones do.

That's a mean meteor to be sure!! I'd love to know all the elements that caused all the colors that we can see in the meteor. It goes without saying that I'm most interested in what caused to bluish cyan color!

The juxtaposition of the meteor and the galaxy is striking and fantastic indeed! Bravo! (And now I've used up all my smilies. Oh well.)

Me being me however, you can't show me a picture like this without me beginning to wonder about the "relative colors" of the things in it. Obvious first reaction: Andromeda sure looks red here!

Second thought: I know there is a reasonably bright and very blue star in the vicinity of Andromeda. Where is it? I can't see it... Oh! There it is! And it looks all white! It's Nu Andromedae.

For comparison, let's look at a closeup of the the part of the APOD showing Andromeda and surroundings, including Nu Andromedae, and a picture by Davide De Martin showing Andromeda and Nu Andromedae:



There are in fact a number of somewhat weirdly colored stars in the APOD, where, as I said, blue Nu Andromedae looks non-blue, but some non-blue stars look blue. And many very faint stars look very blue, although they are not.

Oh well! You know that I am the one who would pay attention to these things!

Ann

Fascinated by all APODs, thank you. Have little to add to discussions but enjoyed the image that appeared when I clicked on the word "only" in the text today.

Text says meteor trail glows with colors of its own ablated elements, but what of atmospheric elements through which it is plowing? Won't we see colors from heated/ionized nitrogen and oxygen as well?

Uncle Jeff wrote: ↑Wed Aug 23, 2023 3:57 pm Text says meteor trail glows with colors of its own ablated elements, but what of atmospheric elements through which it is plowing? Won't we see colors from heated/ionized nitrogen and oxygen as well?

Yes. RGB camera images (and our eyes) are not reliable for assessing what meteors are made of. There is a complex mix of continuum light and emission lines from both meteor elements and atmospheric gases.

What causes those brushstroke-looking wisps of varying colors that trail off unilaterally on one side or the other of the main trail?

johnnydeep wrote: ↑Wed Aug 23, 2023 5:23 pm What causes those brushstroke-looking wisps of varying colors that trail off unilaterally on one side or the other of the main trail?

Drifting dust, drifting ionized gas.

Ahh; Andromeda; always beautiful to look at! It will marry with
the Milkyway some day!

Chris Peterson wrote: ↑Wed Aug 23, 2023 5:38 pm

johnnydeep wrote: ↑Wed Aug 23, 2023 5:23 pm What causes those brushstroke-looking wisps of varying colors that trail off unilaterally on one side or the other of the main trail?

Drifting dust, drifting ionized gas.

So, that's due to atmospheric motion and wind? I would expect that to appear on only one side, not both as is shown here. Is there that much turbulence in the air over this distance? How long is this trail anyway?

johnnydeep wrote: ↑Wed Aug 23, 2023 8:12 pm

Chris Peterson wrote: ↑Wed Aug 23, 2023 5:38 pm

johnnydeep wrote: ↑Wed Aug 23, 2023 5:23 pm What causes those brushstroke-looking wisps of varying colors that trail off unilaterally on one side or the other of the main trail?

Drifting dust, drifting ionized gas.

So, that's due to atmospheric motion and wind? I would expect that to appear on only one side, not both as is shown here. Is there that much turbulence in the air over this distance? How long is this trail anyway?

The trail is probably tens of kilometers long. Wind direction changes significantly with height, and in some cases here the wind may be nearly in our line of site, so could result in material close to the trail but on either side.

Chris Peterson wrote: ↑Wed Aug 23, 2023 8:26 pm

johnnydeep wrote: ↑Wed Aug 23, 2023 8:12 pm

Chris Peterson wrote: ↑Wed Aug 23, 2023 5:38 pm

Drifting dust, drifting ionized gas.

So, that's due to atmospheric motion and wind? I would expect that to appear on only one side, not both as is shown here. Is there that much turbulence in the air over this distance? How long is this trail anyway?

The trail is probably tens of kilometers long. Wind direction changes significantly with height, and in some cases here the wind may be nearly in our line of site, so could result in material close to the trail but on either side.

Ok, that makes perfect sense then.

That meteor smacked into the mesosphere at 37 miles per second. Size and configuration not known, but created a lot of ions. Evidenced by a red sprite characteristic of mesosphere’s fluorescence above stratospheric arcing lightning. The straight “feathering” reaching out from the meteor track to the sprite appears to be arcing discharge of ions to the lower larger area of the sprite, where the excess ions dissipate.

Roy wrote: ↑Wed Aug 23, 2023 9:33 pm That meteor smacked into the mesosphere at 37 miles per second. Size and configuration not known, but created a lot of ions. Evidenced by a red sprite characteristic of mesosphere’s fluorescence above stratospheric arcing lightning. The straight “feathering” reaching out from the meteor track to the sprite appears to be arcing discharge of ions to the lower larger area of the sprite, where the excess ions dissipate.

The upper orange structure is almost certainly the very typical Na and FeO driven airglow commonly observed in persistent trains. The lower "red" spike may be the same. I note that it appears almost exactly the same color as Andromeda, which is most certainly not very close to its "true" color here, so I'd be cautious interpreting it as a sprite.

Persistent train formation is associated with passage through a fairly narrow height range, perhaps 80-90 km, the very upper mesosphere bordering on the thermosphere. The trail itself is visible over a much wider range of heights.

Chris Peterson wrote: ↑Wed Aug 23, 2023 9:58 pm

Roy wrote: ↑Wed Aug 23, 2023 9:33 pm That meteor smacked into the mesosphere at 37 miles per second. Size and configuration not known, but created a lot of ions. Evidenced by a red sprite characteristic of mesosphere’s fluorescence above stratospheric arcing lightning. The straight “feathering” reaching out from the meteor track to the sprite appears to be arcing discharge of ions to the lower larger area of the sprite, where the excess ions dissipate.

The upper orange structure is almost certainly the very typical Na and FeO driven airglow commonly observed in persistent trains. The lower "red" spike may be the same. I note that it appears almost exactly the same color as Andromeda, which is most certainly not very close to its "true" color here, so I'd be cautious interpreting it as a sprite.

Persistent train formation is associated with passage through a fairly narrow height range, perhaps 80-90 km, the very upper mesosphere bordering on the thermosphere. The trail itself is visible over a much wider range of heights.

To me the reddish outflows from the trail look like they may have been caused by some minor explosions, the kind of explosions that wouldn't destroy the tiny rocky body that is responsible for the meteor in the first place. Am I completely wrong about this?

And I'm glad you (basically) agree with me about the color of Andromeda in the APOD, although I don't think that Andromeda appears to be the same color as the reddish outflows from the meteor trail.

Ann

Ann wrote: ↑Thu Aug 24, 2023 3:10 am

Chris Peterson wrote: ↑Wed Aug 23, 2023 9:58 pm

Roy wrote: ↑Wed Aug 23, 2023 9:33 pm That meteor smacked into the mesosphere at 37 miles per second. Size and configuration not known, but created a lot of ions. Evidenced by a red sprite characteristic of mesosphere’s fluorescence above stratospheric arcing lightning. The straight “feathering” reaching out from the meteor track to the sprite appears to be arcing discharge of ions to the lower larger area of the sprite, where the excess ions dissipate.

The upper orange structure is almost certainly the very typical Na and FeO driven airglow commonly observed in persistent trains. The lower "red" spike may be the same. I note that it appears almost exactly the same color as Andromeda, which is most certainly not very close to its "true" color here, so I'd be cautious interpreting it as a sprite.

Persistent train formation is associated with passage through a fairly narrow height range, perhaps 80-90 km, the very upper mesosphere bordering on the thermosphere. The trail itself is visible over a much wider range of heights.

To me the reddish outflows from the trail look like they may have been caused by some minor explosions, the kind of explosions that wouldn't destroy the tiny rocky body that is responsible for the meteor in the first place. Am I completely wrong about this?

And I'm glad you (basically) agree with me about the color of Andromeda in the APOD, although I don't think that Andromeda appears to be the same color as the reddish outflows from the meteor trail.

Ann

Yes, it is quite common for larger bodies (centimeters or more) to fragment along their path, releasing bursts of material.

It's that lower, spiky one that looks to me very close to the color of Andromeda.

Chris Peterson wrote: ↑Thu Aug 24, 2023 4:22 am

Ann wrote: ↑Thu Aug 24, 2023 3:10 am

Chris Peterson wrote: ↑Wed Aug 23, 2023 9:58 pm

The upper orange structure is almost certainly the very typical Na and FeO driven airglow commonly observed in persistent trains. The lower "red" spike may be the same. I note that it appears almost exactly the same color as Andromeda, which is most certainly not very close to its "true" color here, so I'd be cautious interpreting it as a sprite.

Persistent train formation is associated with passage through a fairly narrow height range, perhaps 80-90 km, the very upper mesosphere bordering on the thermosphere. The trail itself is visible over a much wider range of heights.

To me the reddish outflows from the trail look like they may have been caused by some minor explosions, the kind of explosions that wouldn't destroy the tiny rocky body that is responsible for the meteor in the first place. Am I completely wrong about this?

And I'm glad you (basically) agree with me about the color of Andromeda in the APOD, although I don't think that Andromeda appears to be the same color as the reddish outflows from the meteor trail.

Ann

Yes, it is quite common for larger bodies (centimeters or more) to fragment along their path, releasing bursts of material.

It's that lower, spiky one that looks to me very close to the color of Andromeda.

Indeed, the color of Andromeda and the color of the lower spiky outflow appear to be virtually identical, about this color: ███. But if so, then the color of the two reddish outflows from the meteor trail can't be caused by the same elements, because the upper, larger outflow is about this color: ███.

Ann

Ann wrote: ↑Thu Aug 24, 2023 5:02 am

Chris Peterson wrote: ↑Thu Aug 24, 2023 4:22 am

Ann wrote: ↑Thu Aug 24, 2023 3:10 am

To me the reddish outflows from the trail look like they may have been caused by some minor explosions, the kind of explosions that wouldn't destroy the tiny rocky body that is responsible for the meteor in the first place. Am I completely wrong about this?

And I'm glad you (basically) agree with me about the color of Andromeda in the APOD, although I don't think that Andromeda appears to be the same color as the reddish outflows from the meteor trail.

Ann

Yes, it is quite common for larger bodies (centimeters or more) to fragment along their path, releasing bursts of material.

It's that lower, spiky one that looks to me very close to the color of Andromeda.

Indeed, the color of Andromeda and the color of the lower spiky outflow appear to be virtually identical, about this color: ███. But if so, then the color of the two reddish outflows from the meteor trail can't be caused by the same elements, because the upper, larger outflow is about this color: ███.

Ann

FWIW, here are the three colors that my new Color Picker PowerToy tool reveals, though the particular colors are highly dependent on where in the three areas you pick! And yes, I think the lower smaller feathering is close to the color of Andromeda:

Ann wrote: ↑Thu Aug 24, 2023 5:02 am

Chris Peterson wrote: ↑Thu Aug 24, 2023 4:22 am

Ann wrote: ↑Thu Aug 24, 2023 3:10 am

To me the reddish outflows from the trail look like they may have been caused by some minor explosions, the kind of explosions that wouldn't destroy the tiny rocky body that is responsible for the meteor in the first place. Am I completely wrong about this?

And I'm glad you (basically) agree with me about the color of Andromeda in the APOD, although I don't think that Andromeda appears to be the same color as the reddish outflows from the meteor trail.

Ann

Yes, it is quite common for larger bodies (centimeters or more) to fragment along their path, releasing bursts of material.

It's that lower, spiky one that looks to me very close to the color of Andromeda.

Indeed, the color of Andromeda and the color of the lower spiky outflow appear to be virtually identical, about this color: ███. But if so, then the color of the two reddish outflows from the meteor trail can't be caused by the same elements, because the upper, larger outflow is about this color: ███.

Ann

I am quite certain the upper trail is airglow. Can't say for sure about the lower one, but again, don't overanalyze the color. There are dozens of components that are all getting mixed together into just three display channels. That lower spike could be created by the same thing making up the upper zone, simply mixed with something else or illuminated differently or even just a different intensity.