APOD: The Deep Sky Toward Andromeda (2021 Sep 08)

Comments and questions about the APOD on the main view screen.
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Ann
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Re: APOD: The Deep Sky Toward Andromeda (2021 Sep 08)

Post by Ann » Sat Sep 11, 2021 4:23 am

VictorBorun wrote:
Sat Sep 11, 2021 3:37 am
johnnydeep wrote:
Fri Sep 10, 2021 1:43 pm
VictorBorun wrote:
Fri Sep 10, 2021 3:28 am
You just went and deleted the largest mushroom stem in question!
Making it just an interface between two bubbles, a wall or a membrane visually thickening where it's edge-on for us.
A bubble can well have radius of 10 ly. No magnetic tube required
Well, how do we really distinguish between the two? Sometimes I think we are too prone to see things that aren't really there.
I think
1) a jet in a magnetic tube has smooth cylinder walls while
2) a wall or a filament between 2 or 3 touching bubbles has a hazy surface of trailing matter all around and
3) a cometary trunk is smoothe at its head part and has a source of stellar wind in its vicinity blowing onto the head

Look at an edge-on disk galaxy. The dusty curls at the both surfaces of the disk look like parts of bubbles' shells visible where a bubble crushes into the dense bubble foam of the disk. Those dusty lanes are hazy all over.
And look at a planetary nebula. The walls are glossy-smoothe:

The reason why there are "bubbles" emanating from the central dust lane of spiral galaxies is that there have been numerous powerful supernova explosions from massive stars in the dust lane. (And there have been powerful supernova events of type Ia from not so massive stars, too.)

Not all planetary nebulas are glassy-smooth. I'd say that few are. But the difference between the "bubbles" (which are called chimneys) in the central dust lane of spiral galaxies and and the shape of the outflows of planetary nebulas is that the chimneys in spiral galaxies have been caused by so very many stellar explosions, whereas the planetary nebula has been cause by just one star (single or binary) that "shrugged off" its outer atmosphere and started blowing a very harsh stellar wind.


There are two huge gamma ray bubbles emanating from the center of the Milky Way, which are probably the remnants of some sort of incredibly powerful outburst from our galaxy's central black hole.

So I'd say there is not a great shortage of bubbles in the Universe. Rings, however, seems like another matter to me.

But surely the Earth moves along a ring-shaped orbit, right? Well, not exactly.

Click to play embedded YouTube video.

Check out this video, almost 22 minutes long (sorry), on how the Earth moves.

Ann
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VictorBorun
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Re: APOD: The Deep Sky Toward Andromeda (2021 Sep 08)

Post by VictorBorun » Sat Sep 11, 2021 10:22 pm

Ann wrote:
Sat Sep 11, 2021 4:23 am
So I'd say there is not a great shortage of bubbles in the Universe. Rings, however, seems like another matter to me.
Ann
A one star's bubble is entitled to have a ring, isn't it? I mean, if the nucleosynthesis in the star's core fades and the star collapses and spins up, some of the mass is thrown away to keep the total spin constant. Naturally the equatorial part of the surface would be the first to get fired.
The bubble and the ring should be easily recognized as:
1) both have the same stellar remnant as their center
2) the ring is denser and smaller that the bubble
3) the ring's outer edge is hazy with cometary tails
4) the inner surface of the bubble shell is hazy because of slow trailing fractions
5) the outer surface of the bubble shell is dense like a bulldozer pushing out the interstellar media

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neufer
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I've heard that's where it leads...

Post by neufer » Sat Sep 11, 2021 10:57 pm

VictorBorun wrote:
Sat Sep 11, 2021 10:22 pm
Ann wrote:
Sat Sep 11, 2021 4:23 am

So I'd say there is not a great shortage of bubbles in the Universe.
Rings, however, seems like another matter to me.
A one star's bubble is entitled to have a ring, isn't it? I mean, if the nucleosynthesis in the star's core fades and the star collapses and spins up, some of the mass is thrown away to keep the total spin constant. Naturally the equatorial part of the surface would be the first to get fired.

The bubble and the ring should be easily recognized as:

1) both have the same stellar remnant as their center
2) the ring is denser and smaller that the bubble
3) the ring's outer edge is hazy with cometary tails
4) the inner surface of the bubble shell is hazy because of slow trailing fractions
5) the outer surface of the bubble shell is dense like a bulldozer pushing out the interstellar media
Click to play embedded YouTube video.
Art Neuendorffer

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Re: APOD: The Deep Sky Toward Andromeda (2021 Sep 08)

Post by Fred the Cat » Sun Sep 12, 2021 2:41 am

neufer wrote:
Sat Sep 11, 2021 10:57 pm
VictorBorun wrote:
Sat Sep 11, 2021 10:22 pm
Ann wrote:
Sat Sep 11, 2021 4:23 am

So I'd say there is not a great shortage of bubbles in the Universe.
Rings, however, seems like another matter to me.
A one star's bubble is entitled to have a ring, isn't it? I mean, if the nucleosynthesis in the star's core fades and the star collapses and spins up, some of the mass is thrown away to keep the total spin constant. Naturally the equatorial part of the surface would be the first to get fired.

The bubble and the ring should be easily recognized as:

1) both have the same stellar remnant as their center
2) the ring is denser and smaller that the bubble
3) the ring's outer edge is hazy with cometary tails
4) the inner surface of the bubble shell is hazy because of slow trailing fractions
5) the outer surface of the bubble shell is dense like a bulldozer pushing out the interstellar media
Click to play embedded YouTube video.
If I were a “two-dimensional” living on the edge of an expanding, twisting bubble, and could see other two-dimensional bubbles above, below, and even. What would I see :?:

I don’t know but my spinning brain might gravitate towards looking at things, bigger and smaller, that appear they’re falling into vortices or should.

Pass the ripple! :wink:
Freddy's Felicity "Only ascertain as a cat box survivor"

eshy76
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Re: APOD: The Deep Sky Toward Andromeda (2021 Sep 08)

Post by eshy76 » Thu Sep 16, 2021 4:40 pm

I love this image as whenever I target Andromeda, the last thing I think about is what lies behind it!