APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4407
Joined: Fri Dec 04, 2009 3:27 am

APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by APOD Robot » Tue Oct 11, 2016 4:07 am

Image The Cygnus Wall of Star Formation

Explanation: Sometimes, stars form in walls -- bright walls of interstellar gas. In this vivid skyscape, stars are forming in the W-shaped ridge of emission known as the Cygnus Wall. Part of a larger emission nebula with a distinctive outline popularly called The North America Nebula, the cosmic ridge spans about 20 light-years. Constructed using narrowband data to highlight the telltale reddish glow from ionized hydrogen atoms recombining with electrons, the image mosaic follows an ionization front with fine details of dark, dusty forms in silhouette. Sculpted by energetic radiation from the region's young, hot, massive stars, the dark shapes inhabiting the view are clouds of cool gas and dust with stars likely forming within. The North America Nebula itself, NGC 7000, is about 1,500 light-years away.

<< Previous APOD This Day in APOD Next APOD >>
[/b]

User avatar
Ann
4725 Å
Posts: 11520
Joined: Sat May 29, 2010 5:33 am

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by Ann » Tue Oct 11, 2016 5:54 am

Congratulations, Sara! I don't remember the last time a woman's image was made the Astronomy Picture of the Day.

Yours is very well-deserved. All the dusty features in and near the Cygnus Wall are very intriguing.

Ann
Color Commentator

starsurfer
Stellar Cartographer
Posts: 4491
Joined: Thu Mar 15, 2012 7:25 pm

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by starsurfer » Tue Oct 11, 2016 10:57 am

Ann wrote:Congratulations, Sara! I don't remember the last time a woman's image was made the Astronomy Picture of the Day.

Yours is very well-deserved. All the dusty features in and near the Cygnus Wall are very intriguing.

Ann
I concur! Female astrophotographers are very rare.

Muppet

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by Muppet » Tue Oct 11, 2016 4:15 pm

I think I see a fierce battle between hand puppets in the lower left corner.

User avatar
MarkBour
Subtle Signal
Posts: 1180
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by MarkBour » Tue Oct 11, 2016 6:02 pm

How opaque are the clouds? I would guess that they are more or less completely opaque. When I see a dark region with stars in it, my mind wants to assume the stars are shining through a mostly-clear darkness. For this picture, though, I'm guessing that all of the stars one sees in the otherwise dark cloudy regions are in front of the clouds of dust. Of course, someone, at some point, would need to establish that, but I assume that's been long since done. The black region at the upper left of the image is distinct from the brown region at the lower right, so the answers may be different for the two regions, maybe not. Is this correct for this image -- all of the stars in the dark regions are between us and an opaque cloud?
Mark Goldfain

ta152h0
Schooled
Posts: 1393
Joined: Mon Aug 29, 2005 12:46 am
Location: Auburn, Washington, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by ta152h0 » Tue Oct 11, 2016 7:19 pm

is this wall really of very tenuous density ? If you were able to maintain your human form and fly thru there, you would feel nothing, maybe.
Wolf Kotenberg

ta152h0
Schooled
Posts: 1393
Joined: Mon Aug 29, 2005 12:46 am
Location: Auburn, Washington, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by ta152h0 » Tue Oct 11, 2016 7:22 pm

never seen a woman's image on APOD ? Remember the Marylin Monroe nebula ?
Wolf Kotenberg

User avatar
Fred the Cat
Theoretic Apothekitty
Posts: 704
Joined: Mon Feb 22, 2016 4:09 pm
AKA: Ron
Location: Eagle, Idaho

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by Fred the Cat » Tue Oct 11, 2016 8:53 pm

I always wonder, "What would that nebula look like if you could see it in 3D?" 8-)
Freddy's Felicity "Only ascertain as a cat box survivor"

User avatar
MarkBour
Subtle Signal
Posts: 1180
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by MarkBour » Tue Oct 11, 2016 11:20 pm

Fred the Cat wrote:I always wonder, "What would that nebula look like if you could see it in 3D?" 8-)
That is fantastic. Actually, if they have all that data, they could make it interactive like the recent APOD image of C67P. I'd like that even better.
Mark Goldfain

User avatar
Chris Peterson
Abominable Snowman
Posts: 16139
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by Chris Peterson » Wed Oct 12, 2016 12:54 pm

MarkBour wrote:
Fred the Cat wrote:I always wonder, "What would that nebula look like if you could see it in 3D?" 8-)
That is fantastic. Actually, if they have all that data, they could make it interactive like the recent APOD image of C67P. I'd like that even better.
Don't overlook that there is little actual data here. The 3D reconstruction is largely speculative, and doesn't represent the actual 3D structure. Best to think of it as representative, to give a subjective sense of the 3D structure of such nebulas, not an objective representation of this particular nebula.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Chris Peterson
Abominable Snowman
Posts: 16139
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by Chris Peterson » Wed Oct 12, 2016 12:57 pm

MarkBour wrote:How opaque are the clouds? I would guess that they are more or less completely opaque.
You need to define what you mean by "opaque" when asking that kind of question. The densest parts of the clouds are still a hard vacuum. Much more tenuous than Earth's atmosphere, for instance. And our atmosphere is more opaque by orders of magnitude than this nebula.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18354
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by neufer » Wed Oct 12, 2016 3:30 pm

Chris Peterson wrote:
MarkBour wrote:
How opaque are the clouds? I would guess that they are more or less completely opaque.
You need to define what you mean by "opaque" when asking that kind of question. The densest parts of the clouds are still a hard vacuum. Much more tenuous than Earth's atmosphere, for instance. And our atmosphere is more opaque by orders of magnitude than this nebula.
https://en.wikipedia.org/wiki/Dark_nebula wrote: <<A dark nebula or absorption nebula is a type of interstellar cloud that is so dense it obscures the light from objects behind it, such as background stars and emission or reflection nebulae. The extinction of the light is caused by interstellar dust grains located in the coldest, densest parts of larger molecular clouds. Clusters and large complexes of dark nebulae are associated with Giant Molecular Clouds. In the inner outer molecular regions of dark nebulae, important events take place, such as the formation of stars and masers.

Dark clouds appear so because of sub-micrometre-sized dust particles, coated with frozen carbon monoxide and nitrogen, which effectively block the passage of light at visible wavelengths. Also present are molecular hydrogen, atomic helium, C18O (CO with oxygen as the 18O isotope), CS, NH3 (ammonia), H2CO (formaldehyde), c-C3H2 (cyclopropenylidene) and a molecular ion N2H+ (diazenylium), all of which are relatively transparent. These clouds are the spawning grounds of stars and planets, and understanding their development is essential to understanding star formation.

The form of such dark clouds is very irregular: they have no clearly defined outer boundaries and sometimes take on convoluted serpentine shapes. The largest dark nebulae are visible to the naked eye, appearing as dark patches against the brighter background of the Milky Way like the Coalsack Nebula and the Great rift. These naked-eye objects are sometimes known as dark cloud constellations and take on a variety of names.>>
Art Neuendorffer

dlw
Ensign
Posts: 88
Joined: Fri Jul 22, 2005 4:43 pm
Location: California

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by dlw » Wed Oct 12, 2016 5:47 pm

Beautiful! It bring to mind a very well known image of another form of "creation".
Creation.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
MarkBour
Subtle Signal
Posts: 1180
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: The Cygnus Wall of Star Formation (2016 Oct 11)

Post by MarkBour » Thu Oct 13, 2016 12:52 am

Chris Peterson wrote:
MarkBour wrote:How opaque are the clouds? I would guess that they are more or less completely opaque.
You need to define what you mean by "opaque" when asking that kind of question. The densest parts of the clouds are still a hard vacuum. Much more tenuous than Earth's atmosphere, for instance. And our atmosphere is more opaque by orders of magnitude than this nebula.
I see the vagueness possible in this question, but I'm using opaque in the basic sense "not able to be seen through" ... and I mean the cloud as a whole, not some portion of it. I tried to clarify it when I said: "I'm guessing that all of the stars one sees in the otherwise dark cloudy regions are in front of the clouds of dust."

I'm supposing that clever astronomers have found some way to decide the distance and rough extent of the clouds, and I'm betting they can do an even better job of telling the distance to many of the stars in the image. If we can see plenty of stars that are beyond the cloud, then I would not call it opaque in the sense I am asking. If we are not seeing any starlight that is coming to us through the cloud, then there is some evidence that it is sufficiently opaque to hide stars from us.
Mark Goldfain