APOD: The Bubble and M52 (2013 Oct 08)

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APOD: The Bubble and M52 (2013 Oct 08)

Post by APOD Robot » Tue Oct 08, 2013 4:16 am

Image The Bubble and M52

Explanation: To the eye, this cosmic composition nicely balances the Bubble Nebula at the lower left with open star cluster M52 above it and to the right. The pair would be lopsided on other scales, though. Embedded in a complex of interstellar dust and gas and blown by the winds from a single, massive O-type star, the Bubble Nebula, also known as NGC 7635, is a mere 10 light-years wide. On the other hand, M52 is a rich open cluster of around a thousand stars. The cluster is about 25 light-years across. Seen toward the northern boundary of Cassiopeia, distance estimates for the Bubble Nebula and associated cloud complex are around 11,000 light-years, while star cluster M52 lies nearly 5,000 light-years away. The wide telescopic field of view spans about two degrees on the sky or four times the apparent size of the Full Moon.

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Beyond » Tue Oct 08, 2013 4:25 am

It's that cute widdle wed bubble again. :yes:

M52 has about 1000 stars :?:
Click to play embedded YouTube video.
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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Nitpicker » Tue Oct 08, 2013 5:10 am

Amazing photo of a spot rarely/never visible to we Southerners.

However, the numbers quoted in the caption do not appear to add up (to me). The nebula (NGC 7635) is said to be both (absolutely) smaller and further away than the cluster (M52), yet the cluster appears smaller than the nebula.

Are the "boundaries" of these objects discernible in this photo, or are they illusive?

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Nitpicker » Tue Oct 08, 2013 5:26 am

Unless the absolute size of the nebula only refers to the little circular bubble in amongst all the red cloud. Edit: yes, that's what the link in caption says, but is not the nebula considered to be more than just the bubble? Edit again: and would you really say that the small circular bubble balances the cluster to the eye?

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Markus Schwarz » Tue Oct 08, 2013 7:37 am

Nitpicker wrote:However, the numbers quoted in the caption do not appear to add up (to me). The nebula (NGC 7635) is said to be both (absolutely) smaller and further away than the cluster (M52), yet the cluster appears smaller than the nebula.
I had the same issue. However, the caption says the "Bubble Nebula and associated cloud complex are around 11,000 light-years" away. I guess the nebula is only a small part of the red cloud, as hinted by the link in the caption.

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The Hunt for Red October

Post by neufer » Tue Oct 08, 2013 11:00 am

http://en.wikipedia.org/wiki/Red_Cloud wrote: <<Red Cloud (Lakota: Maȟpíya Lúta), (1822 – December 10, 1909) was a chief of the Oglala Lakota (Sioux) from 1868 to 1909. One of the most capable Native American opponents the United States Army faced, he led a successful campaign in 1866–1868 known as Red Cloud's War over control of the Powder River Country in northeastern Wyoming and southern Montana. President John F. Kennedy once considered naming one of the 41 for Freedom ballistic missile submarines after Red Cloud, but apparently bowed to Pentagon concerns that the name could be misinterpreted as being pro-Communist.

Red Cloud was born close to the forks of the Platte River, near the modern-day city of North Platte, Nebraska. His mother, Walks As She Thinks, was an Oglala Lakota and his father, Lone Man, was a Brulé Lakota chief. Red Cloud was mentored as a boy by his maternal uncle, Old Chief Smoke (1774–1864). At a young age, Red Cloud fought against neighboring Pawnee & Crow, gaining much war experience.

In December 1866, Captain William J. Fetterman was sent from Fort Phil Kearny with 79 cavalry to chase away a small Indian war party that had attacked a wood party days before. He disobeyed orders to pursue a small decoy band of warriors, led by an Indian on an apparently injured horse. Fetterman and his troops followed the decoy (a.k.a., Crazy Horse) into a fatal ambush by more than 2,000 Sioux, Cheyenne, and Arapaho. A US peace commission later found that the American Indians had been provoked by white encroachment and recommended assigning definite territories to the Plains tribes. The Lakota, Northern Cheyenne, and Arapaho bands, and others settled for peace with the US under the Treaty of Fort Laramie. In return, the US agreed to abandon its forts and withdraw completely from Lakota territory.

However, in 1874, General George Custer led a reconnaissance mission into Sioux territory that reported gold in the Black Hills, an area held sacred by the local Indians. Formerly, the Army tried to keep miners out but did not succeed; the threat of violence grew. In May 1875, Sioux delegations headed by Red Cloud, Spotted Tail, and Lone Horn traveled to Washington, D.C. in an attempt to persuade President Grant to honor existing treaties and stem the flow of miners into their lands. The Indians met on various occasions with Grant, Secretary of the Interior Delano, and Commissioner of Indian Affairs Smith. He told them on May 27 that Congress was ready to resolve the matter by paying the tribes $25,000 for their land and resettling them into Indian Territory. The delegates refused to sign such a treaty, with Spotted Tail saying about the proposal: “When I was here before, the President gave me my country, and I put my stake down in a good place, and there I want to stay.... You speak of another country, but it is not my country; it does not concern me, and I want nothing to do with it. I was not born there.... If it is such a good country, you ought to send the white men now in our country there and let us alone.

Although Red Cloud was unsuccessful in finding a peaceful solution, he did not take part in the Lakota war of 1876-1877, which was led by Tȟašúŋke Witkó (Crazy Horse) and Tȟatȟáŋka Íyotake (Sitting Bull). However, Red Cloud became an important leader of the Lakota as they transitioned from the freedom of the plains to the confinement of the reservation system. His trip to Washington, D.C. had convinced him of the number and power of European Americans, and he believed the Oglala had to seek peace. Red Cloud is quoted as saying in his old age, "They made us many promises, more than I can remember. But they kept but one--They promised to take our land...and they took it.">>
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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by MargaritaMc » Tue Oct 08, 2013 6:50 pm

Nitpicker wrote:Unless the absolute size of the nebula only refers to the little circular bubble in amongst all the red cloud. Edit: yes, that's what the link in caption says, but is not the nebula considered to be more than just the bubble? Edit again: and would you really say that the small circular bubble balances the cluster to the eye?
I also find the numbers strange.

http://www.sidleach.com/m52_ngc7635.htm

The image at this link makes more sense of these figures.
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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Boomer12k » Tue Oct 08, 2013 11:25 pm

Really NICE!!!

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Nitpicker » Tue Oct 08, 2013 11:39 pm

After reading the caption several times, it occurs to me that perhaps the lopsidedness being alluded to, is the fact that within the nebula, there is a sparse region of space ~10ly in diameter, containing only one massive star, whilst in the cluster, a moderately larger region of space ~25ly across, contains ~1000 stars. Fairy nuff. Clear as mud!

It is still unclear to me whether the Bubble Nebula is considered to include the associated red cloud complex or not. To the eye, the nice balance achieved between the nebula and cluster is only because of the presence of the associated red cloud complex. So, as far as the caption is concerned, perhaps the red cloud is a red herring.

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Nitpicker » Wed Oct 09, 2013 12:23 am

It seems reasonable to me, that the Bubble Nebula is primarily a molecular cloud. The stellar winds from the massive O-type star (within the molecular cloud), create the circular ionised bubble and the light from the star illuminates the remainder of the molecular cloud outside the bubble.

As such, could the Bubble Nebula be thought of as a combination of emission and reflection nebula, covering the circular bubble and the red cloud respectively? Is this reasonable?

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Nitpicker » Wed Oct 09, 2013 2:52 am

Nitpicker wrote:could the Bubble Nebula be thought of as a combination of emission and reflection nebula, covering the circular bubble and the red cloud respectively? Is this reasonable?
According to some, the Bubble Nebula (NGC7635) is surrounded by a partially ionised HII region named Sharpless 162 (S162). Some others state that NGC7635 and S162 are one and the same. Either way, it appears I'm wrong about any of it being a reflection nebula. I dunno anymore, tis all dim light below the horizon to me.

Going dark for a few days ...

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by Don Bullock » Sat Oct 19, 2013 4:52 pm

It occurs to me that this picture almost looks like a city viewed from a high altitude with street lights along the roads and a large fire burning at one location. There is a regularity about the "roads" and I wonder how they were formed.

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Re: APOD: The Bubble and M52 (2013 Oct 08)

Post by geckzilla » Sat Oct 19, 2013 5:05 pm

Don Bullock wrote:It occurs to me that this picture almost looks like a city viewed from a high altitude with street lights along the roads and a large fire burning at one location. There is a regularity about the "roads" and I wonder how they were formed.
Not sure what you mean by roads but if you are seeing patterns in the stars that is a natural way our brains process information by picking out patterns. In order to keep from fooling oneself it is important to realize when this is happening and learn how to overcome it. Any given asterism (a pattern formed by stars, such as a straight line) is just a random alignment and stars which appear close to one another are actually very far apart and not forming any kind of line at all when depth or what you might call a z-axis is considered.
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