APOD: M57: The Ring Nebula (2013 Jun 05)

[APOD Robot]

M57: The Ring Nebula

Explanation: Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. Its classic appearance is understood to be due to our own perspective, though. The recent mapping of the expanding nebula's 3-D structure, based in part on this clear Hubble image, indicates that the nebula is a relatively dense, donut-like ring wrapped around the middle of a football-shaped cloud of glowing gas. The view from planet Earth looks down the long axis of the football, face-on to the ring. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from the dying, once sun-like star, now a tiny pinprick of light seen at the nebula's center. Intense ultraviolet light from the hot central star ionizes atoms in the gas. In the picture, the blue color in the center is ionized helium, the cyan color of the inner ring is the glow of hydrogen and oxygen, and the reddish color of the outer ring is from nitrogen and sulfur. The Ring Nebula is about one light-year across and 2,000 light-years away.

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[/b]

[bystander]

http://asterisk.apod.com/viewtopic.php?t=31431

[PhilT]

We should all be truly humbled by this picture. We sit here on Earth worrying about how much energy our little planet is accumulating yet in this picture the outer rings are at approximately 5x the distance from our Sun to Pluto from their own central star. Even at that distance the light energy is still enough to ionise atoms. Amazing.

Earth is equally amazing, we should all count ourselves very lucky to be alive - and DO something to help our little planet cool down.

[Boomer12k]

WOW!
What an awesome spectacle. It looks like a large burning doughnut, with flames coming off of it. So sharp and detailed. Below is my best image of M57. A far cry, but I only have a ground based, 10 incher... I enhanced the photo on my tablet. Not as sharp as my eyes aren't so good for focusing. But it is one of my favorite objects, and my sister like to see it when she comes to visit.

Hubble never disappoints, I wish they were going to keep it going, or bring it back, or something. I think it can still contribute allot.

It is said by most sources to be 2300 ly distant...but one interesting note....it is Approaching us...at 21 km/s...so, in the far distant future, we should be getting a better look. And maybe those remnant gases and elements will be reused in another star...

:---[===] *

[JohnD]

Ahem! "Football"!
An American football, or a rugby football, but not a football football, which is sperical.
Apod is such an internationally used site, that we should use accurate analogies.


But may I ask? How, why, the stratification of elements in the nebula, that causes the half-sucked bullseye effect?

John the Pedant.

[Lasse H]

Thank you JohnD! This was my first reaction as a resident of a country outside the USA: "football-shaped"??? --- in most of the world, a football does not have any long axis (nor a short one, for that matter). Is parochial the word I am looking for?

[MargaritaMc]

Ahem! "Football"!
An American football, or a rugby football, but not a football football, which is sperical.
Apod is such an internationally used site, that we should use accurate analogies.

John the Pedant.

Hi, John the Pedant! We must be related - I'm Margarita the Pedant! I raised the issue of differing definitions of football-shape on THIS thread.

Here is some more research about the various shapes that can be called 'football'.

Wikipedia

Various leagues and games use different balls, though they all have one of the following basic shapes:

- a sphere: used in Association football and Gaelic football
- a prolate spheroid
--- either with rounded ends: used in the rugby codes and Australian football
--- or with more pointed ends: used in American football and Canadian football.

The precise shape and construction of footballs is typically specified as part of the rules and regulations.

The oldest football still in existence, which is thought to have been made circa 1540, was discovered in the roof of Stirling Castle, Scotland, in 1981. The ball is made of leather (possibly from a deer) and a pig's bladder. It has a diameter of between 14–16 cm (5.5–6.3 in), weighs 125 g (4.4 oz) and is currently on display at the Smith Art Gallery and Museum in Stirling.

The BBC have a photograph of this football
- and, as it can't be hotlinked, I've uploaded a copy here:

Oldest_football_1540.jpg

Margarita - also The Pedant

[starsurfer]

Ah the difference the lack of an atmosphere getting in the way makes with resolution! I'm surprised they used the closer view, I expected to see the one that shows the amazing outer halo, this can be viewed here: http://hubblesite.org/newscenter/archiv ... large_web/

[Beyond]

Ah the difference the lack of an atmosphere getting in the way makes with resolution! I'm surprised they used the closer view, I expected to see the one that shows the amazing outer halo, this can be viewed here: http://hubblesite.org/newscenter/archiv ... large_web/

WOW!! That's a good picture! It looks like you're looking right through it to the other side.

[Galaxian]

We should all be truly humbled by this picture. We sit here on Earth worrying about how much energy our little planet is accumulating yet in this picture the outer rings are at approximately 5x the distance from our Sun to Pluto from their own central star. Even at that distance the light energy is still enough to ionise atoms. Amazing.

Earth is equally amazing, we should all count ourselves very lucky to be alive - and DO something to help our little planet cool down.

Earth is amazing, also beautiful. And ever so fragile. I do my bit to help her, I run my computers 24/7, I keep the heating on until the outside temperature reaches 36C then start the air-blower thingy, I leave gadgets on standby and charging and I eat lots of meat.
My carbon footprint is more like a "Footfall" As it should be. We need *more* global warming, not less. Some years back, *dragons* filled our skies. Lizards larger than houses could fly. Earth today is too cold, the air too thin to support them. We need more global warming so we can bring back the dragons. Also so I never, ever, ever have to see snow again.
We need more and better tech for many other reasons, too.
This is a great, big, glorious universe and we should be out there playing in it, making it *ours*.
Greenpeace should be thinking about this: No human living exclusively on Mars can harm the cute bunnies or baby seals. [1]The best way to keep Earth green and fertile and lovely is to support NASA/JPL/ESA and all the other guys trying to help us get offworld. Protect the Spotted Owl pump money into NASA and ESA. Vote green, vote environment-friendly, support only candidates who fully endorse manned space exploration at *any* cost.
Remember: all the nasty plutonium in Voyager will never harm the cute bunnies.
Okay, so I'm selfish. I just want them to build Starships so I can captain one. I want my children to *fly* among the stars.

[1] apart from the ones that are also on Mars, which would be to the *advantage* of the bunnies. More territory, more worlds more bunnies means more furry cuteness and a better chance at eternity.

[neufer]

We should all be truly humbled by this picture. We sit here on Earth worrying about how much energy our little planet is accumulating yet in this picture the outer rings are at approximately 5x the distance from our Sun to Pluto from their own central star. Even at that distance the light energy is still enough to ionise atoms. Amazing.

The outer rings are at approximately 2,000x the distance from our Sun to Pluto from their own central star.

They have been moving faster than Voyager 1 for the last 16 centuries.

[Galaxian]

WOW!
What an awesome spectacle. It looks like a large burning doughnut, with flames coming off of it. So sharp and detailed. Below is my best image of M57. A far cry, but I only have a ground based, 10 incher... I enhanced the photo on my tablet. Not as sharp as my eyes aren't so good for focusing. But it is one of my favorite objects, and my sister like to see it when she comes to visit.

Hubble never disappoints, I wish they were going to keep it going, or bring it back, or something. I think it can still contribute allot.

It is said by most sources to be 2300 ly distant...but one interesting note....it is Approaching us...at 21 km/s...so, in the far distant future, we should be getting a better look. And maybe those remnant gases and elements will be reused in another star...

:---[===] *

Hmmm. "Approaching".
Yes, well.
2300 * 31,556,925.9936 /21 = 3,456,234,751.68 years to have Earth inside the big bubble. About two milliard years before its distance is only 700 Lys. By which time the bubble would appear thrice as large in our skies, had it not evaporated long before that.
"Space is big", Dr Lee.
Those bubbles don't tend to last very long. Certainly not milliards of years. So we can't wait for Brigid's Ring to come to us; if we want a good look we'll need Starships. Besides, we'd have to wait *four* milliard years or more to get a good look at the other side. (All calculations assume it's heading right at us which is extremely unlikely. Sol is *tiny*. And moving. )
Last night I watched a BBC3 (4?) program about the beautiful Voyagers. That "Pale Blue Dot" image is awesomely gorgeous and thought-provoking. It should be on the walls of every Parliament and Polling Station worldwide. Just as a hint.
( "Voyager: to the final frontier" ) .
Oh, feel free to correct my arithmetic if I've erred. Thanks.

[owlice]

Re football, get over it, people. Seriously. You're all clever enough to know what is meant here, and why should APOD trade one parochialism for what would be another to other readers? You didn't complain about the spelling of color, after all, which would be the same type of complaint as yours for football.

[Spoonsize]

looks like maybe a porthole to another universe. I've a vivid imagination at times.

[Tszabeau]

WOW!


Hmmm. "Approaching".
Yes, well.
2300 * 31,556,925.9936 /21 = 3,456,234,751.68 years to have Earth inside the big bubble. About two milliard years before its distance is only 700 Lys. By which time the bubble would appear thrice as large in our skies, had it not evaporated long before that.
"Space is big", Dr Lee.
Those bubbles don't tend to last very long. Certainly not milliards of years. So we can't wait for Brigid's Ring to come to us; if we want a good look we'll need Starships. Besides, we'd have to wait *four* milliard years or more to get a good look at the other side. (All calculations assume it's heading right at us which is extremely unlikely. Sol is *tiny*. And moving. )
Last night I watched a BBC3 (4?) program about the beautiful Voyagers. That "Pale Blue Dot" image is awesomely gorgeous and thought-provoking. It should be on the walls of every Parliament and Polling Station worldwide. Just as a hint.
( "Voyager: to the final frontier" ) .
Oh, feel free to correct my arithmetic if I've erred. Thanks.

I'm not a mathematician so excuse my ignorance but, does one milliard equal one million mallards?

[neufer]

---

Click to play embedded YouTube video.

Those bubbles don't tend to last very long.
Certainly not milliards of years.

I'm not a mathematician so excuse my ignorance but,
does one milliard equal one million mallards?

<<In British English (but not in American English), the word "billion" previously referred to a million millions (1,000,000,000,000). However, this is no longer the case, and the word is used unambiguously to mean one thousand million (1,000,000,000). The term milliard can also be used to refer to 1,000,000,000; variations on this name often appear in other languages (e.g. Spanish millardo, French milliard, German Milliarde or Russian миллиард).>>

<<Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium is the last book written by renowned American astronomer and science popularizer Carl Sagan before his death in 1996. To help viewers of Cosmos distinguish between "millions" and "billions", Sagan stressed the "b". Sagan never did, however, say "billions and billions". The public's association of the phrase and Sagan came from a Tonight Show skit. Parodying Sagan's affect, Johnny Carson quipped "billions and billions". The phrase has however now since become a humorous fictitious number—the Sagan.>>

[zbvhs]

I look at the Ring Nebula (so-called) and I don't see rings at all. "Rings" are those flat things orbiting Saturn. The Asteroid belt is relatively flat and might be seen as a "ring" around the Sun. The Ring Nebula doesn't appear to me to be flat at all. As has been noted, it appears to be roughly spheroidal in shape. What we see are the outer layers of the spheroid. The blue light is reflected from the back interior of the spheroid. The dark blobs are on what we see as the front side of the spheroid and are visible as such because they're back-lit by the central star. We see through the "hole" in the center because the material in the nebula is overall extremely tenuous. The dark blobs in the "hole" are an indication that the surface of the spheroid is more or less continuous. (It might be interesting to view the nebula in the wavelength for nitrogen or sulfur, if such be available. Any hint of red in the "hole" would indicate that the spheroid surface is continuous.) The material in the red "ring" is visible because we're seeing it edge-on. In other words, the spheroid surface is seen tangentially and we're looking through many millions of kilometers of "stuff". It's really not a flat structure that could be described as a "ring".

[Chris Peterson]

In other words, the spheroid surface is seen tangentially and we're looking through many millions of kilometers of "stuff". It's really not a flat structure that could be described as a "ring".

That was the view for a long time. But the new evidence demonstrates that is wrong. The Ring Nebula really is a ring (more precisely, a toroid). We're not seeing it the way we do because of the tangential view through a spherical body or shell.

The spherical components, found inside and outside the torus, are only visible with very long exposures using sensitive detectors. The only thing that anybody has ever seen through a telescope, or in most images, is the toroidal structure. The ring.

[neufer]

http://asterisk.apod.com/viewtopic.php? ... NG#p200538

[MargaritaMc]

Re football, get over it, people. Seriously. You're all clever enough to know what is meant here, and why should APOD trade one parochialism for what would be another to other readers? You didn't complain about the spelling of color, after all, which would be the same type of complaint as yours for football.

I don't think that it is the same kind of comment, Owlice.
Color/colour, like meter/metre, refers to the same thing under alternative spelling.
'Football' can refer to distinctly different shapes. (Rather in the way that 'pint' can refer to different quantities.)

And so, I suggest, is best either qualified with an adjective or avoided.

Margarita

[stephen63]

[owlice]

Margarita, that some on the other side of the pond are surprised or lament or complain about the use of common U.S. terminology on a site that is hosted on a U.S. Federal Government strikes me as silly at best. I would never think to suggest or complain about a UK site referring to something at "football-shaped" and meaning what we here would call a soccer ball, or referring to a lorry when we here would call such a vehicle a truck! I think it would be quite boorish of me to do so.

[geckzilla]

The problem is that we do not have a common word for "(American) football shaped". You could call it a prolate spheroid if you want but the layman isn't going to understand or remember that. Just like how there's no name for the front of your elbow. In anatomy it is of course called antecubital but again the layperson does not have a word for it so we can only describe it. There's a lot of things like that if you start looking for them.

[MargaritaMc]

The problem is that we do not have a common word for "(American) football shaped". You could call it a prolate spheroid if you want but the layman isn't going to understand or remember that. Just like how there's no name for the front of your elbow. In anatomy it is of course called antecubital but again the layperson does not have a word for it so we can only describe it. There's a lot of things like that if you start looking for them.

Would the word 'oval' do? Or does that only have the implication of being like an egg, with a big-end and a little-end?

And it is interesting how many things we don't have words for! In Spanish there are different words for the inside of a corner and the outside - and once you've begun using them you wonder how English manages with just the one word!
Margarita

[Anthony Barreiro]

...

...
The oldest football still in existence, which is thought to have been made circa 1540, was discovered in the roof of Stirling Castle, Scotland, in 1981. The ball is made of leather (possibly from a deer) and a pig's bladder. It has a diameter of between 14–16 cm (5.5–6.3 in), weighs 125 g (4.4 oz) and is currently on display at the Smith Art Gallery and Museum in Stirling.

The BBC have a photograph of this football
- and, as it can't be hotlinked, I've uploaded a copy here:

Oldest_football_1540.jpg

Margarita - also The Pedant

Has any effort been made to find the descendants of the lad (assuming it wasn't a lass) who kicked it up on the roof in the 1540's?

And I don't think it would be too onerous to describe a shape as "like an American football." As I was reminded when I wished everyone a happy Spring, apod and starship asterisk are read by people around the world (most of whom play association football, not our brutal American variant).