APOD and General Astronomy Discussion Forum
https://asterisk.apod.com/
It's a beautiful picture that puts the nebula in a new light. I hope it's in the queue for a future apod.starsurfer wrote: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/
I think it's a donut.stephen63 wrote: Is it not a ring?
Well, curiouser and curiouser, as Alice ungrammatically said. Wikipedia says it was found on the roof, but The Beeb says that it wasAnthony Barreiro wrote: 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?
So, it could have been kicked by The Lassie hersel'... discovered behind the paneling of the Queen's Chamber in Stirling Castle, which was decorated in the 1540's.
Mary Queen of Scots was there at this time and later in life was known to have an interest in all sports but especially golf and football. She recorded a game of football in her diaries while at Carlisle Castle.
The ball could have been used in the courtyards within the castle or taken to the royal gardens below the walls. Everyone from the castle, including kings and queens would have been involved. Football was a game for all just as it is today.
Was this personal item, belonging to Mary, deliberately placed behind the paneling to act as a protection from witchcraft, a practice common at the time or was it somehow lost. We will never answer that question but we do know that this little ball is the beginning of a sport that now involves a sixth of the population of the world.
.See the videos @ http://asterisk.apod.com/viewtopic.php?t=31431Ann wrote:I think it's a donut.stephen63 wrote: Is it not a ring?
Ask Rob.
Ann
Chris Peterson wrote: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.zbvhs wrote: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".
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.
It is indicative of a temperature gradient:JohnD wrote:
How do the different elements become so stratified in the nebula. so as to produce the gradation of colour?
http://hubblesite.org/newscenter/archive/releases/1999/01/image/a/ wrote:
<<The colors are approximately true colors. The color image was assembled from three black-and-white photos taken through different color filters with the Hubble telescope's Wide Field Planetary Camera 2. Blue isolates emission from very hot helium, which is located primarily close to the hot central star. Green represents ionized oxygen, which is located farther from the star. Red shows ionized nitrogen, which is radiated from the coolest gas, located farthest from the star. The gradations of color illustrate how the gas glows because it is bathed in ultraviolet radiation from the remnant central star, whose surface temperature is a white-hot 120,000 degrees Celsius.>>
There may be a degree of actual stratification caused by physical processes, but mostly what you're seeing are different areas selectively ionized. Gases with high ionization energies are glowing near the center; those with lower energies glow further out. You're seeing an energy gradient more than a material one.JohnD wrote:Now. Can anyone answer my rider question, which I repeat?
How do the different elements become so stratified in the nebula. so as to produce the gradation of colour?
Whose "national sensibilities"? Yours? Seems those are the only ones you're taking into account. Bah! So long as I could insist that British government sources qualify their use of "football shaped" to indicate they mean spherical, that'd be just dandy, but I suspect you and others would think it quite cheeky of me to do so.JohnD wrote:owlice,
if it had been described as "American-football shaped" all would be clear, and national sensibilities would be satisfied.
To call this object football shaped is just misleading, in many parts of the world that are vastly and wonderfully informed by APOD.
neufer wrote:Looking Down a Barrel of Gas at a Doomed Star wrote:
<<The colors are approximately true colors. The color image was assembled from three black-and-white photos taken through different color filters with the Hubble telescope's Wide Field Planetary Camera 2. Blue isolates emission from very hot helium, which is located primarily close to the hot central star. Green represents ionized oxygen, which is located farther from the star. Red shows ionized nitrogen, which is radiated from the coolest gas, located farthest from the star. The gradations of color illustrate how the gas glows because it is bathed in ultraviolet radiation from the remnant central star, whose surface temperature is a white-hot 120,000 degrees Celsius.>>
owlice wrote: Please know there are plenty of people in the Americas who complain about the use of American as a designation for something pertaining to just the U.S.
owlice,owlice wrote:Whose "national sensibilities"? Yours? Seems those are the only ones you're taking into account. Bah! So long as I could insist that British government sources qualify their use of "football shaped" to indicate they mean spherical, that'd be just dandy, but I suspect you and others would think it quite cheeky of me to do so.JohnD wrote:owlice,
if it had been described as "American-football shaped" all would be clear, and national sensibilities would be satisfied.
To call this object football shaped is just misleading, in many parts of the world that are vastly and wonderfully informed by APOD.
If your "national sensibilities" are offended by U.S. vocabulary on a site hosted by the U.S. Government, I suggest you stick to UK sources.
Please know there are plenty of people in the Americas who complain about the use of American as a designation for something pertaining to just the U.S. Of course their "national sensibilities" may not matter to you, either!
APOD Robot wrote: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 an American 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. >>
There's a big difference between something being a "mistake" and recognizing that a choice of wording might have been less than clear to some people. Alternate captions can be proposed for most APODs, which doesn't mean that those actually used represent mistakes.JohnD wrote:It was a mistake for such an eminent and valuable site as APOD to use the 'football' comparison when the addition of the single word "American" would have made the comparison clear.
You are not imagining us at all. Someday maybe we will meet in person.Spoonsize wrote:looks like maybe a porthole to another universe. I've a vivid imagination at times.
Nope. They were English, more or less, the progeny of American fathers and English Moms, and were raised in England -- though two of the three members were born in the US. Wikipedia says, "Eventually the trio dubbed themselves America, chosen because they did not want anyone to think they were British musicians trying to sound American."BillBixby wrote: As I recall the singing group America was formed in Canada.
