APOD: M16: Pillars of Creation (2012 Jul 22)

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by geckzilla » Sun Jul 22, 2012 10:36 pm

owlice wrote:
neufer wrote:He had no problem with faces, apparently.
Right; faces are easier to draw than hands.
Hands are as easy to draw as faces but most artists spend more time on faces. Regarding the Napoleon painting... given the adeptness of the rest of the painting it's impossible for me to believe his hand is in his jacket because the artist was unable or unwilling to paint the right hand. There are certainly other artists who hide hands and, even more often, feet, though.
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by neufer » Mon Jul 23, 2012 2:25 am

geckzilla wrote:
owlice wrote:
neufer wrote:He had no problem with faces, apparently.
Right; faces are easier to draw than hands.
Hands are as easy to draw as faces but most artists spend more time on faces. Regarding the Napoleon painting... given the adeptness of the rest of the painting it's impossible for me to believe his hand is in his jacket because the artist was unable or unwilling to paint the right hand. There are certainly other artists who hide hands and, even more often, feet, though.
http://en.wikipedia.org/wiki/Belisarius wrote: <<Flavius Belisarius (Greek: Βελισάριος, ca. 500 – 565) was a general of the Byzantine Empire. He was instrumental to Emperor Justinian's ambitious project of reconquering much of the Mediterranean territory of the former Western Roman Empire, which had been lost less than a century previously. He is also among a select group of men considered by historians to be the "Last of the Romans". According to a story that gained popularity during the Middle Ages, Justinian is said to have ordered Belisarius' eyes to be put out, and reduced him to the status of homeless beggar near the Pincian Gate of Rome, condemned to asking passers-by to "give an obolus to Belisarius" (date obolum Belisario), before pardoning him. Though the legend remains of dubious provenance, after the publication of Jean-François Marmontel's novel Bélisaire (1767), this account became a popular subject for progressive painters and their patrons in the later 18th century, who saw parallels between the actions of Justinian and the repression imposed by contemporary rulers. The most famous of these paintings, by Jacques-Louis David, combines the themes of charity (the alms giver), injustice (Belisarius), and the radical reversal of power (the soldier who recognises his old commander).>>
ImageImage
  • Thomas Gainsborough Self Portrait (1759)
http://vigilantcitizen.com/vigilantreport/the-hidden-hand-that-changed-history/ wrote: <<The initiation ritual to this Masonic degree re-enacts the return to Jerusalem of three Most Excellent Masons who were held captive in Babylon. The initiate is asked to learn a secret password and a hand sign in order to go through a series of veils as documented in Duncan’s Masonic Ritual and Monitor:

“Master of Second Veil: “Three Most Excellent Masters you must have been, or thus far you could not have come; but farther you cannot go without my words, sign, and word of exhortation. My words are Shem, Japhet, and Adoniram; my sign is this: (thrusting his hand in his bosom); it is in imitation of one given by God to Moses, when He commanded him to thrust his hand into his bosom, and, taking it out, it became as leprous as snow. My word of exhortation is explanatory of this sign, and is found in the writings of Moses, viz., fourth chapter of Exodus”- Duncan’s Masonic Ritual and Monitor

In Exodus 4:6, the heart (“bosom”) stands for what we are, the hand for what we do. It can thus be interpreted as : What we are is what we ultimately do. The symbolic significance of this gesture might explain the reason why it is so widely used by famous Masons. The hidden hand lets the other initiates know that the individual depicted is part of this secret Brotherhood and that his actions were inspired by the Masonic philosophy and beliefs. Furthermore, the hand that executes the actions is hidden behind cloth, which can symbolically refer to covert nature of the Mason’s actions. Here are some of the famous men who used this hand signal: George Washington, Franklin Pierce, Rutherford Hayes, and Teddy Roosevelt. We also have Karl Marx, Vladimir Lenin, and Joseph Stalin giving the sign, plus Napoleon, Salomon Rothschild, and many others.>>
http://en.wikipedia.org/wiki/Pledge_of_Allegiance wrote: <<The Pledge of Allegiance of the United States is an expression of loyalty to the federal flag and the republic of the United States of America, originally composed by Francis Bellamy in 1892. Swearing of the Pledge is accompanied by a salute. An early version of the salute, adopted in 1892, was known as the Bellamy salute. It started with the hand outstretched toward the flag, palm down, and ended with the palm up. Because of the similarity between the Bellamy salute and the Nazi salute, developed later, United States Congress instituted the hand-over-the-heart gesture as the salute to be rendered by civilians during the Pledge of Allegiance and the national anthem in the United States, instead of the Bellamy salute. Removal of the Bellamy salute occurred on December 22, 1942, when Congress amended the Flag Code language first passed into law on June 22, 1942.>>
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by owlice » Mon Jul 23, 2012 8:51 am

geckzilla wrote:Hands are as easy to draw as faces but most artists spend more time on faces. Regarding the Napoleon painting... given the adeptness of the rest of the painting it's impossible for me to believe his hand is in his jacket because the artist was unable or unwilling to paint the right hand. There are certainly other artists who hide hands and, even more often, feet, though.
Needed a smiley, I did; sorry! http://www.napoleon-series.org/faq/c_hand.html

Maybe it is a lack of practice, but hands do seem to be a problem for many to draw.
A closed mouth gathers no foot.

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Follow the money....

Post by neufer » Mon Jul 23, 2012 10:23 am

owlice wrote:
geckzilla wrote:Hands are as easy to draw as faces but most artists spend more time on faces. Regarding the Napoleon painting... given the adeptness of the rest of the painting it's impossible for me to believe his hand is in his jacket because the artist was unable or unwilling to paint the right hand. There are certainly other artists who hide hands and, even more often, feet, though.
Needed a smiley, I did; sorry! http://www.napoleon-series.org/faq/c_hand.html
http://www.napoleon-series.org/faq/c_hand.html wrote:
<<The painting by Jacques-Louis David (1748-1825), "Napoleon in his Study", the most famous expression of Napoleon in his classic pose, was not painted for the Emperor, but was commissioned by a Scottish nobleman, Alexander Douglas[-Hamilton], an admirer of Napoleon. Napoleon did not sit for the portrait, so David painted it from memory. Etienne Delecluze, a student and early biographer of David's, opined that the painting was a "poor likeness" and "too ideal." Napoleon, however, told the artist, "You have understood me, my dear David.">>
http://en.wikipedia.org/wiki/Napoleon_in_his_cabinet_de_travail wrote:
<<The Emperor Napoleon in His Study at the Tuileries is an 1812 painting by Jacques-Louis David. It was a private commission from the Scottish nobleman and admirer of Napoleon, Alexander Hamilton, 10th Duke of Hamilton in 1811 and completed in 1812. Originally shown at Hamilton Palace, it was sold to Archibald Primrose, 5th Earl of Rosebery in 1882, from whom it was bought by the Samuel H. Kress Foundation in 1954, which deposited it in Washington DC's National Gallery of Art, where it now hangs.>>
http://en.wikipedia.org/wiki/Alexander_Douglas-Hamilton,_10th_Duke_of_Hamilton wrote:
Image
<<Alexander Douglas-Hamilton, 10th Duke of Hamilton, 7th Duke of Brandon KG PC FRS FSA (3 October 1767 – 18 August 1852) was a Scottish politician and art collector. Born on 3 October 1767 at St James Square, London, a son of Archibald Hamilton, 9th Duke of Hamilton, he was educated at Christ Church, Oxford. [Hamilton] held the office of Grand Master of the Freemasons [Scotland] between 1820 and 1822. :D

Hamilton was a Whig, and his political career began in 1802, when he became MP for Lancaster. He remained in the House of Commons until 1806, when he was appointed to the Privy Council, and Ambassador to the court of St. Petersburg until 1807; additionally, he was Lord Lieutenant of Lanarkshire from 1802 to 1852. He received the numerous titles at his father's death in 1819. He was Lord High Steward at King William IV's coronation in 1831 and Queen Victoria's coronation in 1838, and remains the last person to have undertaken this duty twice. He became a Knight of the Garter in 1836.

Hamilton was a well-known dandy of his day. An obituary notice states that "timidity and variableness of temperament prevented his rendering much service to, or being much relied on by his party ... With a great predisposition to over-estimate the importance of ancient birth ... he well deserved to be considered the proudest man in England." He also supported Napoleon and commissioned the painting The Emperor Napoleon in His Study at the Tuileries by Jacques-Louis David.

Lord Lamington, in The Days of the Dandies, wrote of him that 'never was such a magnifico as the 10th Duke, the Ambassador to the Empress Catherine; when I knew him he was very old, but held himself straight as any grenadier. He was always dressed in a military laced undress coat, tights and Hessian boots, &c'. Lady Stafford in letters to her son mentioned 'his great Coat, long Queue, and Fingers cover'd with gold Rings', and his foreign appearance.

Hamilton had a strong interest in Ancient Egyptian mummies, and was so impressed with the work of mummy expert Thomas Pettigrew that he arranged for Pettigrew to mummify him after his death. He died on 18 August 1852 at age 84 and was buried on 4 September 1852 at Hamilton Palace, Hamilton, Scotland. In accordance with his wishes, Hamilton's body was mummified after his death and placed in a sarcophagus of the Ptolemaic period that he had originally acquired in Paris in 1836 ostensibly for the British Museum. At the same time he had acquired the sarcophagus of Pabasa, an important noblemen which is now in the Kelvingrove Museum.

His collection of paintings, objects, books and manuscripts was sold for £397,562 in July 1882. The manuscripts were purchased by the German government for £80,000. Some were repurchased by the British government and are now in the British Museum.>>
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by DavidLeodis » Mon Jul 23, 2012 10:49 am

On clicking the "famous image" link I found I cannot view the documentation unless I pay for that Information. :!:

Is that the situation for anyone else or is it just a problem somehow with my browser? If it is what others get then I hope the APOD are not starting down the road to having to pay to see APODs.

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by RJN » Mon Jul 23, 2012 1:39 pm

DavidLeodis wrote:On clicking the "famous image" link I found I cannot view the documentation unless I pay for that Information. :!:

Is that the situation for anyone else or is it just a problem somehow with my browser? If it is what others get then I hope the APOD are not starting down the road to having to pay to see APODs.
I embedded that link from my office at Michigan Tech, where it worked for free. I was hoping that it worked everywhere for free, but I see now that is not the case. If anyone can find the same content that is (legally of course) out from behind a pay wall, I will replace the link. I apologize for the oversight.

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by DavidLeodis » Mon Jul 23, 2012 4:39 pm

RJN wrote:
DavidLeodis wrote:On clicking the "famous image" link I found I cannot view the documentation unless I pay for that Information. :!:

Is that the situation for anyone else or is it just a problem somehow with my browser? If it is what others get then I hope the APOD are not starting down the road to having to pay to see APODs.
I embedded that link from my office at Michigan Tech, where it worked for free. I was hoping that it worked everywhere for free, but I see now that is not the case. If anyone can find the same content that is (legally of course) out from behind a pay wall, I will replace the link. I apologize for the oversight.

- RJN
Thank you RJN (Robert Nemiroff :?: ) for your reply. I much appreciate you taking time out to respond during what I am sure must be a very busy schedule. :)

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by NoelC » Tue Jul 24, 2012 8:11 am

smitty wrote:The discussion section of this apod puzzles me; it says:

"The pillars of creation were imaged again in 2007 by the orbiting Spitzer Space Telescope in infrared light, leading to the conjecture that the pillars may already have been destroyed by a local supernova, but light from that event has yet to reach the Earth."

Am I reading this wrong, or is it somehow implying that infrared radiation travels faster than visible radiation? Some clarification would be much appreciated. Thanks.
It sees to me that if we can't see it yet then it hasn't happened yet. In my mind a relativistic "universe view" is the only one that can make any sense.

The human imagination keeps trying to exceed the speed of light, but 186,282 miles/second isn't just a good idea - it's the law.

Neufer has so far eluded the cops.

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by neufer » Tue Jul 24, 2012 8:51 am

smitty wrote:
The discussion section of this apod puzzles me; it says:

"The pillars of creation were imaged again in 2007 by the orbiting Spitzer Space Telescope in infrared light, leading to the conjecture that the pillars may already have been destroyed by a local supernova, but light from that event has yet to reach the Earth."

Am I reading this wrong, or is it somehow implying that infrared radiation travels faster than visible radiation? Some clarification would be much appreciated. Thanks.
We don't know if the evaporating Pillars of Creation of 7,000 years ago have survived to the present day.

However, Spitzer observed that they are sitting in a warm bath of supernova remnant; hence they have probably all melted away by now.
NoelC wrote:
It sees to me that if we can't see it yet then it hasn't happened yet. In my mind a relativistic "universe view" is the only one that can make any sense.

The human imagination keeps trying to exceed the speed of light, but 186,282 miles/second isn't just a good idea - it's the law.

Neufer has so far eluded the cops.
It probably has something to do with faulty wiring.
http://asterisk.apod.com/viewtopic.php? ... 39#p170239
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Chris Peterson » Tue Jul 24, 2012 2:11 pm

NoelC wrote:It sees to me that if we can't see it yet then it hasn't happened yet. In my mind a relativistic "universe view" is the only one that can make any sense.
I also think this is the best way to look at it. But it's not the only one that makes sense- that depends on how you define "now"- a not-so-simple concept at all. But in general, trying to disentangle time and space to figure out whether an event has occurred at a point in spacetime we are causally disconnected from serves little purpose, and usually leads to confusion.
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by neufer » Tue Jul 24, 2012 2:58 pm

Chris Peterson wrote:
NoelC wrote:
It sees to me that if we can't see it yet then it hasn't happened yet. In my mind a relativistic "universe view" is the only one that can make any sense.
I also think this is the best way to look at it. But it's not the only one that makes sense- that depends on how you define "now"- a not-so-simple concept at all. But in general, trying to disentangle time and space to figure out whether an event has occurred at a point in spacetime we are causally disconnected from serves little purpose, and usually leads to confusion.
Which is an excellent argument for putting the edge of the observable universe at a distance of either:
  • 1) ~13.75 billion light-years or
    2) ~16 billion light-years (see below)
as opposed to 46–47 billion light-years.
http://en.wikipedia.org/wiki/Observable_universe wrote:
<<In Big Bang cosmology, the observable universe consists of the galaxies and other matter that humans can in principle observe from Earth in the present day, because light (or other signals) from those objects has had time to reach us since the beginning of the cosmological expansion. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction—that is, the observable universe is a spherical volume (a ball) centered on the observer, regardless of the shape of the universe as a whole. Every location in the universe has its own observable universe which may or may not overlap with the one centered on the Earth.

The word observable used in this sense does not depend on whether modern technology actually permits detection of radiation from an object in this region (or indeed on whether there is any radiation to detect). It simply indicates that it is possible in principle for light or other signals from the object to reach an observer on Earth. In practice, we can see light only from as far back as the time of photon decoupling in the recombination epoch, which is when particles were first able to emit photons that were not quickly re-absorbed by other particles, before which the universe was filled with a plasma opaque to photons. The collection of points in space at just the right distance so that photons emitted at the time of photon decoupling would be reaching us today form the surface of last scattering, and the photons emitted at the surface of last scattering are the ones we detect today as the cosmic microwave background radiation (CMBR). However, it may be possible in the future to observe the still older neutrino background, or even more distant events via gravitational waves (which also move at the speed of light). Sometimes a distinction is made between the visible universe, which includes only signals emitted since recombination, and the observable universe, which includes signals since the beginning of the cosmological expansion (the Big Bang in traditional cosmology, the end of the inflationary epoch in modern cosmology). The comoving distance (current proper distance) to the particles which emitted the CMBR, representing the radius of the visible universe, is calculated to be about 14.0 billion parsecs (about 45.7 billion light years), while the comoving distance to the edge of the observable universe is calculated to be 14.3 billion parsecs (about 46.6 billion light years), about 2% larger.

The age of the universe is about 13.75 billion years, but due to the expansion of space humans are observing objects that were originally much closer but are now considerably farther away (as defined in terms of cosmological proper distance, which is equal to the comoving distance at the present time) than a static 13.75 billion light-years distance. The diameter of the observable universe is estimated to be about 28 billion parsecs (93 billion light-years), putting the edge of the observable universe at about 46–47 billion light-years away.

Some parts of the universe may simply be too far away for the light emitted from there at any moment since the Big Bang to have had enough time to reach Earth at present, so these portions of the universe would currently lie outside the observable universe. In the future the light from distant galaxies will have had more time to travel, so some regions not currently observable will become observable in the future. However, due to Hubble's law regions sufficiently distant from us are expanding away from us much faster than the speed of light (special relativity prevents nearby objects in the same local region from moving faster than the speed of light with respect to each other, but there is no such constraint for distant objects when the space between them is expanding), and the expansion rate appears to be accelerating due to dark energy. Assuming dark energy remains constant (an unchanging cosmological constant), so that the expansion rate of the universe continues to accelerate, there is a "future visibility limit" beyond which objects will never enter our observable universe at any time in the infinite future, because light emitted by objects outside that limit can never reach points that are expanding away from us at less than the speed of light (a subtlety here is that because the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from us just a bit faster than light does manage to emit a signal which reaches us eventually). This future visibility limit is calculated to be at a comoving distance of 19 billion parsecs (62 billion light years), which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, as discussed in the following paragraph) is only larger than the number currently observable by a factor of 2.36.

Though in principle more galaxies will become observable in the future, in practice an increasing number of galaxies will become extremely redshifted due to ongoing expansion, so much so that they will seem to disappear from view and become invisible. An additional subtlety is that a galaxy at a given comoving distance is defined to lie within the "observable universe" if we can receive signals emitted by the galaxy at any age in its past history (say, a signal sent from the galaxy only 500 million years after the Big Bang), but because of the universe's expansion, there may be some later age at which a signal sent from the same galaxy will never be able to reach us at any point in the infinite future (so for example we might never see what the galaxy looked like 10 billion years after the Big Bang), even though it remains at the same comoving distance (comoving distance is defined to be constant with time, unlike proper distance which is used to define recession velocity due to the expansion of space) which is less than the comoving radius of the observable universe. This fact can be used to define a type of cosmic event horizon whose distance from us changes over time; for example, the current distance to this horizon is about 16 billion light years, meaning that a signal from an event happening at present would eventually be able to reach us in the future if the event was less than 16 billion light years away, but the signal would never reach us if the event was more than 16 billion light years away.

Both popular and professional research articles in cosmology often use the term "universe" to mean "observable universe". This can be justified on the grounds that we can never know anything by direct experimentation about any part of the universe that is causally disconnected from us, although many credible theories require a total universe much larger than the observable universe. No evidence exists to suggest that the boundary of the observable universe constitutes a boundary on the universe as a whole, nor do any of the mainstream cosmological models propose that the universe has any physical boundary in the first place, though some models propose it could be finite but unbounded, like a higher-dimensional analogue of the 2D surface of a sphere which is finite in area but has no edge. It is plausible that the galaxies within our observable universe represent only a minuscule fraction of the galaxies in the universe. According to the theory of cosmic inflation and its founder, Alan Guth, if it is assumed that inflation began about 10−37 seconds after the Big Bang, then with the plausible assumption that the size of the universe at this time was approximately equal to the speed of light times its age, that would suggest that at present the entire universe's size is at least 1023 times larger than the size of the observable universe.

If the universe is finite but unbounded, it is also possible that the universe is smaller than the observable universe. In this case, what we take to be very distant galaxies may actually be duplicate images of nearby galaxies, formed by light that has circumnavigated the universe. It is difficult to test this hypothesis experimentally because different images of a galaxy would show different eras in its history, and consequently might appear quite different. Vaudrevange et al: Constraints on the Topology of the Universe: Extension to General Geometries claims to establish a lower bound of 26 gigaparsecs (85 billion light-years) on the diameter of the whole universe, meaning the smallest possible diameter for the whole universe would be 98.5% of the diameter of the last scattering surface (since this is only a lower bound, the paper leaves open the possibility that the whole universe is much larger, even infinite). This value is based on matching-circle analysis of the WMAP 7 year data; this approach has been disputed.>>
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Chris Peterson » Tue Jul 24, 2012 3:27 pm

neufer wrote:Which is an excellent argument for putting the edge of the observable universe at a distance of either:
  • 1) ~13.75 billion light-years or
    2) ~16 billion light-years (see below)
as opposed to 46–47 billion light-years.
I see the better argument of using the comoving distance, 46 billion ly, because it makes it easier to visualize the actual expansion of the Universe. Using the light time distance fails completely in that respect.

But in any case, it again comes down to properly defining your terms. If you set up the question properly, any of these distances is correct... just as different concepts of "now" are correct. But you need the assumptions defined, or you just have confusion.
Chris

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by neufer » Tue Jul 24, 2012 4:26 pm

Chris Peterson wrote:
neufer wrote:
Which is an excellent argument for putting the edge of the observable universe at a distance of either:
  • 1) ~13.75 billion light-years or
    2) ~16 billion light-years (see below)
as opposed to 46–47 billion light-years.
I see the better argument of using the comoving distance, 46 billion ly, because it makes it easier to visualize the actual expansion of the Universe. Using the light time distance fails completely in that respect.

But in any case, it again comes down to properly defining your terms. If you set up the question properly, any of these distances is correct... just as different concepts of "now" are correct. But you need the assumptions defined, or you just have confusion.
There has certainly got to be a better term than the observable universe seeing as how:
  • 1) None of is observable as it exists today.
    2) The part beyond the CMBR has yet to be observed.
    3) The part of it beyond ~16 billion light-years will never be observed.
Why not refer to it as the known universe :?:
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Chris Peterson » Tue Jul 24, 2012 4:40 pm

neufer wrote:There has certainly got to be a better term than the observable universe seeing as how:
  • 1) None of is observable as it exists today.
    2) The part beyond the CMBR has yet to be observed.
    3) The part of it beyond ~16 billion light-years will never be observed.
Why not refer to it as the known universe :?:
I think "observable Universe" is perfect, since it describes the part of the Universe we can actually observe. Besides, "known universe" is owned by Larry Niven.
Chris

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by neufer » Tue Jul 24, 2012 6:21 pm

Chris Peterson wrote:
neufer wrote:
There has certainly got to be a better term than the observable universe seeing as how:
  • 1) None of is observable as it exists today.
    2) The part beyond the CMBR has yet to be observed.
    3) The part of it beyond ~16 billion light-years will never be observed.
Why not refer to it as the known universe :?:
I think "observable Universe" is perfect, since it describes the part of the Universe we can actually observe.
  • But it doesn't at all! (see above)
Chris Peterson wrote:
Besides, "known universe" is owned by Larry Niven.

  • As I was walkin' - I saw a sign there
    And that sign said - no tress passin'
    But on the other side .... it didn't say nothin!
    Now that side was made for you and me!
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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by NoelC » Wed Jul 25, 2012 3:05 am

Chris Peterson wrote:in general, trying to disentangle time and space to figure out whether an event has occurred at a point in spacetime we are causally disconnected from serves little purpose, and usually leads to confusion.
Therein lies the rub. We are causally connected. We observe things out there because the light has brought the information to us and this causes things to happen - for example this discussion.

Think too hard on this stuff and you start to realize that the future must be hard set, and you have to begin to believe in destiny. Inasmuch as we can traverse the 3 spatial dimensions, since observers at different points in space-time are "seeing" things at various stages of progress through the time dimension, it implies the time dimension is no different. We just perceive it as different because our very capability for perception is locked to its very passing.

I think the inevitable result of such thought has to be things along the lines of:

Whatever will be will be.

-and-

Don't worry; be happy!

:D

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Beyond » Wed Jul 25, 2012 3:20 am

Very scientific and most logical.
To find the Truth, you must go Beyond.

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Strangerbarry » Mon Jul 30, 2012 3:49 pm

The hyperlink for EGGs takes you to the Wikipedia article on eggs - i.e. birg and reptile eggs !

Strangerbarry

Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Strangerbarry » Mon Jul 30, 2012 3:59 pm

I was surprised by the line: "leading to the conjecture that the pillars may already have been destroyed by a local supernova". This is the first time I've ever seen a reference in an astronomy article to the "present" meaning OUR present moment applied to somewhere OUT THERE - usually the "present" is treated as the light we presently see - and explaining the fact that the light takes whatever number of years to reach us yadayadayada. The idea of ourselves here sharing a present moment with any distant location out there in outer space is highly problematic - there really is no single present moment that applies across the universe even allowing for the time it takes light to reach us - no universally applicable "now", because Einstein showed that time passes more slowly near massive objects - within the event horizon of a black hole, time is believed to stop altogether - the rate of time's passing is a local phenomenon.

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by bystander » Mon Jul 30, 2012 4:04 pm

Strangerbarry wrote:The hyperlink for EGGs takes you to the Wikipedia article on eggs - i.e. birg and reptile eggs !
I'm not sure that was a mistake. It may possibly be humor from the editors. Perhaps you were expecting this.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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Re: APOD: M16: Pillars of Creation (2012 Jul 22)

Post by Chris Peterson » Mon Jul 30, 2012 5:19 pm

Strangerbarry wrote:I was surprised by the line: "leading to the conjecture that the pillars may already have been destroyed by a local supernova". This is the first time I've ever seen a reference in an astronomy article to the "present" meaning OUR present moment applied to somewhere OUT THERE - usually the "present" is treated as the light we presently see - and explaining the fact that the light takes whatever number of years to reach us yadayadayada. The idea of ourselves here sharing a present moment with any distant location out there in outer space is highly problematic - there really is no single present moment that applies across the universe even allowing for the time it takes light to reach us - no universally applicable "now", because Einstein showed that time passes more slowly near massive objects - within the event horizon of a black hole, time is believed to stop altogether - the rate of time's passing is a local phenomenon.
This was discussed earlier in the thread.

The attempt to map distant time to our local frame is common in popular astronomical writing. I think authors use it as a tool to engage their readers. You'll rarely if ever see something like this in a scholarly publication, however.

There's no need to involve GR, however. The effect of mass on time is insignificantly small in virtually all cases, and certainly is irrelevant in this image. We need only concern ourselves with the much simpler SR formulation of spacetime (often modeled as a framework of meter sticks and clocks) to understand the difficulties of comparing "now" here to "now" somewhere else.
Chris

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