APOD: Along the Western Veil (2019 Sep 19)

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Expand view Topic review: APOD: Along the Western Veil (2019 Sep 19)

Re: APOD: Along the Western Veil (2019 Sep 19)

by MarkBour » Sat Sep 21, 2019 10:41 pm

Ann wrote: Thu Sep 19, 2019 4:21 pm
FLPhotoCatcher wrote: Thu Sep 19, 2019 6:29 am
wolfie138 wrote: Thu Sep 19, 2019 6:14 am Looks like a crocodile.
To me, it looks more like the traditional depiction of the devil.
Look at this (great) picture of the entire Veil Nebula, the western part at right, the eastern part at left. Look at the eastern part. Can you see that it looks like an evil, grinning man (or worse)? Can you see his forehead at top, then his nose, then his horribly grinning slightly greenish mouth, and finally his chin.

Gaaah!!! The eastern part of the Veil Nebula looks about as evil as the Pleiades look sweet and lovely.

Ann
Capture.PNG
Capture.PNG (958 Bytes) Viewed 5232 times
Yep. It's just rotation and perspective:

:mrgreen:

(consider looking at the letters from the two perspectives, a and b.
And from view a, you can either crop out the D or not, depending
on your preference.)

Re: APOD: Along the Western Veil (2019 Sep 19)

by orin stepanek » Thu Sep 19, 2019 10:29 pm

Chris Peterson wrote: Thu Sep 19, 2019 6:17 pm
orin stepanek wrote: Thu Sep 19, 2019 6:12 pm Don't understand why it's confusing? Simple math! 5000 years ago + 1500 years distant = 6500 years ago event took place! :roll:
It's confusing because that's not what Art is saying, and it's not how Art is getting the 6500 year number.

See, your response just demonstrates my point that his was confusing!
Oh! :shock: Shows how 'not smart ' I am!

Re: APOD: Along the Western Veil (2019 Sep 19)

by Chris Peterson » Thu Sep 19, 2019 8:42 pm

MarkBour wrote: Thu Sep 19, 2019 8:39 pm
neufer wrote: Thu Sep 19, 2019 7:41 pm ...
The important issues are:
  • 1) when it might have been observed on Earth.
    2) what is the evolutionary age of the observed remnant.
    3) how can the supernova easily be named & identified.
There are a few more ... 8-)
But the first two, and a lesser degree the third, are the important ones related to timing.

Re: APOD: Along the Western Veil (2019 Sep 19)

by MarkBour » Thu Sep 19, 2019 8:39 pm

neufer wrote: Thu Sep 19, 2019 7:41 pm ...
The important issues are:
  • 1) when it might have been observed on Earth.
    2) what is the evolutionary age of the observed remnant.
    3) how can the supernova easily be named & identified.

There are a few more ... 8-)

Re: APOD: Along the Western Veil (2019 Sep 19)

by DL MARTIN » Thu Sep 19, 2019 8:11 pm

I prefer infer to observe since it more accurately specifies that what we are speculating about is in the past. Although current events are media friendly and marketable, the fact that what is happening in the Universe is yesterday's news. I enjoy astronomy but I prefer scientific integrity even more.

Re: APOD: Along the Western Veil (2019 Sep 19)

by neufer » Thu Sep 19, 2019 7:41 pm

orin stepanek wrote: Thu Sep 19, 2019 6:12 pm
Don't understand why it's confusing?
Simple math! 5000 years ago + 1500 years distant = 6500 years ago event took place! :roll:
No scientist really cares when a supernova took place in THAT sense.

The important issues are:
  • 1) when it might have been observed on Earth.
    2) what is the evolutionary age of the observed remnant.
    3) how can the supernova easily be named & identified.
Apparently, you don't care very much if SN 1987A is designated SN -166,013 (with endless future modifications of that designation then being necessary) but most practicing scientists do care. Such folks generally don't bother to stipulate the absolute age of objects that also live in the same absolute age related physical environs as ourselves (unless they are time syncing light vs neutrinos vs gravitational waves).
https://en.wikipedia.org/wiki/SN_1987A wrote:
<<SN 1987A was a type II supernova in the Large Magellanic Cloud, a dwarf galaxy satellite of the Milky Way. It occurred approximately 51.4 kiloparsecs (168,000 light-years) from Earth and was the closest observed supernova since Kepler's Supernova, visible from earth in 1604.>>
https://en.wikipedia.org/wiki/Supernova#Naming_convention wrote:
<<Supernova discoveries are reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams, which sends out a circular with the name it assigns to that supernova. The name is formed from the prefix SN, followed by the year of discovery, suffixed with a one or two-letter designation. The first 26 supernovae of the year are designated with a capital letter from A to Z. Afterward pairs of lower-case letters are used: aa, ab, and so on. Hence, for example, SN 2003C designates the third supernova reported in the year 2003. The last supernova of 2005, SN 2005nc, was the 367th (14 × 26 + 3 = 367). The suffix "nc" acts as a bijective base-26 encoding, with a = 1, b = 2, c = 3, ... z = 26. Since 2000, professional and amateur astronomers have been finding several hundreds of supernovae each year (572 in 2007, 261 in 2008, 390 in 2009; 231 in 2013).

Historical supernovae are known simply by the year they occurred: SN 185, SN 1006, SN 1054, SN 1572 (called Tycho's Nova) and SN 1604 (Kepler's Star). Since 1885 the additional letter notation has been used, even if there was only one supernova discovered that year (e.g. SN 1885A, SN 1907A, etc.) — this last happened with SN 1947A. SN, for SuperNova, is a standard prefix. Until 1987, two-letter designations were rarely needed; since 1988, however, they have been needed every year. >>

Re: APOD: Along the Western Veil (2019 Sep 19)

by Chris Peterson » Thu Sep 19, 2019 6:17 pm

orin stepanek wrote: Thu Sep 19, 2019 6:12 pm Don't understand why it's confusing? Simple math! 5000 years ago + 1500 years distant = 6500 years ago event took place! :roll:
It's confusing because that's not what Art is saying, and it's not how Art is getting the 6500 year number.

See, your response just demonstrates my point that his was confusing!

Re: APOD: Along the Western Veil (2019 Sep 19)

by orin stepanek » Thu Sep 19, 2019 6:12 pm

Don't understand why it's confusing? Simple math! 5000 years ago + 1500 years distant = 6500 years ago event took place! :roll:

Re: APOD: Along the Western Veil (2019 Sep 19)

by Visual_Astronomer » Thu Sep 19, 2019 5:07 pm

The Veil is absolutely my favorite visual target. A narrow-band filter brings out all the twists and filaments that one can see in the photos. It is one of the view visual targets that actually looks like the photos.

Re: APOD: Along the Western Veil (2019 Sep 19)

by neufer » Thu Sep 19, 2019 4:55 pm

Chris Peterson wrote: Thu Sep 19, 2019 3:34 pm
DL MARTIN wrote: Thu Sep 19, 2019 3:30 pm
How can we observe 5,000 years of evolution? We are observing the change from 1784 till now - if at all.
We can see the current state, which includes information about the speed and direction components are moving. That allows us to model the structure backwards in time, which is where the timing to the actual supernova comes from.

We observe the evolution of all sorts of things despite our inability to directly see things in the past.

Would you prefer infer the evolution? That's what "observe" is generally taken to mean in this context.

Re: APOD: Along the Western Veil (2019 Sep 19)

by Ann » Thu Sep 19, 2019 4:21 pm

FLPhotoCatcher wrote: Thu Sep 19, 2019 6:29 am
wolfie138 wrote: Thu Sep 19, 2019 6:14 am Looks like a crocodile.
To me, it looks more like the traditional depiction of the devil.
Look at this (great) picture of the entire Veil Nebula, the western part at right, the eastern part at left. Look at the eastern part. Can you see that it looks like an evil, grinning man (or worse)? Can you see his forehead at top, then his nose, then his horribly grinning slightly greenish mouth, and finally his chin.

Gaaah!!! The eastern part of the Veil Nebula looks about as evil as the Pleiades look sweet and lovely.

Ann

Re: APOD: Along the Western Veil (2019 Sep 19)

by Chris Peterson » Thu Sep 19, 2019 3:34 pm

DL MARTIN wrote: Thu Sep 19, 2019 3:30 pm How can we observe 5,000 years of evolution? We are observing the change from 1784 till now - if at all.
We can see the current state, which includes information about the speed and direction components are moving. That allows us to model the structure backwards in time, which is where the timing to the actual supernova comes from.

We observe the evolution of all sorts of things despite our inability to directly see things in the past. Would you prefer infer the evolution? That's what "observe" is generally taken to mean in this context.

Re: APOD: Along the Western Veil (2019 Sep 19)

by DL MARTIN » Thu Sep 19, 2019 3:30 pm

How can we observe 5,000 years of evolution? We are observing the change from 1784 till now - if at all.

Re: APOD: Along the Western Veil (2019 Sep 19)

by neufer » Thu Sep 19, 2019 2:49 pm

Click to play embedded YouTube video.
Chris Peterson wrote: Thu Sep 19, 2019 2:06 pm
Well now you've confused a lot of people!
It's a dirty job but someone's got to do it. :incredulous:

Re: APOD: Along the Western Veil (2019 Sep 19)

by Chris Peterson » Thu Sep 19, 2019 2:06 pm

neufer wrote: Thu Sep 19, 2019 2:02 pm
Chris Peterson wrote: Thu Sep 19, 2019 1:35 pm
orin stepanek wrote: Thu Sep 19, 2019 1:15 pm
The Veil's light reached Earth 5000 years ago; and is 1500 Light years away! Can I presume that this event happened 6500 years ago? :?:
If you want. But that's not useful in any way. The only value that is useful is treating this event as having happened 5000 years ago. We're observing 5000 years of the evolution of a supernova, not 6500 years.
Actually...
the "observation" would have taken place between 5000 and 8000 years ago
so 6500 years of evolution is the average best guess at this time.
Well now you've confused a lot of people!

Re: APOD: Along the Western Veil (2019 Sep 19)

by neufer » Thu Sep 19, 2019 2:02 pm

Chris Peterson wrote: Thu Sep 19, 2019 1:35 pm
orin stepanek wrote: Thu Sep 19, 2019 1:15 pm
The Veil's light reached Earth 5000 years ago; and is 1500 Light years away! Can I presume that this event happened 6500 years ago? :?:
If you want. But that's not useful in any way. The only value that is useful is treating this event as having happened 5000 years ago. We're observing 5000 years of the evolution of a supernova, not 6500 years.
Actually...
the "observation" would have taken place between 5000 and 8000 years ago
so 6500 years of evolution is the average best guess at this time.

Re: APOD: Along the Western Veil (2019 Sep 19)

by Chris Peterson » Thu Sep 19, 2019 1:35 pm

orin stepanek wrote: Thu Sep 19, 2019 1:15 pm The Veil's light reached Earth 5000 years ago; and is 1500 Light years away! Can I presume that this event happened 6500 years ago? :?:
If you want. But that's not useful in any way. The only value that is useful is treating this event as having happened 5000 years ago. We're observing 5000 years of the evolution of a supernova, not 6500 years.

Re: APOD: Along the Western Veil (2019 Sep 19)

by orin stepanek » Thu Sep 19, 2019 1:15 pm

The Veil's light reached Earth 5000 years ago; and is 1500 Light years away! Can I presume that this event happened 6500 years ago? :?:

Re: APOD: Along the Western Veil (2019 Sep 19)

by neufer » Thu Sep 19, 2019 12:42 pm

https://en.wikipedia.org/wiki/Nebulae_in_fiction#Veil_Nebula wrote:
<<The Veil Nebula is one component of the large but relatively faint spherical residue of a supernova that exploded some 5 to 8 thousand years ago. Discovered in 1784 by William Herschel, the remnant appears to human observers as a braid of thread-like strands. The standard interpretation is that the shock waves defining its surface are so attenuated that the shell is visible only when viewed edge-on, giving it the appearance of a collection of filaments.
----------------------------------------------------------
Dark Star (1974), film written by John Carpenter and Dan O'Bannon, and directed by Carpenter. The scout ship Dark Star[ship Asterisk*] and its bored, eccentric crew wander the universe, armed with sentient "thermostellar" bombs:

In the mid-22nd century, mankind has begun colonizing the far reaches of the universe. Armed with artificially intelligent "Thermostellar Triggering Devices," the scout ship Dark Star[ship Asterisk*] and its crew have been alone in space for 20 years on a mission to destroy "unstable planets" which might threaten future colonization of other planets.

The ship is in a state of deterioration and there are frequent system malfunctions (for example, an irreparable radiation leak, their cargo of intelligent talking bombs lowering from their bomb bay without a command to do so, and an explosion destroying their sleeping quarters), and only the voice of the ship's computer for company. The Dark Star[ship Asterisk*]′s commanding officer, Commander Powell, was killed during hyperdrive as a result of an electrical short-circuit behind his rear seat panel, but remains aboard the ship in a state of cryogenic suspension. The ship's remaining crew consists of its new commanding officer, Lieutenant Doolittle (helmsman, and originally second-in-command), Sergeant Pinback (bombardier), Corporal Boiler (navigator), and Talby (target specialist). As the tedium of their tasks over 20 years has driven them "around the bend", they have created distractions for themselves: Doolittle, formerly a surfer from Malibu, California, has constructed a musical bottle organ; Talby spends his time in the ship's observation dome, content to watch the universe go by; Boiler obsessively trims his moustache, smokes cigars, and shoots targets with the ship's emergency laser rifle in a corridor. Pinback plays practical jokes on the crew members, maintains a video diary, and has adopted a ship's mascot in the form of a mischievous "beach ball"-like alien who refuses to stay in a storage room, forcing Pinback to chase it around the ship and eventually kill it with a gun. Pinback claims he is actually liquid fuel specialist Bill Frug, who inadvertently took the "real" Sergeant Pinback's place after he committed suicide by jumping into a fuel tank.

En route to their next target (the Veil Nebula), the Dark Star[ship Asterisk*] is hit by a bolt of electromagnetic energy during a storm, resulting in yet another on-board malfunction, with "Thermostellar Bomb #20" receiving an order to deploy. The ship's computer convinces Bomb #20 that the order was in error, and persuades the bomb to disarm itself and return to the bomb bay. Talby notes the malfunction, and investigates the fault. He discovers a damaged communications laser in the emergency airlock while the crew is engaging in their next bombing run. While Talby attempts to repair it, the laser malfunctions, blinding Talby and knocking him unconscious, causing extensive damage to the main computer, and damaging the bomb release mechanism on Bomb #20.

Due to the damage to the ship's computer, the crew members cannot activate the release mechanism and attempt to abort the drop. After two prior accidental deployments, Bomb #20 refuses to disarm or abort the countdown sequence. The computer activates dampers to confine the blast to a diameter of one mile, but that is all it can do at the moment. As Pinback and Boiler try to talk the bomb out of blowing up underneath the ship, Doolittle revives Commander Powell, who advises him to teach the bomb the rudiments of phenomenology. After donning a space suit and exiting the ship to approach the bomb directly, Doolittle engages in a philosophical conversation with Bomb #20 until it decides to abort its countdown and retreat to the bomb bay for further contemplation.

When attempting to assist Doolittle in re-entering the ship, Pinback inadvertently jettisons Talby out of the airlock. As Doolittle tries to rescue the now-conscious Talby, Pinback addresses the bomb over the intercom in another attempt to disarm it. Doolittle has mistakenly taught the bomb Cartesian doubt and, as a result, Bomb #20 determines that it can only trust itself and not external input. Convinced that only it exists, and that its sole purpose in life is to explode, Bomb #20 detonates. The Dark Star[ship Asterisk*] is destroyed, and Pinback and Boiler are killed instantly. Commander Powell is flung into space encased in ice, and Talby and Doolittle are blown in opposite trajectories. Talby drifts into the Phoenix Asteroids (a cluster he has long had a fascination with), destined to circumnavigate the universe for eternity. As Doolittle loses contact with Talby, he sees that he is falling toward the unstable planet. Realizing he will burn up upon entering its atmosphere, he drifts into debris from the Dark Star[ship Asterisk*], finds a surfboard-shaped hunk of debris, and "surfs" down into the atmosphere, dying as a falling star.>>

Re: APOD: Along the Western Veil (2019 Sep 19)

by starsurfer » Thu Sep 19, 2019 9:52 am

wolfie138 wrote: Thu Sep 19, 2019 6:14 am Looks like a crocodile.
Looks like a supernova remnant? :? :lol2:

Also a nice song for those that might not have heard it:
Click to play embedded YouTube video.

Re: APOD: Along the Western Veil (2019 Sep 19)

by TheOtherBruce » Thu Sep 19, 2019 9:31 am

Those figures are intriguing; 1500 light years away, and over 5000 years ago. Could there be a written (or chiselled) record somewhere, maybe one we know about but just don't understand yet?

Re: APOD: Along the Western Veil (2019 Sep 19)

by FLPhotoCatcher » Thu Sep 19, 2019 6:29 am

wolfie138 wrote: Thu Sep 19, 2019 6:14 am Looks like a crocodile.
To me, it looks more like the traditional depiction of the devil.

Re: APOD: Along the Western Veil (2019 Sep 19)

by wolfie138 » Thu Sep 19, 2019 6:14 am

Looks like a crocodile.

APOD: Along the Western Veil (2019 Sep 19)

by APOD Robot » Thu Sep 19, 2019 4:05 am

Image Along the Western Veil

Explanation: Delicate in appearance, these filaments of shocked, glowing gas, are draped across planet Earth's sky toward the constellation of Cygnus. They form the western part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star. Light from the original supernova explosion likely reached Earth over 5,000 years ago. Blasted out in the cataclysmic event, the interstellar shock wave plows through space sweeping up and exciting interstellar material. The glowing filaments are really more like long ripples in a sheet seen almost edge on, remarkably well separated into atomic hydrogen (red) and oxygen (blue-green) gas. Also known as the Cygnus Loop, the Veil Nebula now spans nearly 3 degrees or about 6 times the diameter of the full Moon. While that translates to over 70 light-years at its estimated distance of 1,500 light-years, this telescopic image of the western portion spans about half that distance. Brighter parts of the western Veil are recognized as separate nebulae, including The Witch's Broom (NGC 6960) along the top of this view and Pickering's Triangle (NGC 6979) below and left.

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