APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

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Expand view Topic review: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Nitpicker » Fri Feb 21, 2014 3:20 am

rstevenson wrote:
Anthony Barreiro wrote:
rstevenson wrote: Nope, that's absolutely natural, since it may be the result of actions taken by humans, and humans seem to be native to this planet.
So how would you define "artificial"? Or are you saying the term has no meaning?
Artificial has a meaning of course, as Art(ifice) has pointed out. What I was suggesting is that we humans have a bad habit of abstracting ourselves from everything else, calling everything else natural, while what we do or cause to have done is, by implication, artificial. But what if the results of our joint actions cannot be predicted (by all but a few specialists) and perhaps not even appreciated after the fact by most people. Are we acting according to our nature or not? If we are, then the results of our actions are natural, not artificial.

If a herd of wild cattle overgrazes its land, is that natural? If we "overgraze" our environment, isn't that also natural? Is there any difference between the predations of a hyena and the "predations" of an energy glutton? It seems that there are many people, perhaps tens of millions, who abhor what we're doing to our environment, I among them. But there are billions more who are either unaware of the problem or who care little about it. In the aggregate, the actions of the human race are changing the environment, likely for the worse even in our own terms. But our actions are not unnatural. Alas, for if they were, we could probably devise a way to mend them.

Rob
Rob, I tend to agree with the thrust of your argument, including the fact that it is also partly a semantic argument over the various meanings of "natural" and "artificial".

We often (like to) think of humanity as a group, but it rarely exhibits group behaviour. For what it is worth, I really don't believe that humanity is capable of wiping itself out entirely, even though I think human activity is altering the climate. It will take a much bigger force of nature (artificial or otherwise) to get rid of all of us. Until then, civilizations will continue to rise and fall, and people will continue to prosper and perish. There will be much joy and much suffering, and a great deal of it will be due mainly to dumb luck. But if the "success" of humanity is measured only by how many of us exist at any one time, or how well we can maintain our ways of life, then I really do struggle to see the point. Does humanity even need to succeed? Do we just need parts of it to succeed? Who is handing out the prizes? [Hmmm, perhaps I need to get off the computer and talk to another real, live, human.]

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by rstevenson » Thu Feb 20, 2014 11:45 pm

Anthony Barreiro wrote:
rstevenson wrote:
Anthony Barreiro wrote: Does the absence of sea ice in the Arctic Ocean count as an artificial feature? :(
Nope, that's absolutely natural, since it may be the result of actions taken by humans, and humans seem to be native to this planet.
So how would you define "artificial"? Or are you saying the term has no meaning?
Artificial has a meaning of course, as Art(ifice) has pointed out. What I was suggesting is that we humans have a bad habit of abstracting ourselves from everything else, calling everything else natural, while what we do or cause to have done is, by implication, artificial. But what if the results of our joint actions cannot be predicted (by all but a few specialists) and perhaps not even appreciated after the fact by most people. Are we acting according to our nature or not? If we are, then the results of our actions are natural, not artificial.

If a herd of wild cattle overgrazes its land, is that natural? If we "overgraze" our environment, isn't that also natural? Is there any difference between the predations of a hyena and the "predations" of an energy glutton? It seems that there are many people, perhaps tens of millions, who abhor what we're doing to our environment, I among them. But there are billions more who are either unaware of the problem or who care little about it. In the aggregate, the actions of the human race are changing the environment, likely for the worse even in our own terms. But our actions are not unnatural. Alas, for if they were, we could probably devise a way to mend them.

Rob

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by jsanchezjr » Thu Feb 20, 2014 10:49 pm

starsurfer wrote:
jsanchezjr wrote: poor guy never saw a single comet althougt the purpose of the catalog was precisely that.

Wikipedia says Messier discovered 13 comets.


May be I was to much categorical, my bad. He was a comet hunter and logicaly he must see multiple of them.
Messier's catalogue was of things that were not a comet to help other astronomers if they happened to find those particular things and confuse them for comets.
Absolutely. He know what he was doing. Sorry, it was only a joke. And I don't was there but come on! He could have been wrong in some of them, don't you think? :)

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Beyond » Thu Feb 20, 2014 10:47 pm

Anthony Barreiro wrote:
neufer wrote:1. Made or contrived by Art.
Thanks Art, but I was asking Rob.
Art's just trying to China stone wall us. :lol2:

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by neufer » Thu Feb 20, 2014 10:47 pm

Anthony Barreiro wrote:
neufer wrote:
1. Made or contrived by Art.
Thanks Art, but I was asking Rob.
  • 2. :cry:

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Anthony Barreiro » Thu Feb 20, 2014 10:33 pm

neufer wrote:1. Made or contrived by Art.
Thanks Art, but I was asking Rob.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by neufer » Thu Feb 20, 2014 10:29 pm

rstevenson wrote:
Anthony Barreiro wrote:
Does the absence of sea ice in the Arctic Ocean count as an Artificial feature? :(
Nope, that's absolutely natural, since it may be the result of actions taken by humans, and humans seem to be native to this planet.
Artificial, a. [L. Artificialis, fr. Artificium: cf. F. Artificiel. See Artifice.]
  • 1. Made or contrived by Art.

    Artificial strife Lives in these touches, livelier than life. Shak.

    2. Feigned; fictitious; assumed; affected; not genuine.

    Artificial tears. Shak.

    3. Artful; cunning; Crafty. [Obs.] Shak.

    4. Cultivated; not indigenous; not of spontaneous growth; as, Artificial grasses.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Anthony Barreiro » Thu Feb 20, 2014 10:07 pm

rstevenson wrote:
Anthony Barreiro wrote:
Ann wrote:I'll let somebody else answer Beyond's question and instead ponder the fact that Comet Lovejoy is apparently looking down on the only artificial feature on the Earth that is visible from space, except it isn't visible from space (at least not from the Moon and certainly not from the position of Comet Lovejoy).
Does the absence of sea ice in the Arctic Ocean count as an artificial feature? :(
Nope, that's absolutely natural, since it may be the result of actions taken by humans, and humans seem to be native to this planet.

Rob
So how would you define "artificial"? Or are you saying the term has no meaning?

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by rstevenson » Thu Feb 20, 2014 9:31 pm

Anthony Barreiro wrote:
Ann wrote:I'll let somebody else answer Beyond's question and instead ponder the fact that Comet Lovejoy is apparently looking down on the only artificial feature on the Earth that is visible from space, except it isn't visible from space (at least not from the Moon and certainly not from the position of Comet Lovejoy).
Does the absence of sea ice in the Arctic Ocean count as an artificial feature? :(
Nope, that's absolutely natural, since it may be the result of actions taken by humans, and humans seem to be native to this planet.

Rob

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by neufer » Thu Feb 20, 2014 9:28 pm


Ann wrote:
I'll let somebody else answer Beyond's question and instead ponder the fact that Comet Lovejoy is apparently looking down on the only artificial feature on the Earth that is visible from space, except it isn't visible from space (at least not from the Moon and certainly not from the position of Comet Lovejoy).
http://earthobservatory.nasa.gov/IOTD/view.php?id=1455 wrote:
:arrow: <<This Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sub-image covers a 12 x 12 km area in Northern Shanxi Province, China, and was acquired January 9, 2001. The low sun angle, and light snow cover highlight a section of the Great Wall, visible as a black line running diagonally through the image from lower left to upper right. The Great Wall is more than 2000 years old and was built over a period of 1000 years. Stretching 4500 miles from Korea to the Gobi Desert, it was first built to protect China from marauders from the north.

Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS,
and U.S./Japan ASTER Science Team.
Anthony Barreiro wrote:
Does the absence of sea ice in the Arctic Ocean count as an artificial feature? :(
Sure... among other things:

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Ann » Thu Feb 20, 2014 9:22 pm

The barbarian side of the Wall. I like it.

And yes, that cluster should be NGC 6633.

Ann

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Anthony Barreiro » Thu Feb 20, 2014 8:41 pm

Ann wrote:I'll let somebody else answer Beyond's question and instead ponder the fact that Comet Lovejoy is apparently looking down on the only artificial feature on the Earth that is visible from space, except it isn't visible from space (at least not from the Moon and certainly not from the position of Comet Lovejoy).
Does the absence of sea ice in the Arctic Ocean count as an artificial feature? :(
Ann wrote:The nice open cluster in the picture is IC 4665. Do check out Capella Observatory and go to Images and Open Clusters to see IC 4665. Don't miss the Double cluster while you are there!

Nice APOD.

Ann
It is a beautiful apod. I love the sinuous shapes of the Great Wall and the hills and Serpens. IC 4665 jumped out at me, too. I believe the more compact cluster northeast from IC 4665 (directly below the comet and above the gap in the hills on the barbarian side of the Wall) is NGC 6633.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Beyond » Thu Feb 20, 2014 8:38 pm

Just sorta short and to the point. We older people don't have time to mess around. :mrgreen:

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Guest » Thu Feb 20, 2014 6:41 pm

Beyond wrote:
bystander wrote:
Beyond wrote:Is China on the right side, or the left side of the wall?
Yes
Tks.

hehe - I like this kind of dry and efficient exchange! :mrgreen:

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Cousin Ricky » Thu Feb 20, 2014 6:20 pm

Ann wrote:I'll let somebody else answer Beyond's question and instead ponder the fact that Comet Lovejoy is apparently looking down on the only artificial feature on the Earth that is visible from space, except it isn't visible from space (at least not from the Moon and certainly not from the position of Comet Lovejoy).
This was speculated decades before anyone went into outer space to see for themselves. There are plenty of artificial features that can be seen from farther out than the wall is visible.

Here is a satellite photo of a section of the Great Wall. See how far you can zoom out before you can no longer see it. I suspect our eyes can pick out linear features that wouldn’t be preserved in a digital image, but you still get the idea from this exercise. Now, keep zooming out until you see a giant gray splotch to the south. That is Beijing, certainly more outstanding than the Wall.

It’s easy to come up with other examples, looking no further than my life experience. Compare the Wall to artificial land near my birthplace and near where I went to college. Also compare it to a beautiful artificial structure in a country which, regretably, I will never visit because I would be eligible for the death penalty for just being there.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by starsurfer » Thu Feb 20, 2014 6:08 pm

jsanchezjr wrote:
NGC3314 wrote:
jsanchezjr wrote:The poor guy never saw a single comet althougt the purpose of the catalog was precisely that.
Wikipedia says Messier discovered 13 comets.

May be I was to much categorical, my bad. He was a comet hunter and logicaly he must see multiple of them.
Messier's catalogue was of things that were not a comet to help other astronomers if they happened to find those particular things and confuse them for comets.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Cousin Ricky » Thu Feb 20, 2014 5:27 pm

Is that a satellite streak underneath sigma Ophiuchi and off to the right edge?

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Ron-Astro Pharmacist » Thu Feb 20, 2014 4:16 pm

Looking at this makes one want to explore the multiple dimensions – up into the sky, along the length of the wall, over the mountains into the sunrise or out into the cosmos with the comet. Great photo. Poster material – where do you sign up??

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by jsanchezjr » Thu Feb 20, 2014 2:45 pm

NGC3314 wrote:
jsanchezjr wrote:The poor guy never saw a single comet althougt the purpose of the catalog was precisely that.
Wikipedia says Messier discovered 13 comets.

May be I was to much categorical, my bad. He was a comet hunter and logicaly he must see multiple of them.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by neufer » Thu Feb 20, 2014 2:01 pm

NGC3314 wrote:
jsanchezjr wrote:
The poor guy never saw a single comet althougt the purpose of the catalog was precisely that.
Wikipedia says Messier discovered 13 comets.
http://en.wikipedia.org/wiki/C/1743_X1 wrote: <<Charles Messier (26 June 1730 – 12 April 1817) [first took an] interest in astronomy by the appearance of the spectacular, great six-tailed comet in 1744 and by an annular solar eclipse visible from his hometown on 25 July 1748.

The Great Comet of 1744, also known as Comet Klinkenberg-Chéseaux, was a spectacular comet that was observed during 1743 and 1744. It became visible with the naked eye for several months in 1744 and displayed dramatic and unusual effects in the sky. Its absolute magnitude — or intrinsic brightness — of 0.5 was the sixth highest in recorded history. By February 18, 1744, it reportedly was as bright as the planet Venus (with an apparent magnitude of -4.6) and at this time displayed a double tail.

The comet reached perihelion about March 1, 1744, when it was 0.2 astronomical units from the sun. At about this time it was bright enough to be observed in daylight with the naked eye. As it moved away from perihelion, a spectacular tail developed — extending well above the horizon while the comet's head remained invisible due to the morning twilight. In early March 1744, Chéseaux and several other observers reported an extremely unusual phenomenon — a 'fan' of six separate tails rose above the horizon. It has been suggested that the 'fan' of tails was generated by as many as three active sources on the cometary nucleus, exposed in turn to solar radiation as the nucleus rotated. It also has been proposed that the tail phenomenon was a very prominent example of the "dust striae" seen in the tails of some comets, such as Comet West and C/2006 P1 (McNaught).

The Great Comet of 1744 also was noted in Chinese astronomical records. Researchers have found that some of their observations describe audible sounds associated with the comet, which may, if true, have resulted from the interaction of particles with the Earth's magnetosphere, as sometimes described for the aurora.>>

I am Temujin...Barbarian...

by neufer » Thu Feb 20, 2014 1:44 pm

geckzilla wrote:
Constructing such an immense wall seems reasonable given what the Mongolian horde did to those who opposed them.

Webster's Revised Unabridged Dictionary (1828) wrote:
Horde, n. [F. horde (cf. G. horde), fr. Turk. ord, ordī, camp; of Tartar origin.]
  • A company of wandering people dwelling in tents or wagons, and migrating from place to place to procure pasturage for their cattle. Such are some tribes of the Tartars in the north of Asia. A hord usually consists of fifty or sixty tents.
http://en.wikipedia.org/wiki/The_Conqueror_%28film%29 wrote:
<<The Conqueror is a 1956 CinemaScope epic film produced by Howard Hughes and starring John Wayne as the Mongol conqueror Genghis Khan. Other performers included Susan Hayward, Agnes Moorehead, and Pedro Armendáriz. Directed by actor/director Dick Powell, the film was principally shot near St. George, Utah 220 km downwind of the Nevada's extensive (1953) above-ground nuclear weapons testing site. Wayne, who was at the height of his career, had lobbied for the Genghis Khan role after seeing the script but he was widely believed to have been grossly miscast (he was "honored" by The Golden Turkey Awards). Years later, The Conqueror was included in the book The Fifty Worst Films of All Time. Reportedly, Howard Hughes felt guilty about his decisions regarding the film's production, particularly over the decision to film at a hazardous site. He bought every print of the film for $12 million and kept it from view until 1974 when it was first broadcast on TV. The Conqueror, along with Ice Station Zebra, is said to be one of the films Hughes watched endlessly during his last years.>>

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by NGC3314 » Thu Feb 20, 2014 1:41 pm

jsanchezjr wrote:The poor guy never saw a single comet althougt the purpose of the catalog was precisely that.
Wikipedia says Messier discovered 13 comets.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by Beyond » Thu Feb 20, 2014 1:40 pm

bystander wrote:
Beyond wrote:Is China on the right side, or the left side of the wall?
Yes
Tks.

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by jsanchezjr » Thu Feb 20, 2014 1:36 pm

Messier had been very happy of seeing the Lovejoy comet. Yesterday I was in a conference about supernovas(very, super very interesting) and talk about the messier catalog. The poor guy never saw a single comet althougt the purpose of the catalog was precisely that. You can image Messier looking to the sky trying finding something moving and talking like: "Well, let see what I can find.... Ok there is something, let call it M1. Day 1 and doesn't move, day 2 and doesn't move, Day 15 and doesn't move....Hmmmm definitely that is not a comet.
Ok that other looks like a comet, let it call it M2. Day 1 and doesn't move, day 2 and doesn't move, Day 15 and doesn't move....Dam! that is not a comet too". In that way he could catalog more than a hundred celestial object like galaxies, super novas, planetary nebula etc. Astronomy is weird

Re: APOD: Comet Lovejoy over The Great Wall (2014 Feb 20)

by neufer » Thu Feb 20, 2014 1:27 pm

http://en.wikipedia.org/wiki/CfA2_Great_Wall wrote: <<The Great Wall (also called Coma Wall), sometimes specifically referred to as the CfA2 Great Wall, is one of the largest known superstructures in the Universe, (the largest being the Hercules–Corona Borealis Great Wall). It is a filament of galaxies approximately 200 million light-years away and has dimensions which measure over 500 million light-years long, 300 million light-years wide and 16 million light-years thick, and includes the Hercules Supercluster, the Coma Supercluster and the Leo Cluster. It was discovered in 1989 by Margaret Geller and John Huchra based on redshift survey data from the CfA Redshift Survey. It is not known how much farther the wall extends due to the plane of the Milky Way galaxy in which Earth is located. The gas and dust from the Milky Way (known as the Zone of Avoidance) obscure the view of astronomers and have so far made it impossible to determine if the wall ends or continues on further than they can currently observe.

In the standard model of the evolution of the universe, such structures as the Great Wall form along and follow web-like strings of dark matter. It is thought that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts baryonic matter, and it is this "normal" matter that astronomers see forming long, thin walls of super-galactic clusters.>>

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