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

[APOD Robot]

Comet Lovejoy over The Great Wall

Explanation: Fading now as it returns to the outer solar system Comet Lovejoy (C/2013 R1) still graces planet Earth's sky, a delicate apparition in binoculars or small telescopes. The comet, a relic of the solar system's formative years, is seen here rising in the morning twilight on January 12 among the stars of Ophiuchus, the Serpent Bearer. Posing near the comet is bright star Alpha Ophiuchi, also known as Rasalhague, from Arabic "the head of the serpent collector". Of course, the serpentine shape below is the ancient Great Wall of China, along the Panlongshan section northeast of Beijing. Panlongshan is translated as "a coiled dragon". A moving and fortuitous scene, it was captured with a digital camera and telephoto lens in two consecutive exposures. The exposures were merged to show a natural looking foreground and twilight sky.

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[Beyond]

Is China on the right side, or the left side of the wall?

[Ann]

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).

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

[geckzilla]

Is China on the right side, or the left side of the wall?

Both. Historical borders have long since changed.
http://en.wikipedia.org/wiki/File:Map_o ... _China.jpg

[Nitpicker]

Is China on the right side, or the left side of the wall?

Both. Historical borders have long since changed.
http://en.wikipedia.org/wiki/File:Map_o ... _China.jpg

Yes, but since we are looking at the comet rise before dawn, we are looking eastward, so North is on the left. The wall was originally built to protect people to the South from people raiding from the North.

Lovely image. I wonder how often one sees a clear sky this close to Beijing these days?

[bystander]

Is China on the right side, or the left side of the wall?

Yes

[Nitpicker]

Is China on the right side, or the left side of the wall?

Yes

And outer space is discernable from the wall.

[geckzilla]

Yes, but since we are looking at the comet rise before dawn, we are looking eastward, so North is on the left. The wall was originally built to protect people to the South from people raiding from the North.

Lovely image. I wonder how often one sees a clear sky this close to Beijing these days?

Every now and then Pat attempts to school me on Chinese history. Constructing such an immense wall seems reasonable given what the Mongolian horde did to those who opposed them. Of course, there's a lot more history to it than that.

[Nitpicker]

Yes, but since we are looking at the comet rise before dawn, we are looking eastward, so North is on the left. The wall was originally built to protect people to the South from people raiding from the North.

Lovely image. I wonder how often one sees a clear sky this close to Beijing these days?

Every now and then Pat attempts to school me on Chinese history. Constructing such an immense wall seems reasonable given what the Mongolian horde did to those who opposed them. Of course, there's a lot more history to it than that.

I should probably have mentioned that what I know about the reasons for building the wall are based on what my primary school teachers told me.

[Boomer12k]

"Comet, Comet, way up high...Keep on going in the sky....uh huh... uh huh.... oh yeah...DO IT!!!!"

And that is my Comet CHEER!!!

What a great picture of the Great Wall, Snaking across the tops of ridges. Like a Dragon...

:---[===] *

[neufer]

[b][color=#0000FF][size=135]The Great Wall includes clusters Hercules, Coma and Leo on the right of this view of the local universe.[/size][/color][/b]

---

<<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.>>

[jsanchezjr]

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

[Beyond]

Is China on the right side, or the left side of the wall?

Yes

Tks.

[NGC3314]

The poor guy never saw a single comet althougt the purpose of the catalog was precisely that.

Wikipedia says Messier discovered 13 comets.

[neufer]

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

---

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.

<<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.>>

[neufer]

The poor guy never saw a single comet althougt the purpose of the catalog was precisely that.

Wikipedia says Messier discovered 13 comets.

[b][color=#0000FF]The tails of Comet Klinkenberg-Chéseaux, before sunrise on March 9, 1744[/color][/b]

---

<<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.>>

[jsanchezjr]

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.

[Ron-Astro Pharmacist]

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??

[Cousin Ricky]

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

[starsurfer]

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.

[Cousin Ricky]

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.

[Guest]

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!

[Beyond]

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

[Anthony Barreiro]

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?

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.

[Ann]

The barbarian side of the Wall. I like it.

And yes, that cluster should be NGC 6633.

Ann