APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 28)

Comments and questions about the APOD on the main view screen.
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Re: First Visit?

Post by neufer » Mon Oct 28, 2013 8:01 pm

Chris Peterson wrote:
Spif wrote:
So what I'm wondering is, what are the odds? Whatever nudged this comet initially must have been pretty severe to divert it from a presumably stable orbit way out there and subsequently aim it almost directly at the sun? That must have been a huge deflection.
Not sure what you mean by "what are the odds". There may be billions of bodies in the Oort cloud, so the chance that any one of them will be perturbed into the inner system is small. But such perturbations are common, happening every few years. So in that sense, the odds are high.

Bodies that distance from the Sun are bound only very lightly. While their orbits may be seen as stable, they need only the slightest perturbation- just a few meters per second- to reach escape velocity. Nothing more than a close pass from another small body, a chance positioning of the planets, or even the position of a nearby star can be enough to generate the necessary delta-v. So these bodies are very easily deflected into highly eccentric orbits that pass close to the Sun. It isn't a large deflection at all.
While it takes only a small deflection to nullify an Oort cloud object's angular momentum...
how does the angular momentum get canceled out almost completely :?:

This will be the first pass of Comet ISON (C/2012 S1) and it has an eccentricity ~ 1.0000021.

You've got to figure that the chance of changing from a small quasi-circular Oort cloud eccentricity of 0.3 ± 0.3
to a quasi-parabolic sungrazer eccentricity of 1.0 ± 0.0000021 must be about 1 in 100,000.

(Where's Ernst Mach when you need him?)
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Re: First Visit?

Post by Chris Peterson » Mon Oct 28, 2013 8:16 pm

neufer wrote:While it takes only a small deflection to nullify an Oort cloud object's angular momentum...
how does the angular momentum get canceled out almost completely?
How are you figuring that the (orbital) angular momentum of the comet has changed significantly?
This will be the first pass of Comet ISON (C/2012 S1) and it has an eccentricity ~ 1.0000021.
To be clear, it is likely this body remains in a closed solar orbit.
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by ta152h0 » Mon Oct 28, 2013 10:24 pm

I am not a person who was given the appreciation of art as my mother ( RIP ) tried so hard to do so I always question how art and science can benefit each other. Science to art is easy but the reverse may be questionable. This APOD makes the latter more plausible.
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by geckzilla » Mon Oct 28, 2013 11:25 pm

That would depend on how broad your definition of art is, Wolf. Skill in many types of art I would say are indispensable to science. You need to be able to communicate ideas so writing and verbal skills are essential. Illustration helps a lot. And, of course, innovations in science would probably be very slow without creativity and imagination. If you are strictly referring to paintings and statues of crusty old gods and myths then yeah, those aren't very useful unless you are a historian or anthropologist.
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by John McPhee » Tue Oct 29, 2013 12:16 am

I thought the comet would be brightest, if it survives its encounter with the sun, in late December, not the end of November?

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by L. McNish » Tue Oct 29, 2013 2:35 am

I'm pretty sure Anthony Barreiro got it right. Given the angle the comet's tail makes with the horizon, I'd say it's a view to the west-southwest after sunset on approximately Christmas Eve 1680 (Gregorian calendar). The only time the Moon was to the "left" of the 1680 comet was after perihelion, and if it was just out of frame to the top left, this would account for the lighting and various shadow angles on the ground. The bright stars in the painting however, do not seem to agree with my simulation so I would suggest these were added later against the red sky. Both Venus and Mercury would also have been visible rising on the left from the horizon up towards the Moon, but these are also missing from the painting (also perhaps out of frame).

A very interesting picture by an artist of scientists performing real science outdoors at a special time of year with two churches to guide us to the date, time and location.

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Stinky Old Man » Tue Oct 29, 2013 4:10 pm

ta152h0 wrote:I am not a person who was given the appreciation of art as my mother ( RIP ) tried so hard to do so I always question how art and science can benefit each other. Science to art is easy but the reverse may be questionable. This APOD makes the latter more plausible.
Earth without art is literally just "eh"

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by neufer » Tue Oct 29, 2013 4:38 pm

http://en.wikipedia.org/wiki/Eusebio_Francisco_Kino wrote:
<<Eusebio Francisco Kino, (10 August 1645 – 15 March 1711) was a Jesuit priest whose Exposisión astronómica de el cometa (Mexico City, 1681) on the Great Comet of 1680 is among the earliest scientific treatises published by a European in the New World. This publication was later the subject of a sonnet by the noted colonial nun and poetess of New Spain, Sor (Sister) Juana Inés de la Cruz.

Kino's was the son of Franz Kühn (or Francesco Chini) and he was educated in Innsbruck, Austria. He taught mathematics in Ingolstadt, he received Holy Orders as a priest on 12 June 1677. Although Kino wanted to go to the Orient, he was sent to New Spain. Due to travel delays while crossing Europe, he missed the ship on which he was to travel and had to wait a year for another ship. While waiting in Cadiz, Spain, he wrote some observations, done during late 1680 and early 1681, about his study of a comet (later known as Kirch's comet), which he subsequently published upon arriving in Mexico.

Father Kino enjoyed making model ships out of wood. His knowledge of maps and ships led him to believe that Mexican Indians could easily access Baja California by sea, a view taken with skepticism by missionaries in Mexico City. When Kino proposed and began making a boat that would be pushed across the Sonoran Desert to the Mexican west coast, a controversy arose, as many of his co-missionaries began to question Kino's faculties. However, Kino was able to prove that Baja California is not an island by leading an overland expedition there.

Kino opposed the slavery and compulsory hard labor in the silver mines that the Spaniards forced on the native people. In 1965, a statue of Kino was donated to the United States Capitol's National Statuary Hall collection, one of two statues representing Arizona. In John Steinbeck's novel, The Pearl, it is implied the protagonist is named after the missionary.>>
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by geckzilla » Tue Oct 29, 2013 6:02 pm

Stinky Old Man wrote:
ta152h0 wrote:I am not a person who was given the appreciation of art as my mother ( RIP ) tried so hard to do so I always question how art and science can benefit each other. Science to art is easy but the reverse may be questionable. This APOD makes the latter more plausible.
Earth without art is literally just "eh"
The puppeteer has created yet another sock puppet.
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Nitpicker » Tue Oct 29, 2013 11:32 pm

I think the painting depicts a WSW aspect (as I stated earlier), looking down the canal currently known as Steigersgracht, from a location near to where Rotterdam Blaak station is now. It is possible that this canal extended further eastwards in 1680, and it must have connected to the main river at that time too, so that the boats in the painting had somewhere to go.

I think the photo posted by BMAONE23 is nearby, but looking SSE down the canal currently known as Delftsavaart. Definitely the same church though.

It is also possible that Verschuier was not quite where the painting suggests he was. He might have painted the church in afterwards, to make the painting more Rotterdam-esque. If I were to put my art-critic hat on momentarily (no neufer, not my Art-critic hat), I would say that Verschuier was probably not considered to be one of the Dutch masters. His paintings must have more historical than artistic value. I am not game to take a punt on the exact date this painting is depicting, either, as the locations of stars and planets appear to be more abstract than figurative.

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Nitpicker » Wed Oct 30, 2013 4:35 am

The 1865 map of Rotterdam in this link (rotated CW a little from North):

http://www.flickr.com/photos/8725928@N0 ... 025753640/

shows a much more extensive canal network than exists today. There did indeed appear to be a waterway (named "Kola" if I read it correctly) around where Rotterdam Blaak railway station stands today.

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by neufer » Wed Oct 30, 2013 4:45 am

Anthony Barreiro wrote:
If we're looking southwest during evening dusk on Saturday 28 December, 1680, the light of the Moon, approaching first quarter, would account for the shadows on the snow-covered ground. The comet is conjuncting Venus! (This conjunction might account for the popularity of cross-staffs). The stars don't match up very well, but maybe Verschuier just put some random stars in for effect. According to his wikipedia article he was known for painting ships and landscapes, maybe he just wasn't very careful about creating a star chart.
  • The cross-staffs might make more sense if it was 'Eerste Kerstdag' the 25th of December.
http://www.jwwerner.com/history/Comet.html wrote: This is what the first Dutch settlers of Esopus, New York, saw in the sky over 300 years ago! Excerpt from The History of Kingston, by Marius Schoonmaker, 1888, at page 70:

On the 9th of December 1680, there appeared an extraordinary comet, which caused very great consternation throughout the province, with forebodings of dreadful happenings and divine punishments. It is described, in a letter dated January 1st, 1681, as having "appeared in the Southwest on the ninth of December last, about two o'clock in the afternoon, fair sunshine weather, a little above the sun, which takes its course more northerly, and was seen the Sunday night [Dec. 15, NS], right after about twilight, with a very fiery tail or streamer in the west, to the great astonishment of all spectators, and is now seen every night with clear weather. Undoubtedly, God threatens us with dreadful punishments if we do not repent." The letter then suggested the propriety of proclaiming a day of humiliation and prayer.
...........................................................................
One more “first hand” account of the Comet as seen from Scotland! Attributed to The Reverend Robert Law(approx 1624-1689). Law was a minister during the tumultuous “Restoration Period” of Scottish history and author of The Memorable Things that Fell Out within this Island of Brittain from 1638 to 1684.): ‘December 10 [Dec. 20, NS], being Fryday, 1680, after sun-sett, there appeared in the west a comet, having a large broad and great streamer coming from it, the lyke was never seen or read of, and continued till the 16th or 17th day of January, growing smaller and smaller to it’s end;
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by geckzilla » Wed Oct 30, 2013 4:50 am

I'm glad I live in the 2000's instead of the 1600's, but still... to be able to see comets over a city. For all that we've gained, we've still lost a little.
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Nitpicker » Wed Oct 30, 2013 5:03 am

geckzilla wrote:I'm glad I live in the 2000's instead of the 1600's, but still... to be able to see comets over a city. For all that we've gained, we've still lost a little.
Aye, how we've gained since the Late Heavy Bombardment:
http://en.wikipedia.org/wiki/Late_Heavy_Bombardment

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Ann » Wed Oct 30, 2013 6:07 am

Nitpicker wrote: Aye, how we've gained since the Late Heavy Bombardment:
http://en.wikipedia.org/wiki/Late_Heavy_Bombardment
Aye, but imagine being alive (however briefly) at that time and see spectacular comets and asteroids painting fantastic light tracks in the sky!!! :shock: :shock: :shock:

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Nitpicker » Wed Oct 30, 2013 7:18 am

Ann wrote:Aye, but imagine being alive (however briefly) at that time and see spectacular comets and asteroids painting fantastic light tracks in the sky!!! :shock: :shock: :shock:
Nay, I'd rather imagine an imaginary event horizon. :fish:
http://asterisk.apod.com/viewtopic.php?f=8&t=31680

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by neufer » Wed Oct 30, 2013 11:40 am

Click to play embedded YouTube video.
Ann wrote:
Aye, but imagine being alive (however briefly) at that time and see spectacular comets and asteroids painting fantastic light tracks in the sky!!! :shock: :shock: :shock:
Aye, those were the good old days:
  • 1681: The last dodo bird is killed.

    1681: July 1 – Oliver Plunkett, Roman Catholic Primate
    of Ireland, falsely convicted of treason, is hanged,
    drawn and quartered at Tyburn, London.

    1681: October 28 – A London woman is publicly flogged
    for the crime of "involving herself in politics."
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by ta152h0 » Wed Oct 30, 2013 4:08 pm

hmmm 1681 wasn't that great. !908 wasn't all that good in Tunguska either.
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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Nitpicker » Thu Oct 31, 2013 2:24 am

neufer wrote:1681: October 28 – A London woman is publicly flogged for the crime of "involving herself in politics."
They should have flogged all the similarly involved men, too. So many missed opportunities.

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Re: APOD: The Great Comet of 1680 Over Rotterdam (2013 Oct 2

Post by Beyond » Thu Oct 31, 2013 2:47 am

Probably just a shortage of floggers. Good help was probably as hard to get back then also. :yes:
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Re: First Visit?

Post by neufer » Fri Nov 01, 2013 6:03 pm

Chris Peterson wrote:
neufer wrote:
While it takes only a small deflection to nullify an Oort cloud object's angular momentum...
how does the angular momentum get canceled out almost completely?
How are you figuring that the (orbital) angular momentum of the comet has changed significantly?
My figuring was wrong on that matter but it has taken me this long to figure it all out.

At the Oort cloud distance of 50,000 AU the escape velocity ~188m/s
and the circular orbital velocity ~133m/s.

The (phase space) 3D Oort cloud velocity distribution at 50,000 AU basically fills a sphere of radius 133m/s with a 8.6m/s wide cylindrical axial hole down the center depleted due to interactions with the solar system at perihelion (= ~32AU at 4.3m/s radius). :arrow:

However, for Comet ISON to reach a perihelion as close as 0.01244AU it must have started within only about 8.6 centimeters per second of the center of that 8.6m/s wide cylindrical axial hole.

While this narrow cylinder represents only about 6 x 10-7 of the volume of the entire Oort cloud phase space a velocity change of 5 to 10 m/s at ~50,000AU is really all that would have been required.

Presumably this (5 to 10 m/s) perturbation was provided by a well positioned
passing red dwarf about 2 million years (= 0.5*(25,000)3/2) ago.

(Note: Alpha Centauri is currently in the process of inducing a ~1 m/s velocity perturbation on the Oort cloud but it is inducing a similar ~1 m/s velocity perturbation upon the whole solar system. Hence, the effective [quadrupole] Oort cloud perturbation [vis-a-vis the solar system] amounts to only about a ~0.1 m/s velocity perturbation.)
Chris Peterson wrote:
neufer wrote:
This will be the first pass of Comet ISON (C/2012 S1) and it has an eccentricity ~ 1.0000021.
To be clear, it is likely this body remains in a closed solar orbit.
Your figuring is wrong on that matter.

An Oort comet which starts at an aphelion of ~50,000AU needs very little extra energy to escape the solar system.

At perihelion Comet ISON will be traveling ~377 km/s or ~2,000 V where V = ~188 m/s (the escape velocity at 50,000AU).

If Comet ISON's velocity at perihelion could be slightly increased to just (2,000 + ϵ)V [where ϵ = 1/4,000]
then Comet ISON would have gained enough energy to reach escape velocity.

Hence, a perihelion velocity increase of just 47 millimeters per second (= 188 m/s/4000)
is all that is required to reach escape velocity :!:

In the case of a sungrazer this tiny (47mm/s) perihelion velocity increase could come either from:

  • 1) strong cometary (tail) jets near perihelion from a rotating cometary nucleus and/or

    2) a gravitational assist near perihelion from a Sun moving at ~13m/s in the anti-Jupiter direction.
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Re: First Visit?

Post by Chris Peterson » Fri Nov 01, 2013 6:24 pm

neufer wrote:
Chris Peterson wrote:To be clear, it is likely this body remains in a closed solar orbit.
Your figuring is wrong on that matter.
I didn't do any figuring. I'm simply noting that only a few percent of comets with osculating eccentricities greater than 1 as they neared perihelion actually were in hyperbolic solar escape orbits. The odds are that this one will also be elliptical once it is well pass perihelion.

The effects you mention can add energy to the orbit, but they can also remove it. In addition, there are other effects such as Yarkovsky that can be significant (either adding or removing energy, depending on the direction the body is rotating).

The bottom line is we won't know if this body is in an escape orbit until months after perihelion, but the odds are against it.
Chris

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Re: First Visit?

Post by Anthony Barreiro » Fri Nov 01, 2013 7:12 pm

Chris Peterson wrote:
neufer wrote:
Chris Peterson wrote:To be clear, it is likely this body remains in a closed solar orbit.
Your figuring is wrong on that matter.
I didn't do any figuring. I'm simply noting that only a few percent of comets with osculating eccentricities greater than 1 as they neared perihelion actually were in hyperbolic solar escape orbits. The odds are that this one will also be elliptical once it is well pass perihelion.

The effects you mention can add energy to the orbit, but they can also remove it. In addition, there are other effects such as Yarkovsky that can be significant (either adding or removing energy, depending on the direction the body is rotating).

The bottom line is we won't know if this body is in an escape orbit until months after perihelion, but the odds are against it.
I don't understand all the physics and math, but it seems to me that if this comet largely disintegrates around perihelion, it is unlikely to complete another orbit of any period or eccentricity. All that may be left would be dust, and maybe a nice meteor shower.
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Re: First Visit?

Post by neufer » Fri Nov 01, 2013 7:14 pm

Chris Peterson wrote:
neufer wrote:
A perihelion velocity increase of just 47 millimeters per second
is all that is required [for Comet ISON] to reach escape velocity :!:

In the case of a sungrazer this tiny (47mm/s) perihelion velocity increase could come either from:

  • 1) strong cometary (tail) jets near perihelion from a rotating cometary nucleus and/or

    2) a gravitational assist near perihelion from a Sun moving at ~13m/s in the anti-Jupiter direction.
The effects you mention can add energy to the orbit, but they can also remove it.
Since Comet ISON has a positive inclination and is approaching the Sun from the back side (vis-s-vis the Sun's ~13m/s orbit)
I'm pretty confident that (at least) the gravitational assist would add to the energy.
Chris Peterson wrote:
In addition, there are other effects such as Yarkovsky that can be significant (either adding or removing energy, depending on the direction the body is rotating).
The Yarkovsky effect is a photon type rocket whose momentum contribution is quite weak due to the E/c relationship. That's O.K. for long term effects on meteoroids and small asteroids but not for short term effects on comets. The chemical rocket equivalent of cometary jets should be much more efficient (solar energy wise) in generating thrust.

Still, I'm guessing that the solar gravitational assist dominates.
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Re: First Visit?

Post by Chris Peterson » Fri Nov 01, 2013 8:17 pm

neufer wrote:The Yarkovsky effect is a photon type rocket whose momentum contribution is quite weak due to the E/c relationship. That's O.K. for long term effects on meteoroids and small asteroids but not for short term effects on comets. The chemical rocket equivalent of cometary jets should be much more efficient (solar energy wise) in generating thrust.
The Yarkovsky effect can be significant for bodies passing very near the Sun, even in the short term.

The material that is ejected from comets typically doesn't alter the cometary orbit. In fact, I'm not aware of any case of that type of perturbation being observed.

What happens as the nucleus passes the Sun remains to be seen. Again, though, the statistics suggest this comet is not in an escape orbit.
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