Note: See updates below for the ISON ISOFF ISON nature of this comet that has everybody guessing. Picture at right also updated to reflect the new “zombie” status of this comet.
Looks like ISON has disintegrated during its turn around the sun. Given the radiation (estimated temperature 5,000F/2,760C – hot enough to vaporize rock), solar wind, and the tidal-forces (even though smallish, thanks Gavin) associated with its proximity and nearly 800,000 mph speed around the turn about that time, I’m not surprised. Watch the second video below where it goes “poof” (h/t to reader “David”)
NASA’s spaceweather.com reports:
Comet ISON is making its closest approach to the sun, and evidence is mounting that the nucleus of the comet has disintegrated. Watch the head of the comet fade dramatically as it approaches the sun in this SOHO coronagraph movie:
(may take a minute to load)
![sundiver_anim3[1]](http://wattsupwiththat.files.wordpress.com/2013/11/sundiver_anim31.gif)
The movie spans a day and a half period from Nov. 27th (01:41 UT) to 28th (15:22 UT). In the early hours of the 27th, Comet ISON brightens dramatically, saturating the pixels in the digital camera of the SOHO’s coronagraph. By mid-day on the 28th, however, the comet’s head appears to fade. This is a sign that the nucleus has likely fallen apart. That would make ISON a headless comet–more appropriate for Halloween than Thanksgiving.
Researchers working with the Solar Dynamics Observatory report that they are seeing nothing along the track that ISON was expected to follow through the sun’s atmosphere.
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UPDATE: Watch it go “poof” here:
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UPDATE2: NASA JPL Insider Amy Mainzer tweets some last minute hope that ISON may be “undead”
http://twitter.com/AmyMainzer/status/406179229487742976
A zombie comet, how cool is that?
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UPDATE3: Now it seems back again, but looking entirely different than before. A number of astronomers indicate they don’t know what is left of it, maybe a chunk, maybe a smooshed drawn out nucleus or something else. Image from SOHO’s coronagraph:
sheeesh Dr. S.
“Your Momma don’t Dance.” Loggins and Messina
The next solar cycle 25 is going to be smaller than 24. We don’t even know what the effects of an even smaller heliosphere might bring. How many gravitational constants aren’t so constant.
There are consequences to/ from flux uations.
And the sun eats comets..chomp..chomp..another form of ‘A’ccretion. (the A word but again)
Apparently lots of them based on observations..
Carla says:
November 30, 2013 at 9:31 am
The next solar cycle 25 is going to be smaller than 24. We don’t even know what the effects of an even smaller heliosphere might bring.
sheeesh Carla. Comets don’t care about the heliosphere.
That the sun accretes more matter during minimum periods (focusing) and less during high activity periods, (de-focusing) well.
that is it for todays rant.
Off to morph in the Oort cloud to find some gravitational constants..lol
Carla says:
November 30, 2013 at 9:39 am
That the sun accretes more matter during minimum periods (focusing) and less during high activity periods, (de-focusing) well.
Is not relevant for comets coming and going.
that is it for todays rant.
perhaps a little less ranting would be welcome.
Leif,
The distance within which tidal breakup occurs is called the Roche-limit. Wikipedia has a good article on that http://en.wikipedia.org/wiki/Roche_limit but the table for selected examples is wrong [the unit should be km not meter]. Anyway, you can see that ISON is outside the Roche limit.
I assume that ISON was within the Roche limit at perihelion. For an average comet near the sun, a Roche-limit of 1,234,000 km is mentioned (for rigid bodies, see the website of wikipedia) while at perihelion, the comet was only 1,166,000 km above the solar surface. But it is unclear for me if with the formula “d = 1.26 R_M (…)” the Roche-limit ‘d’ starts from the center of the Sun or from the surface.
This webpage http://www.asterism.org/tutorials/tut25-1.htm is more clear, where ‘L_R’ (Roche-limit) starts obviously from the center. It is stated: “The Sun’s limit for comets is 2.4 million km”, i.e. from the center. At perihelion, the comet ISON was only 1,862,000 km away from the solar center.
You’re still not grasping the what I’m trying to tell you. Listen up, I’m trying to teach you something.
It doesn’t help to try to think of ordinary 3-D Euclidian space as “curved”. Einstein conceived that concept thinking in 4-dimensional Riemannian manifolds, where the 4th dimension is time.
It’s also not helpful to say that curved space should be used instead of forces. Or that Newtonian physics is wrong and should be replaced by “relativity”.
A better way to view this is to understand that in the General Relativity framework, forces are not needed to understand free-falling objects, because the theory integrates gravity into the concept of distance measuring (metric tensor) such that free-falling objects (such as nearly-destroyed comets orbiting away from the Sun) are merely taking the shortest possible distance from point A to point B, along geodesics, which _might_ look curved to us.
Or not. The other important concept of General Relativity is that it doesn’t destroy Newtonian Physics, but _preserves_ it as the limiting cases for spaces with weak gravity (“flat space”) or low speeds (non-relativistic). So if you’re not near some big chunk of mass or approaching the speed of light, Newtonian physics still works fine.
Newtonian physics got 12 astronauts to the Moon and back safely, so you really shouldn’t worry much about the anomaly in the precessing rate of Mercury’s perihelion which you said is fixed by relativity. The total error rate in that anomaly amounts to 43 arc-seconds per century. Big whoop. This anomaly is barely measurable in the other planets. Mercury has the “largest” only because it’s moving faster than the others.
😐
Has the trajectory of the comet remnant altered from the trajectory of the original pathway to any measurable degree?
@me
> Newtonian physics got 12 astronauts to the Moon and back safely …
… and the 6 astronauts who piloted the Command Module around the moon. :-]
rikgheysens says:
November 30, 2013 at 10:09 am
But it is unclear for me if with the formula “d = 1.26 R_M (…)” the Roche-limit ‘d’ starts from the center of the Sun or from the surface.
From the center.
This webpage http://www.asterism.org/tutorials/tut25-1.htm is more clear, where ‘L_R’ (Roche-limit) starts obviously from the center.
The standard formula of the RL is RL=A (dSun/dComet)^(1/3) [in radii]. With density Sun dSun being 1.4 and density Comet dComet assumed to be 0.5, the formula becomes RL = A * 1.41 Rsun from the center or A* 0.41 Rsun from the surface. So, all depends on the constant A, which usually is taken as 1.26 for a rigid body. For a fluid [deformable] body A is larger, perhaps 2.4 or so [also dependent on the shape of the body]. So, a lot depends on whether the comet is deformable like a drop of water. A dirty snow ball or a rock really isn’t, and with that assumption ISON was outside the Roche-Limit. If it were inside it would likely break up into a series of pieces each of which would be a little comet, like Shoemaker-Levy: http://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9 and we would expect to see a ‘string of pearls’. So far we don’t see any [this may change] so my initial conclusion is that ISON was not tidally disrupted.
Game over…..again???? [/sarc
lsvalgaard says:
November 30, 2013 at 9:34 am
___
Wonder how solar wind and heliospheric parameters might be effecting comets orbit or incidence rate and you know stuff.
Below an example from CHANDRA observations during min and max.
Like this..
Solar system X-rays from charge exchange processes
K. Dennerl1,, C.M. Lisse2, A. Bhardwaj3, D.J.Christian4, S.J. Wolk5, D. Bodewits6, T.H. Zurbuchen7,
M. Combi7, and S. Lepri7
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/91180/324_ftp.pdf?sequence=1
..Bodewits et al. (2007) analyzed the X-ray spectra of all the comets, eight in total,
which were studied with the Chandra X-ray observatory in the period
2000 to 2006, covering the transition from solar maximum to solar minimum.
Figure 3a shows the (background subtracted raw) spectra of all
the comets, and Figs. 3b, c show at which ecliptic latitude and phase in the
solar cycle the spectra were observed. It is immediately obvious that there
are spectral differences.
In Fig. 3a, three spectral bands are indicated, dominated by
emission from (i) C V, CVI, NVI (‘C+N’), (ii) by OVII,
and (iii) by O VIII ions, and the spectra are arranged so that, from top to bottom,
flux is systematically shifted from lower to higher energy bands.
The quantitative results of the spectral fits clearly show that the flux in the C+N band
is anticorrelated to that in the O VIII band (Fig. 3d), indicating that the comets were
exposed to different solar wind conditions.
As can be seen in Figs. 3b and 3c, all the comets which were observed at high
latitudes happened to be there during solar maximum, when the equatorial solar wind
had expanded into these regions. This implies that, until 2006, Chandra had not observed
any comet exposed to the polar wind. This situation changed in October 2007, during solar
minimum, when the nucleus of comet 17P/Holmes experienced a spectacular outburst, which increased its dust and gas outflow and optical brightness by almost a million times
within hours, from under 17 mag to 3 mag, making it by far the optically brightest comet observable by Chandra since its launch. At the time, comet 17P/Holmes was located at a
sufficiently high heliographic latitude (19◦) to be exposed to the polar wind at solar minimum.
It was thus expected
that this comet would exhibit considerably different X-ray
properties, and in fact this was observed: 17P/Holmes became
the first comet where Chandra did not detect any significant X-ray emission at all
(Christian et al. 2010). The most likely explanation for this dramatic X-ray faintness is
that the polar wind was so diluted and its ionization so low that only very little X-ray flux
was generated by charge exchange at energies above ∼300 eV. An instrumental effect,
i.e., a loss of sensitivity, can definitively be ruled out, because only two months later,
another comet, 8P/Tuttle, was observed with Chandra, and this comet, at low latitude (3◦),
was clearly detected in X-rays (Christian et al. 2010).
While comets allow us to sample the solar wind heavy ion content at locations which are inaccessible by in-situ measurements…..
COMET ISON DIES … AGAIN
http://spaceweather.com/
Carla says:
November 30, 2013 at 11:18 am
Wonder how solar wind and heliospheric parameters might be effecting comets orbit or incidence rate and you know stuff.
You can stop wondering, the heliosphere does not affect the orbit or incidence rate.
Below an example from CHANDRA observations during min and max.
This is just one of your usual irrelevant rants. It is true that the comets can teach us about the solar wind [which was in fact predicted by Biermann from the existence of comet ion tails], but that is not relevant for the orbits or coming and going of comets.
Now wondering whether or not there is a relationship with the inclination of the heliocurrent sheet and the orbit of comets through the system?.
page3
Figure 3 b + c
of, Solar system X-rays from charge exchange processes
K. Dennerl1,, C.M. Lisse2, A. Bhardwaj3, D.J.Christian4, S.J. Wolk5, D. Bodewits6, T.H. Zurbuchen7,
M. Combi7, and S. Lepri7
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/91180/324_ftp.pdf?sequence=1
And ISON is ISOFF again…
http://wp.me/p7y4l-pAC
The article is implying that there is a cycle dependence on comets orbit through the solar system.
“””As can be seen in Figs. 3b and 3c, all the comets which were observed at high
latitudes happened to be there during solar maximum, when the equatorial solar wind
had expanded into these regions. This implies that, until 2006, Chandra had not observed
any comet exposed to the polar wind. This situation changed in October 2007, during solar
minimum, when the nucleus of comet 17P/Holmes experienced a spectacular outburst, which increased its dust and gas outflow and optical brightness by almost a million times
within hours, from under 17 mag to 3 mag, making it by far the optically brightest comet observable by Chandra since its launch. At the time, comet 17P/Holmes was located at a
sufficiently high heliographic latitude (19◦) to be exposed to the polar wind at solar minimum.”””
Carla says:
November 30, 2013 at 11:39 am
Now wondering whether or not there is a relationship with the inclination of the heliocurrent sheet and the orbit of comets through the system?.
Stop wondering, there is not any such relationship.
There is an effect on the comet ion tail, though. When the heliospheric current sheet sweeps over a comet, it steals [disconnects] the ion tail. A new tail starts to grow right away. The ion tail is VERY thin: if compressed to the density of ice, the whole tail would fit in a small suitcase, slides 8-9 of http://www.leif.org/research/On-Becoming-a-Scientist.pdf . To see the movies use http://www.leif.org/research/On-Becoming-a-Scientist.ppt
Carla says:
November 30, 2013 at 11:43 am
The article is implying that there is a cycle dependence on comets orbit through the solar system.
No, it does not. That is wishful thinking on your part. What the article says is that X-rays from comets were observed at solar maximum.
Anthony Watts says:
November 30, 2013 at 11:42 am
And ISON is ISOFF again…
http://wp.me/p7y4l-pAC
___
Don’t worry bout that Anthony.
They said comet Lovejoy was dead too. Then this year we were able to see ISON Encke and Lovejoy all in one FOV.
http://www.isoncampaign.org/files/images/blogpics/three_comets.jpg
lsvalgaard says:
November 30, 2013 at 12:09 pm
_____
Figure 3b is that of comet trajectory depicting shift from solar polar to ecliptic over solar cycle
Figure 3c is that of solar cycle 23 and relationship to trajectory
See Page 3
Fig. 3 b and c
“””As can be seen in Figs. 3b and 3c, all the comets which were observed at high
latitudes happened to be there during solar maximum, when the equatorial solar wind
had expanded into these regions. This implies that, until 2006, Chandra had not observed
any comet exposed to the polar wind. This situation changed in October 2007, during solar
minimum, when the nucleus of comet 17P/Holmes experienced a spectacular outburst, which increased its dust and gas outflow and optical brightness by almost a million times
within hours, from under 17 mag to 3 mag, making it by far the optically brightest comet observable by Chandra since its launch. At the time, comet 17P/Holmes was located at a
sufficiently high heliographic latitude (19◦) to be exposed to the polar wind at solar minimum.”””
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/91180/324_ftp.pdf?sequence=133
Carla says:
November 30, 2013 at 12:22 pm
Figure 3b is that of comet trajectory depicting shift from solar polar to ecliptic over solar cycle
Figure 3c is that of solar cycle 23 and relationship to trajectory…
I give up on you.
John Day,
What? According to Lewandowsky, nobody who participates at this site believes that there was a “real” moon program. So I guess you can’t used the Apollo program as positive evidence of Newtonian Celestial mechanics.
lsvalgaard says:
November 30, 2013 at 12:26 pm
Carla says:
November 30, 2013 at 12:22 pm
Figure 3b is that of comet trajectory depicting shift from solar polar to ecliptic over solar cycle
Figure 3c is that of solar cycle 23 and relationship to trajectory…
I give up on you.
————————
Ok..but we’ll be back..
sheeesh I’m just a stamp collector with an opinion.
Wallflower with only one headlight..
http://youtu.be/Zzyfcys1aLM
@Paul Westhaver
> According to Lewandowsky, nobody who participates at this
> site believes that there was a “real” moon program.
That is a crazy idea, so I guess that would make him a “lunatic”. 😐
Carla says:
November 30, 2013 at 1:06 pm
sheeesh I’m just a stamp collector with an opinion.
To have any worth, opinions must be reasoned…
Pamela Gray says:
November 30, 2013 at 9:00 am
Jurgen: Big ditto. I MUCH prefer straightforward discussion. Leif is a master at it.
>>>>>>>>
Dr. S. seems to always have at least one groupie with him.
I’m so jealous. My only groupies are bill collectors.
But, unfortunately, bill collectors tend to think for themselves….