Jump to content


Photo

Comet ISON - Cooked well done?

  • This topic is locked This topic is locked
412 replies to this topic

#1 Glen A W

Glen A W

    Viking 1

  • -----
  • Posts: 744
  • Joined: 04 Jul 2008
  • Loc: USA

Posted 25 November 2013 - 03:24 PM

It was looking so good the past couple of weeks, but now the news is sounding rather poor. They make it sound like the reduction in molecular emission lines is pretty telling about the comet having disintegrated.

Predictions, opinions, or prophecies, anyone?

http://www.skyandtel...l-Biter-2333...

http://www.isoncampaign.org/Present
 

#2 dyslexic nam

dyslexic nam

    Surveyor 1

  • *****
  • Posts: 1931
  • Joined: 28 Jan 2008
  • Loc: PEI, Canada

Posted 25 November 2013 - 03:32 PM

Booooo!
 

#3 Unknownastron

Unknownastron

    Viking 1

  • *****
  • Posts: 652
  • Joined: 06 Apr 2005
  • Loc: CatsEye Observatory,Rural Southern Oklahoma

Posted 25 November 2013 - 04:13 PM

I have learned one fact over years of comet predictions of too many comets to mention: some of the predictions are dead on, some are partly right, some are wrong. Comets remain too unpredictable to know what will happen until it does. Not that predictions should not be made, just that scientific study of comets is at a similar level to weather predictions a century or more ago. Trying to predict anything more than a very short time in the future is not reliable.
Clear skies and clean glass,
Mike
 

#4 djeber2

djeber2

    Apollo

  • *****
  • Posts: 1374
  • Joined: 02 Jul 2004
  • Loc: Cloudy Midwest

Posted 25 November 2013 - 08:25 PM

Glen, thanks for the articles, does not sound promising at this time. I am glad I saw it when I did.
 

#5 BrooksObs

BrooksObs

    Viking 1

  • -----
  • Posts: 790
  • Joined: 08 Dec 2012

Posted 25 November 2013 - 10:55 PM

Watch the SOHO images November 27 to 29 , paying particular attention to the size of the camera's "bloom spikes" relative to the comet's head. Their dimensions are indicative of the comet's true brilliance at the time. The longer the bloom spikes, the brighter the comet is. When in the camera's field of view, brilliant objects like Venus (at superior conjunction) will have bloom spikes that span a large part camera's field. If ISON's spikes are very long on the 28th and remain fairly large throughout the 29th, then expect a show in the morning sky beginning toward the end of next week. If not...oh well.

If you are unsure what to be looking for on the SOHO images, take a look back at Comet Lovejoy's SOHO image loops. I'll try posting my interpretation of what I'm seeing (or not seeing!) at some point during the 28th, here on Cloudy Nights.

BrooksObs
 

#6 StarWars

StarWars

    Mr. Postmaster Man

  • *****
  • Posts: 26479
  • Joined: 26 Nov 2003
  • Loc: At the Gym >Spudtastic<

Posted 25 November 2013 - 11:27 PM



Most likely Cooked .... :grin:
730,000 miles from the Sun is Toasty close... :mrevil:
 

#7 Tonk

Tonk

    Fly Me to the Moon

  • *****
  • Posts: 7078
  • Joined: 19 Aug 2004
  • Loc: Leeds, UK, 54N

Posted 26 November 2013 - 05:29 AM

Today on Comets-ML (yahoo group) the profesional astronomers are discussing the meaning of the rapid drop in production of various volatiles as measured using millimeter wavelength radio telescopes. Many are suggesting that the nucleus is now breaking up. This is backed up with some other experiments but yet others don't appear to be indicating this (possible lack of resolution and the effect of time dependency when looking at visual wavelenght data confuses things. Whereas millimeter wavelenth data is measuring events happening now)
 

#8 bartlebobton

bartlebobton

    Lift Off

  • -----
  • Posts: 3
  • Joined: 26 Nov 2013

Posted 26 November 2013 - 09:07 AM

Hi ...

I tripped over this site through my excitement over Comet Ison... From my very very limited school boy physics... If you have an object moving through space at 60miles per/sec...that is anticipated to increase to a speed perhaps 200 miles p/sec ...why would anyone be surprised if Ison broke up... The friction at those speeds must be quite a force on an object composed of ice and rock, factor in the gravitational pull of the sun + temperature... why would it be a surprise to anyone if the comet does not pull through...and simply breaks up....
Reading some articles, not on these boards, makes me think astronomy is an art form and not a science...

Fingers and legs crossed though.... Hall (Hale) Bop was quite special...I was sad to see it go...there is something quite magical about it...
 

#9 MessiToM

MessiToM

    Viking 1

  • *****
  • Posts: 886
  • Joined: 21 Dec 2009
  • Loc: Huntingdon PA

Posted 26 November 2013 - 09:41 AM

Umm.......no ^. It isn't like this is a 2 foot wide snowball ISON is several miles wide and may have enough material to burn off a lot and still be intact. Also. Where do you think FRICTION happens in space? There isn't any atmosphere.


Also. If this breaks up pre rather than post periphelon I will be SO bummed out!
 

#10 Octans

Octans

    Explorer 1

  • -----
  • Posts: 66
  • Joined: 13 Aug 2009
  • Loc: Santa Barbara, CA, USA

Posted 26 November 2013 - 09:46 AM

Hi ...

I tripped over this site through my excitement over Comet Ison... From my very very limited school boy physics... If you have an object moving through space at 60miles per/sec...that is anticipated to increase to a speed perhaps 200 miles p/sec ...why would anyone be surprised if Ison broke up... The friction at those speeds must be quite a force on an object composed of ice and rock, factor in the gravitational pull of the sun + temperature... why would it be a surprise to anyone if the comet does not pull through...and simply breaks up....
Reading some articles, not on these boards, makes me think astronomy is an art form and not a science...

Fingers and legs crossed though.... Hall (Hale) Bop was quite special...I was sad to see it go...there is something quite magical about it...


Friction isn't really a factor since it's passing through a near vacuum -- the solar wind / corona of the Sun is very tenuous and is negligible when compared to other factors like the heat and tidal forces. I don't think it's so much that everyone would be surprised if it broke up as that everyone's still holding onto hope that it survives, given that we seen comets like C/2011 W3 (Lovejoy) in the past.
 

#11 dyslexic nam

dyslexic nam

    Surveyor 1

  • *****
  • Posts: 1931
  • Joined: 28 Jan 2008
  • Loc: PEI, Canada

Posted 26 November 2013 - 09:57 AM

And for the record, I haven't yet read a post on ISON's possible/probable demise that expresses surprise. More like disappointment. People are simply hoping that ISON pulls through and puts on an amazing show.
 

#12 Tyranthrax

Tyranthrax

    Ranger 4

  • -----
  • Posts: 322
  • Joined: 22 Apr 2013
  • Loc: Tampa, FL

Posted 26 November 2013 - 10:20 AM

when ever I root for a team or get my hopes up for a win I am like the kiss of death on that team. I've been chering for this thing for a few months now. . . I base my predition on no science wat so ever, just my record. I hear a fat lady warming up for ISON.
 

#13 bartlebobton

bartlebobton

    Lift Off

  • -----
  • Posts: 3
  • Joined: 26 Nov 2013

Posted 26 November 2013 - 10:35 AM

Hey... thanks for the friction/atmosphere lesson.... Am I right in saying there is resistance from the solar wind(s)...but it's not significant.... Perhaps that's a bit of generalisation ....BB
 

#14 swalker

swalker

    Imaging Editor - Sky & Telescope

  • *****
  • Posts: 1494
  • Joined: 22 Jan 2007
  • Loc: 42.9225°N, 71.2242°W

Posted 26 November 2013 - 11:32 AM

Don't write off the comet just yet. While those science observations are discouraging, we'll all know how it will shape up come Thursday. It does make for some late drama, that's for sure...
 

#15 MessiToM

MessiToM

    Viking 1

  • *****
  • Posts: 886
  • Joined: 21 Dec 2009
  • Loc: Huntingdon PA

Posted 26 November 2013 - 11:49 AM

Thats for sure. A nail biter!

bartlebobton watch this .gif of solar wind affecting ISON and ENCKE
http://spaceweather....op_hi1a.gif?...
 

#16 boandpokey

boandpokey

    Ranger 4

  • *****
  • Posts: 315
  • Joined: 25 Jul 2013
  • Loc: Auburndale, Fl

Posted 26 November 2013 - 11:58 AM

all signs point to disintegration what a shame. I never got to see it. the weather here in the nonsunshine state the last 2 weeks has been terrible
 

#17 GlennLeDrew

GlennLeDrew

    Voyager 1

  • *****
  • Posts: 10508
  • Joined: 17 Jun 2008
  • Loc: Ottawa, Ontario, Canada

Posted 26 November 2013 - 12:34 PM

The matter of 'friction' has been partly addressed, that being the the solar wind is a very very good vacuum. The solar wind, blowing at up to 400 km/s, will have a virtually instantaneous impact on the atoms and molecules driven off the nucleus, they being accelerated to the solar wind speed in very short order. For the dust particles, as we progress up in size from the really fine stuff to millimeter-size bits, the acceleration becomes progressively slower. For instance, the bits which result in meteor showers (when intersected by Earth) basically travel along the comet's orbit for years, gradually dispersing into an increasingly wide stream.

As to the gravitational force of the Sun, its only impact is the tidal stress resulting from the difference in attraction between the day and night sides on the comet. The day side is attracted more strongly than the opposite side, and this stress can pull the body apart. This is what happened to comet Shoemaker-Levy 9 when it passed very near to Jupiter not long before before its final plunge into Jove's atmosphere.

If you were to follow the comet's path--but with very good thermal protection--even at perihelion you would be in free fall and hence feel weightless. If your feet were pointing at the Sun, they would be attracted a tiny bit more strongly than would your head, but you would not feel this awfully slight stretching over a mere 6 feet. (Near the event horizon of a black hole, though, you would be ripped apart.) Over an object diameter of some kilometres, however, the gravitational gradient and hence tidal stress is sufficient to overcome the comet's weak self gravity and internal cohesion.
 

#18 Tonk

Tonk

    Fly Me to the Moon

  • *****
  • Posts: 7078
  • Joined: 19 Aug 2004
  • Loc: Leeds, UK, 54N

Posted 26 November 2013 - 01:46 PM

The news as of this afternoon is ISON's brightness has stopped declining and is showing a very slow rise. However one commentator states its only showing brightness curve of a slowly expanding dust cloud (Comets ML)

Its now entering the FOV of the STEREO-B COR2 camera (bottom left)

http://stereo.gsfc.n...131126_15392...
 

#19 boandpokey

boandpokey

    Ranger 4

  • *****
  • Posts: 315
  • Joined: 25 Jul 2013
  • Loc: Auburndale, Fl

Posted 26 November 2013 - 02:15 PM

http://sohowww.nasco...024/latest.html

is that ISON, the faint fuzzy dot in the lower left??
 

#20 boandpokey

boandpokey

    Ranger 4

  • *****
  • Posts: 315
  • Joined: 25 Jul 2013
  • Loc: Auburndale, Fl

Posted 26 November 2013 - 02:21 PM

Tonk

thanks.. either way. very unimpressive compared to Lovejoy
 

#21 Tonk

Tonk

    Fly Me to the Moon

  • *****
  • Posts: 7078
  • Joined: 19 Aug 2004
  • Loc: Leeds, UK, 54N

Posted 26 November 2013 - 02:34 PM

http://sohowww.nascom.nasa.gov/data/realtime/c3/1024/latest.html

is that ISON, the faint fuzzy dot in the lower left??


No you have wrong spacecraft and wrong camera - you have the SOHO LASCO C3 camera - see my link above - its the STEREO-B COR2 camera
 

#22 boandpokey

boandpokey

    Ranger 4

  • *****
  • Posts: 315
  • Joined: 25 Jul 2013
  • Loc: Auburndale, Fl

Posted 26 November 2013 - 02:36 PM

well it should be visible in that one also???
 

#23 Tonk

Tonk

    Fly Me to the Moon

  • *****
  • Posts: 7078
  • Joined: 19 Aug 2004
  • Loc: Leeds, UK, 54N

Posted 26 November 2013 - 02:38 PM

No the FOV and position (direction to the sun) are entirely different between the two craft and their cameras

It will appear in SOHO C3 but not just yet

Here are some nice graphics showing when, where in each available SOHO, STEREO-A, STEREO-B camera

http://stereo-ssc.na...gov/comet_ison/
 

#24 Tom Laskowski

Tom Laskowski

    Vostok 1

  • -----
  • Posts: 155
  • Joined: 28 Apr 2008
  • Loc: South Bend, Indiana, USA

Posted 26 November 2013 - 02:45 PM

http://sohowww.nasco...024/latest.html

is that ISON, the faint fuzzy dot in the lower left??


I could be wrong, but the fuzzy thing in the image is M4 and the bright star to the left is Antares.
 

#25 bartlebobton

bartlebobton

    Lift Off

  • -----
  • Posts: 3
  • Joined: 26 Nov 2013

Posted 26 November 2013 - 03:19 PM

Hi Glenn... thanks for taking the time to explain to me a little bit more friction, that's really informative...much appreciated... BB
 






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics