Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Howard Wu]

Primer follow up: Theory is that a shell of comets surround the solar system in the Oort cloud past Neptune, and then ocassionally one is disturb into falling into the inner solar system. There was a hypothesis proposed that there was a dark companion star to the sun with an ecentric orbit of 26 million years that rains down comets periodically causing episodic extinctions. Look up "Nemesis" for more info.
 
HowardRon Baalke <[EMAIL PROTECTED]> wrote:
> > I know I should research this myself but I hope I can get a relatively brief > answer upon which I can look further into this question if deemed worthwhile. > How does a small object like a comet, especially, travel for billions of > years constantly venting and releasing matter continue to exist? Why doesn't > it dissipate into virtual nothingness?> Some comets have been observed to split apart. SOHO has observed many of the sun grazersto fall apart entirely. But not all comets will just disappear. They'll eventuallylose all of their volatiles and become a burnt-out comet. At that point they willresemble an asteroid. There are a few asteroids that we suspect to be former comets -they are in very elongated orbits, but have not formed a tail.Comet Wild 2 is considered to be a 'fresh' comet. It has been in
 the innersolar system for only about 30 years. Prior to 1974, Comet Wild 2 was in a distant orbitthat crossed the orbits of Jupiter and Uranus. A close flyby of Jupiter in September 1974radically perturbed its orbit closer to the Sun. Its orbits now crosses the orbit of Mars at perihelion and the orbit at Jupiter at aphelion. Being closer to the Sun means it now a much brighter object, and Paul Wild discovered the comet in 1978.Ron Baalke__Meteorite-list mailing list[EMAIL PROTECTED]http://www.pairlist.net/mailman/listinfo/meteorite-list  
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Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Howard Wu]

Primer follow up: Theory is that a shell of comets surround the solar system in the Oort cloud past Neptune, and then ocassionally one is disturb into falling into the inner solar system. There was a hypothesis proposed that there was a dark companion star to the sun with an ecentric orbit of 26 million years that rains down comets periodically causing episodic extinctions. Look up "Nemesis" for more info.
 
HowardRon Baalke <[EMAIL PROTECTED]> wrote:
> > I know I should research this myself but I hope I can get a relatively brief > answer upon which I can look further into this question if deemed worthwhile. > How does a small object like a comet, especially, travel for billions of > years constantly venting and releasing matter continue to exist? Why doesn't > it dissipate into virtual nothingness?> Some comets have been observed to split apart. SOHO has observed many of the sun grazersto fall apart entirely. But not all comets will just disappear. They'll eventuallylose all of their volatiles and become a burnt-out comet. At that point they willresemble an asteroid. There are a few asteroids that we suspect to be former comets -they are in very elongated orbits, but have not formed a tail.Comet Wild 2 is considered to be a 'fresh' comet. It has been in
 the innersolar system for only about 30 years. Prior to 1974, Comet Wild 2 was in a distant orbitthat crossed the orbits of Jupiter and Uranus. A close flyby of Jupiter in September 1974radically perturbed its orbit closer to the Sun. Its orbits now crosses the orbit of Mars at perihelion and the orbit at Jupiter at aphelion. Being closer to the Sun means it now a much brighter object, and Paul Wild discovered the comet in 1978.Ron Baalke__Meteorite-list mailing list[EMAIL PROTECTED]http://www.pairlist.net/mailman/listinfo/meteorite-list  
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Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Sterling K. Webb]

 Hi,

 A comet is presumed to have spent most of its billions of years out in
 the cold beyond the planets. Something -- a gravitational encounter --
 disturbs its orbit and it falls into the inner system, probably by stages,
 with Jupiter as a big player in this game.
 Once a comet reaches an orbit in the inner system, it's pretty much
 doomed. Survival times for a icy body in the inner system is limited to a
 few hundred thousand years at most. Of course, once all the volatiles are
 gone, a rocky, dusty and much smaller body may remain to be mistaken for an
 asteroid.
 This has happened, that an "asteroid" suddenly develops a weak coma, or
 a comet loses it coma and is seen as an asteroid. Asteroid 1979VA turned out
 to be Comet Wilson-Harrington 194 III, lost and rediscovered as an
 "asteroid."
 The Zodaical Light is produced by trillions of tons of dust in the inner
 system orbital plane. This dust would be rapidly (~50,000 years) dissipated
 if it were not constantly being re-supplied from somewhere. Comets are good
 bet.
 A good case has been made for Comet Enke and assorted other large bodies
 in the inner system to be the breakup products of a very large comet (70
 km.) that got trapped in the inner system only 50,000 to 100,000 years ago.
 Tracing the evolution of the orbits of these bodies backwards for that
 length of time puts them all in the same orbit originally.
 Now, that would nice to watch! A 100 kilometer comet in an inner system
 orbit, what a show!


 Sterling K. Webb
 -

 [EMAIL PROTECTED] wrote:

  Hi all,

  I know I should research this myself but I hope I can get a
  relatively brief
  answer upon which I can look further into this question if deemed
  worthwhile.
  How does a small object like a comet, especially, travel for
  billions of
  years constantly venting and releasing matter continue to exist?
  Why doesn't
  it dissipate into virtual nothingness?

  Bill Kieskowski


 Sterling K. Web  wrote:

 >  Hi,
 >
 >  I was fascinated by the first flyby image that was
 >  released (the one featured on APOD). Despite its generally
 >  fuzzy appearance, there is a lot of detail buried in there
 >  that I hope we'll get to see when the wizards are through
 >  massaging the images for detail and content.
 >  I took a copy of that image and squeezed it as hard as I
 >  could. I doubled the spacing of all the pixels and filled in
 >  the intermediate spaces with eight-way median values, twiddled
 >  with its histogram to re-distribute the greyscale values to a
 >  more normal distribution, then stomped all over it with a
 >  square sharpness filter.
 >  I found that is LOTS of detail there, although my
 >  ham-handed efforts left some messy artifacts. For example, the
 >  "crater-like" circular features do not have uniformly shaded
 >  bottoms. They're not smooth (nor flat I would guess), but
 >  usually show a single deep dark conoid pit that's probably a
 >  large primary vent for outgassing.
 >  The walls of these "crater-like" features show some linear
 >  features, as if the depressions had formed by a slump-like
 >  collapse, perhaps from the rapid removal of material from
 >  beneath the "slump" by outgassing. Lots of tantalizing
 >  features not quite sharp enough to interpret. I'm left with
 >  the impression of a surface with lots of varying contours.
 >  Many of the smaller high contrast features seem to be
 >  albedo-related, as if between light and dark materials,
 >  perhaps at smaller "un-slumped" vents.
 >  If anyone's interested, you can view this roughly enhanced
 >  image at:
 >  .
 >
 >
 >  Sterling K. Webb
 >
 ---
 >
 >  Ron Baalke wrote:
 >
 >   I've added an animation of the Comet Wild 2 flyby
 >   images taken by
 >   Stardust to the Stardust website.
 >   Included is a chart from the Dust Flux Instrument
 >   showing
 >   the particle impacts on the spacecraft during the
 >   flyby, and
 >   another chart showing the spacecraft thruster
 >   activity:
 >
 >   http://stardust.jpl.nasa.gov/news/status/040106.html
 >
 >   You can view the animation directly from here:
 >
 >   http://stardust.jpl.nasa.gov/images/w

Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Ron Baalke]

> 
> I know I should research this myself but I hope I can get a relatively brief 
> answer upon which I can look further into this question if deemed worthwhile. 
> How does a small object like a comet, especially, travel for billions of 
> years constantly venting and releasing matter continue to exist? Why doesn't 
> it dissipate into virtual nothingness?
> 

Some comets have been observed to split apart. SOHO has observed many of the sun 
grazers
to fall apart entirely.  But not all comets will just disappear.  They'll eventually
lose all of their volatiles and become a burnt-out comet.  At that point they will
resemble an asteroid. There are a few asteroids that we suspect to be former comets -
they are in very elongated orbits, but have not formed a tail.

Comet Wild 2 is considered to be a 'fresh' comet.  It has been in the inner
solar system for only about 30 years.   Prior to 1974, Comet Wild 2 was in a distant 
orbit
that crossed the orbits of Jupiter and Uranus.  A close flyby of Jupiter in September 
1974
radically perturbed its orbit closer to the Sun.  Its orbits now 
crosses the orbit of Mars at perihelion and the orbit at Jupiter at aphelion.   
Being closer to the Sun means it now a much brighter object, and Paul Wild 
discovered the comet in 1978.

Ron Baalke

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RE: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Bernhard \"Rendelius\" Rems]

This is a layman's answer:

A comet only looses substantial matter when close(r) to the sun. So yes,
after some time he disintegrates, but this can take a long time,
especially when he's big. Some comets' orbits are even disturbed in a
way that they drop into the sun - they are gone then, naturally.

  _  

Best regards,
Bernhard "Rendelius" Rems 

CEO RPGDot Network 

 
This outgoing mail has been virus-checked.

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Thursday, January 08, 2004 9:25 AM
To: Sterling K. Webb
Cc: [EMAIL PROTECTED]
Subject: Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

Hi all,

I know I should research this myself but I hope I can get a relatively
brief 
answer upon which I can look further into this question if deemed
worthwhile. 
How does a small object like a comet, especially, travel for billions of

years constantly venting and releasing matter continue to exist? Why
doesn't 
it dissipate into virtual nothingness?

Bill Kieskowski



 
>  Hi,
> 
>  I was fascinated by the first flyby image that was
>  released (the one featured on APOD). Despite its generally
>  fuzzy appearance, there is a lot of detail buried in there
>  that I hope we'll get to see when the wizards are through
>  massaging the images for detail and content.
>  I took a copy of that image and squeezed it as hard as I
>  could. I doubled the spacing of all the pixels and filled in
>  the intermediate spaces with eight-way median values, twiddled
>  with its histogram to re-distribute the greyscale values to a
>  more normal distribution, then stomped all over it with a
>  square sharpness filter.
>  I found that is LOTS of detail there, although my
>  ham-handed efforts left some messy artifacts. For example, the
>  "crater-like" circular features do not have uniformly shaded
>  bottoms. They're not smooth (nor flat I would guess), but
>  usually show a single deep dark conoid pit that's probably a
>  large primary vent for outgassing.
>  The walls of these "crater-like" features show some linear
>  features, as if the depressions had formed by a slump-like
>  collapse, perhaps from the rapid removal of material from
>  beneath the "slump" by outgassing. Lots of tantalizing
>  features not quite sharp enough to interpret. I'm left with
>  the impression of a surface with lots of varying contours.
>  Many of the smaller high contrast features seem to be
>  albedo-related, as if between light and dark materials,
>  perhaps at smaller "un-slumped" vents.
>  If anyone's interested, you can view this roughly enhanced
>  image at:
>  <http://www.bhil.com/~kelly/wild2.html>.
> 
> 
>  Sterling K. Webb
>

---
> 
>  Ron Baalke wrote:
> 
>   I've added an animation of the Comet Wild 2 flyby
>   images taken by
>   Stardust to the Stardust website.
>   Included is a chart from the Dust Flux Instrument
>   showing
>   the particle impacts on the spacecraft during the
>   flyby, and
>   another chart showing the spacecraft thruster
>   activity:
> 
>   http://stardust.jpl.nasa.gov/news/status/040106.html
> 
>   You can view the animation directly from here:
> 
>   http://stardust.jpl.nasa.gov/images/w2_flyby1.gif
> 
>   Ron Baalke
> 
> 
> 
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Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[joseph_town]

Hi all,

I know I should research this myself but I hope I can get a relatively brief 
answer upon which I can look further into this question if deemed worthwhile. 
How does a small object like a comet, especially, travel for billions of 
years constantly venting and releasing matter continue to exist? Why doesn't 
it dissipate into virtual nothingness?

Bill Kieskowski



 
>  Hi,
> 
>  I was fascinated by the first flyby image that was
>  released (the one featured on APOD). Despite its generally
>  fuzzy appearance, there is a lot of detail buried in there
>  that I hope we'll get to see when the wizards are through
>  massaging the images for detail and content.
>  I took a copy of that image and squeezed it as hard as I
>  could. I doubled the spacing of all the pixels and filled in
>  the intermediate spaces with eight-way median values, twiddled
>  with its histogram to re-distribute the greyscale values to a
>  more normal distribution, then stomped all over it with a
>  square sharpness filter.
>  I found that is LOTS of detail there, although my
>  ham-handed efforts left some messy artifacts. For example, the
>  "crater-like" circular features do not have uniformly shaded
>  bottoms. They're not smooth (nor flat I would guess), but
>  usually show a single deep dark conoid pit that's probably a
>  large primary vent for outgassing.
>  The walls of these "crater-like" features show some linear
>  features, as if the depressions had formed by a slump-like
>  collapse, perhaps from the rapid removal of material from
>  beneath the "slump" by outgassing. Lots of tantalizing
>  features not quite sharp enough to interpret. I'm left with
>  the impression of a surface with lots of varying contours.
>  Many of the smaller high contrast features seem to be
>  albedo-related, as if between light and dark materials,
>  perhaps at smaller "un-slumped" vents.
>  If anyone's interested, you can view this roughly enhanced
>  image at:
>  .
> 
> 
>  Sterling K. Webb
>  ---
> 
>  Ron Baalke wrote:
> 
>   I've added an animation of the Comet Wild 2 flyby
>   images taken by
>   Stardust to the Stardust website.
>   Included is a chart from the Dust Flux Instrument
>   showing
>   the particle impacts on the spacecraft during the
>   flyby, and
>   another chart showing the spacecraft thruster
>   activity:
> 
>   http://stardust.jpl.nasa.gov/news/status/040106.html
> 
>   You can view the animation directly from here:
> 
>   http://stardust.jpl.nasa.gov/images/w2_flyby1.gif
> 
>   Ron Baalke
> 
> 
> 
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Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Sterling K. Webb]

 Hi,

 I was fascinated by the first flyby image that was
 released (the one featured on APOD). Despite its generally
 fuzzy appearance, there is a lot of detail buried in there
 that I hope we'll get to see when the wizards are through
 massaging the images for detail and content.
 I took a copy of that image and squeezed it as hard as I
 could. I doubled the spacing of all the pixels and filled in
 the intermediate spaces with eight-way median values, twiddled
 with its histogram to re-distribute the greyscale values to a
 more normal distribution, then stomped all over it with a
 square sharpness filter.
 I found that is LOTS of detail there, although my
 ham-handed efforts left some messy artifacts. For example, the
 "crater-like" circular features do not have uniformly shaded
 bottoms. They're not smooth (nor flat I would guess), but
 usually show a single deep dark conoid pit that's probably a
 large primary vent for outgassing.
 The walls of these "crater-like" features show some linear
 features, as if the depressions had formed by a slump-like
 collapse, perhaps from the rapid removal of material from
 beneath the "slump" by outgassing. Lots of tantalizing
 features not quite sharp enough to interpret. I'm left with
 the impression of a surface with lots of varying contours.
 Many of the smaller high contrast features seem to be
 albedo-related, as if between light and dark materials,
 perhaps at smaller "un-slumped" vents.
 If anyone's interested, you can view this roughly enhanced
 image at:
 .


 Sterling K. Webb
 ---

 Ron Baalke wrote:

  I've added an animation of the Comet Wild 2 flyby
  images taken by
  Stardust to the Stardust website.
  Included is a chart from the Dust Flux Instrument
  showing
  the particle impacts on the spacecraft during the
  flyby, and
  another chart showing the spacecraft thruster
  activity:

  http://stardust.jpl.nasa.gov/news/status/040106.html

  You can view the animation directly from here:

  http://stardust.jpl.nasa.gov/images/w2_flyby1.gif

  Ron Baalke



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RE: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Jose Campos]

Yes Ron, offcourse the spacecraft was well inside the coma at the time these
series of images were taken;
 The double image effect is more noticeable on the 6th and 7th
images; however, my impression of a very faint trace of a possible short fan
tail, came from viewing the first 3 images.
 But in all probability, you are quite right. Thanks.
 José Campos


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Ron
Baalke
Sent: Thursday, January 08, 2004 1:29 AM
To: Meteorite Mailing List
Subject: Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2


>
>
> Hi Ron,
> Great, most interesting animation!
> It seems that there was a very faint trace of a short, fan-shaped coma,
seen
> from the comet's nucleous towards it's UPPER direction (as the picture is
> shown).

Bear in mind the spacecraft was well inside the coma when it took the
images.
The feature you noticed is an artifact of looking through the periscope - a
double image effect.

Ron Baalke

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Re: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Ron Baalke]

> 
> 
> Hi Ron,
> Great, most interesting animation!
> It seems that there was a very faint trace of a short, fan-shaped coma, seen
> from the comet's nucleous towards it's UPPER direction (as the picture is
> shown).

Bear in mind the spacecraft was well inside the coma when it took the images.
The feature you noticed is an artifact of looking through the periscope - a
double image effect.

Ron Baalke

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RE: [meteorite-list] Stardust Flyby Images of Comet Wild 2

[Jose Campos]

Hi Ron,
Great, most interesting animation!
It seems that there was a very faint trace of a short, fan-shaped coma, seen
from the comet's nucleous towards it's UPPER direction (as the picture is
shown).
Many thanks for sharing it with us.
José Campos

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Ron
Baalke
Sent: Thursday, January 08, 2004 12:33 AM
To: Meteorite Mailing List
Subject: [meteorite-list] Stardust Flyby Images of Comet Wild 2



I've added an animation of the Comet Wild 2 flyby images taken by
Stardust to the Stardust website.
Included is a chart from the Dust Flux Instrument showing
the particle impacts on the spacecraft during the flyby, and
another chart showing the spacecraft thruster activity:

http://stardust.jpl.nasa.gov/news/status/040106.html

You can view the animation directly from here:

http://stardust.jpl.nasa.gov/images/w2_flyby1.gif

Ron Baalke


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