[meteorite-list] NASA Announces Comet Encounter News Conference

From: Elizabeth Warner <warnerem_at_meteoritecentral.com>
Date: Mon, 22 Nov 2010 12:34:11 -0500
Message-ID: <4CEAA993.50004_at_astro.umd.edu>

With all due respect Carl, please stick to talking about meteorites
which you know about it and leave stuff about comets that you know
nothing about to the cometary scientists.

It is rather unfortunate that when scientists use or reuse everyday
terms like ice, that people interpret that to mean ice cubes like in
their freezer. When in fact, ice is the technical term for frozen
volatiles including H2O, CO2, etc... And how ice behaves in space is
going to be different than how it behaves in an atmosphere under
pressure and subject to gravitational forces.

If comets were in fact fiery hot, we would have several lines of
evidence showing that and we don't. All of the evidence shows that
comets are cold and that when close to the sun, the ices sublimate.
Which ices sublimate when is a factor of distance from the sun, how
"fresh" the comet is, and lots of details that get boring real fast.

Out in space, I can imagine that it is very easy to get fluffy large
snowflakes that we wouldn't see here on Earth. "Snowflakes" is also not
a good word to use, but we have no other words to describe the things we
are seeing, so we use the closest words that we have.

Why didn't these fluffy things damage the spacecraft? Mostly because
most of the fluffy things we were seeing were fairly close to the
nucleus and not 400 miles away like the spacecraft was. As the fluffy
aggregates of ice and dust get further away, the ices continue to
sublimate and the fluffy aggregate eventually breaks apart into the tiny
tiny dust particles.

Basically, we have spectroscopic maps (the distribution maps that have
been posted) showing both water vapor and water solids. They are not
coming from the same places on the comet.

I was going to point out how the Inuit have multiple words for snow only
to find out that they have no more than we do. The article though is
still interesting and.. relevant...
http://en.wikipedia.org/wiki/Eskimo_words_for_snow

Comets as objects are not something that we experience in our everyday
lives. Therefore, their parts and structures may not have everyday
equivalents. Therefore, we use words that are similar and closely
describe what we see and give those words new meanings. Another classic
example in astronomy is the use of the word umbra. It means shadow. When
early solar observers first saw sunspots, they thought those were
shadows they were seeing so they used shadow terminology. We know now
that sunspots are not shadows, but to come up with brand new words to
describe the parts of a sunspot... well, umbra and penumbra stuck.

Clear Skies!
Elizabeth Warner
EPOXI webmaster





cdtucson at cox.net wrote:
> Larry, Chris, All,
> All due respect here but, Smoke is very fine dust.
> To your point I must agree that the eraser example is perfect.
> see link to latest info about Comet Hartley 2;
>
> http://www.foxnews.com/scitech/2010/11/19/spacecraft-flies-past-snowstorm-comet/
>
> According to this news. They are now saying that this stuff spewing out of these jets is "fluffy ice".
> This seems to me to be a classic case of 'Manipulating the facts to fit their original hypothesis'?
> They think comets are icy.
> They claim that this material moving at 27,000 MPH did not cause damage to the craft because it is soft fluffy ice.
> I don't know just how fluffy ice can be but golf ball to basketball size "fluffy ice" objects hitting something while moving that fast does not sound like fun.
> Now on the other hand. If this is just smoke it is easier for me to understand why no damage was done to the craft when the craft flew through the debris left by the Comet..
> So, it in deed seems to me that as Larry pointed out this stuff is not ice but is smoke. We don't have to force this result to fit any ice theory.
> Further, in the pictures the jets appear to be everywhere. Not just at the tail end. And the reflected light appears to be illuminating parts of the surface equal to the brightness of the jets which would seem to indicate a highly reflective substance like metal.
> To further this theoretical possibility. In the only gathering of actual comet dust they were able to determine that a metallic mineral Manganese / silicate was in fact spewed out of the comet. This was later named "Brownleeite" and is now considered to be a new mineral.
> So, in Sum, this thing looks like it is spewing out smoke (very fine dust).
> Isn't this possible? Why does it have to be Ice? Many objects out in space are fiery hot. Hot stuff is out there. Look no farther than our own Sun. Why according to NASA do comets have to be cold? These pictures are the only close -ups we have and they say. This is one hot chicken leg.
> And the conclusion should not be forced. Let the facts speak for themselves. Sorry but, I think Ice is hard not fluffy. Especially at 27K miles per hour.
> IMHO.
> Carl
>
>
>
>
> ---- lebofsky at lpl.arizona.edu wrote:
>> Hi All:
>>
>> As far as I know, all we are seeing in the comet images in the jets is
>> dust. If you have fine dust particles and shine light on them, the
>> scattered light will make them stand out like that. One sees the effect in
>> a smokey room (or sports stadium) and I demonstrate this in a classroom by
>> clapping dusty chalkboard erasers together.
>>
>> Larry
>>
>>> Images can be deceiving. Certainly, the comet is not lit, except by
>>> sunlight. As appears to be common with comets, it has a surface coating,
>>> some sort of weathering, that results in an extremely low albedo. That
>>> isn't
>>> apparent in an image that has had its white and dark points adjusted for
>>> maximum clarity.
>>>
>>> I don't think there is any doubt that the body is very cold in its
>>> interior,
>>> and is made of some mixture of ices and stony material. The surface may
>>> well
>>> approach room temperature, which is what is driving the boiling away of
>>> ices
>>> that produces a coma.
>>>
>>> Chris
>>>
>>> *****************************************
>>> Chris L Peterson
>>> Cloudbait Observatory
>>> http://www.cloudbait.com
>>>
>>>
>>> ----- Original Message -----
>>> From: <cdtucson at cox.net>
>>> To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>; "Ron
>>> Baalke" <baalke at zagami.jpl.nasa.gov>
>>> Sent: Monday, November 15, 2010 2:46 PM
>>> Subject: Re: [meteorite-list] NASA Announces Comet Encounter News
>>> Conference
>>>
>>>
>>>> List,
>>>> I wonder if these new images will shed new light on the definition of
>>>> what
>>>> a comet is?
>>>> Typically the description includes the words frozen and ice in some
>>>> form.
>>>> But clearly based on the close-up visual images. It seems that this
>>>> thing
>>>> is far from being ice. In fact to me it appears to look more like a
>>>> fiery
>>>> hot briquette about ready to throw the steaks on to. It seems from the
>>>> photos that this thing is fully lit from the inside core to the
>>>> surface.
>>>> And could not possibly consist of ice in any of it's forms melted or
>>>> frozen. Well, maybe the surface stays wet and cold but the inside is far
>>>> from cold.
>>>> Hopefully this conference will alert us all with an update as to what
>>>> we
>>>> hunters need to be looking for. Because clearly it aint Ice. That's for
>>>> sure. But I am dying to find out what it is after all! It seems to me
>>>> we
>>>> should be looking for melted stuff. Really really melted stuff. Has
>>>> anyone
>>>> heard yet what they plan to say the interior is made up of?
>>>> My 2 more cents.
>>>> Carl
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Received on Mon 22 Nov 2010 12:34:11 PM PST