[meteorite-list] NASA Announces Comet Encounter News Conference

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Mon, 22 Nov 2010 11:03:07 -0700
Message-ID: <A0CBF74796F44405BF5A9500A9EB25C7_at_bellatrix>

It is 100% certain that comets are not hot inside. Surface temperatures
depend in part on the emissivity of the material; these low albedo surfaces
might reach temperatures of a few tens of degree Celsius, if they are in a
passive area where you don't have evaporation carrying away heat.

I think you are misreading the report. The carbon dioxide jets are not being
driven by water vapor. Water vapor is seen in the jets of other comets. In
the case of Hartley 2, the jets are CO2, which are able to eject still
frozen water crystal aggregates. While some of these were of a centimeter
scale, they were extremely low mass, which is why they didn't damage the
spacecraft. They were the SIZE of hailstones, but not the DENSITY of
hailstones.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: <cdtucson at cox.net>
To: <meteorite-list at meteoritecentral.com>; "Bob King" <nightsky55 at gmail.com>
Sent: Monday, November 22, 2010 10:44 AM
Subject: Re: [meteorite-list] NASA Announces Comet Encounter News Conference


> Hi Bob.
> Perhaps you did not read the NASA link I provided in my previous post.
> Here it is in case you missed it;
> http://www.foxnews.com/scitech/2010/11/19/spacecraft-flies-past-snowstorm-comet/
>
> Again, all do respect here.
>
> To be clear my questions here relate to gaining the knowledge of what
> rocks to look for that might be of a cometary origin. Not to knock others
> opinions. I just want logical answers.
> The link does say they think it is "water ice" as opposed to other
> substances.
> They go on to say that "jets of carbon dioxide *appear to be* fueled by
> water vapor. Vapor is the evaporation of boiling liquid water. But later
> say there are also large hailstone chunks to boot.
> I think it looks like hot dust (smoke) .
>
> They say some of the hailstorm of "Fluffy Ice" that hit the spacecraft may
> have been between the size of a golf ball and a basketball. This with NO
> damage to the spacecraft?
> Dr. A. Hearn also points out "how different Comets are from one another".
> Aw Ha moment here? They are different!
>
> You ask. How could they stay hot?
> That is the big question.
> I suppose it depends upon what they are made of. Iron might stay hot
> longer than mica for example.
> And or, Perhaps they contain some source of renewable energy source within
> them? . A source that is yet known to us?
> How do we know whether they are cooling or not?
> That coupled with the fact that all things take time.
> Look no farther than the published cooling rates of iron meteorites.
> The Tucson iron meteorite is said to not display the widmanstten pattern
> on an etched surface primarily because in spite of the fact that it
> contains plenty of nickel, it cooled too fast.
> This cooling rate has been calculated for the Tucson Iron ring meteorite
> to be in the order of 1 degree C per one thousand years. This again is
> considered a rapid cooling rate.
> No, nothing makes much sense if you believe what they say that hailstones
> the size of golf balls to basketballs hit this craft. It had to of been
> smoke from the intense heat of this comet to have not damaged the craft.
> ice and even melted ice in the form of water at 27K miles per hour would
> have damaged the craft.
> Incidentally , I took a piece of coal in the dark and illuminated it.
> Sorry, but it looks nothing like the close-up pics of Hartley 2 and that
> is the comet we are talking about here. No antique distant pics from the
> past can compare with these new pics. We are in a new age of discovery and
> should give up these old and possibly obsolete photos and theories of the
> past.
> One more thing.
> If these so called "infrared spectrometers" tell us what this Comet is
> made of then I would love to hear it? Please spare me the Fluffy ice
> though. What other minerals are abundant on comet hartley 2? Thanks.
Received on Mon 22 Nov 2010 01:03:07 PM PST