[meteorite-list] www.venusmeteorite.com - what are your opinions on this claim

From: lebofsky at lpl.arizona.edu <lebofsky_at_meteoritecentral.com>
Date: Thu, 15 Feb 2007 11:17:40 -0700 (MST)
Message-ID: <1607.128.196.250.86.1171563460.squirrel_at_timber.lpl.arizona.edu>

Hi Randall:

I will try to answer one of your questions.

I wish I could give you details on how to get meteorites off of Mars, but
this is something that I would have to talk to Jay Melosh about (if I can
keep him in place long wnough).

However, I can address the issue of asteroid/meteroid temperatures:

The temperature of an asteroid depends on: distance from the Sun, how fast
it is rotating, the nature of the surface material (rocky, dusty, high or
low albedo, composition [at some level]).

The closer it is to the Sun, the warmer. The dustier it is, the hotter it
gets, but cools down at night. The slower it rotates, the hotter it gets
at "noon" and the colder it gets at night. The dustier it is, the less the
heat of the Sun can penetrate into the inrerior and so the cooler the
inside stays.

"Typical" main-belt asteroids can get up to about 250 K at noon at the
sub-solar point, but will cool down to 125 K or so at night. Near-Earth
asteroids will get warmer as they approach the Sun, but they tend to be
rockier, which reduces the max temperature, but can still get warm to hot
depending on how close to the Sun the asteroid gets.

However, the "average" temperature will still be fairly low since the
interior is usually well insulated and the asteroid still probably spends
much of its time far from the Sun.

I hope this helps.

Larry

On Wed, February 14, 2007 11:13 am, Randall Gregory wrote:
> Mr. Webb,McCafferty and others.
>
>
> If you don't mind, I have a few more questions.
>
>
> Do you know of a facility that could perform 187Os/186Os ratios testing
> at a reasonable price?
>
>
> Would element variations and ratios in the fusion crust be indicative of
> extraterrestrial origin. In other words, would the capture and melting of
> space dust into the fusion crust, thus causing elemental variances be a
> good indicator?
>
> Do you know of any comparative analysis of the fusion crust/matrix that
> could be identified as high versus low atmospheric heating?
>
> Does rapid atmospheric heating alter the fusion crust differently than
> terrestrial heating?
>
>
> Do you know if artificial ablation has been compared to natural ablation
> on meteorites? I tried different types of heat on a sample that I
> fractured and found that an artificially heated sample created a very
> different type of fusion crust. The artificial crust was glassy and
> somewhat brittle.
>
> In the vacuum of space, all meteorids would receive solar radiation in
> varying degrees and cooled by space itself. Could the temperature of a
> near-earth meteroid be projected from it's mineral characteristics? In
> other words, we know meteorites are cold, but the question is how cold
> are they before they reach the Earth's atmosphere?
>
>
>
> Thanks,
>
>
> Randall
>
>
>
>
>
>
>
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Received on Thu 15 Feb 2007 01:17:40 PM PST