[meteorite-list] Slow cooling rate of irons in space

[Chris Peterson]

Hi Sterling-

>From what I've read, there is actually a fair bit of doubt that Venus has a 
molten interior. The only reason to think it does is because of its 
similarity to Earth (in terms of size and density). But there's a lack of 
good understanding about formation details (such as isotope types and 
amounts), so quite a few planetary geologists (silly term, isn't it?) 
consider it very possible that the core of Venus froze a long time ago.

In any case, more information is needed. And the fact that Venus has a weak 
magnetic field doesn't mean it necessarily has a solid core (although that 
remains an important piece of evidence in favor of that scenario); core 
dynamos aren't well enough understood to know if a molten core always 
produces a magnetic field.

Chris

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


----- Original Message ----- 
From: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
To: "Rob McCafferty" <rob_mccafferty at yahoo.com>; 
<meteorite-list at meteoritecentral.com>
Sent: Saturday, September 05, 2009 10:21 PM
Subject: Re: [meteorite-list] Slow cooling rate of irons in space


Hi,

> Venus they're not sure about.

One thing I think we can be sure about is that
no one will ever use the phrase "so darn cold"
about Venus, as we stand next to a small creek
running with liquid lead and other low melting
point metals...

There are signs that may be recent activity on
Venus in some areas, but interpreting them
is in dispute. Generally, the surface of Venus
appears to have formed all at one time, crater
dated at 480 +/- 80 million years ago. The lack
of long-term change is attributed to the fact
that Venus's crust is, compared to the Earth's,
extremely thick and rigid, with no detectible
tectonic movement, recent mountain building,
or any of the other features of a "terrestrial"
planet. But, given the similarity in size, density
(and hence composition) to the Earth, few doubt
that Venus' core is as hot and active as our own.
It's just that nothing  (much) can punch its way
through that heavy crust.