[LMB] OTish: A smartass response to an APOD (Astronomy Picture of the Day)

mtraber251 mtraber251 at earthlink.net
Tue Sep 13 11:18:57 BST 2011

On 9/13/2011 2:07 AM, A. Marina Fournier wrote:
> http://apod.nasa.gov/apod/ap110912.html shows a Martian table-sized rock with a coating of white on it.
> Under the photo is a question:  Why does this Martian rock have so much zinc?
> My response: to keep from getting sunburnt, of course. Why else would it have white goop smeared over it?

I would almost surmise that the surface is oxidizing and may actually be 
alumina not zinc based even though it has a high %age of zinc locally, 
or the surface may be thermally different enough from the air and that 
may actually be ice [water or some other chemical] depositing on the 
surface. It could even be the surface subliming and just diffracting 
light in a manner to appear white from funky light refraction.

Just because a particular chemical is in high percentage locally does 
not mean that it is that element specifically. Apparently there is a 
fair amount of Fair Witness in me.

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