[X] My Assistant

[dvandorn]

As I recall, the ambiguous results of the Viking landers' life detection experiments were explained at the time by postulating that the surface soils are highly enriched with extremely oxidized clays (I seem to recall descriptions of clays enriched with peroxides).

Nearly identical results were seen at both V1 and V2 sites, so, assuming that the results are explained by what was called "exotic soil chemistry," this chemistry would have to be widespread on Mars.

We now have some very good elemental analyses of the Martian soils, both from orbit and ground-truth from the MER rovers. In these analyses, clays seem not at all widespread, only appearing in very, very old outcrops that were presumably laid down during a very short geological timeframe during which non-acidic water was common on the Martian surface.

Soils in the Viking landing sites would appear, from the more advanced sensors we've flown since Viking, to be basaltic with admixtures of ferrous sulphates. Not exactly the exotic chemistry required to explain the Viking results.

So, the million-dollar question seems to be: if the Viking experiments can only be explained by *either* biotic processes that do not involve what we always considered the pre-requisite organic molecules, *or* by ubiquitous exotic chemistry in the soils that we're simply not seeing with more advanced instruments, which theory are we forced to accept as fact?

If neither, then what theory *does* account for the Viking results?

-the other Doug

[djellison]

And to add to this - the APXS's on MER can't detect hydrogen, and if your trying to find peroxides........

To carry on JR's analogy - It's like knowing how many of every letter EXCEPT E there are in a paragraph, and wondering what it means.

Doug

[chris]

And to add to this - the APXS's on MER can't detect hydrogen, and if your trying to find peroxides........

To carry on JR's analogy - It's like knowing how many of every letter EXCEPT E there are in a paragraph, and wondering what it means.

Doug

To put Doug's post another way:

T:17 N:17 A:17 R:15 O:15 I:11 D:11 Y:7 S:7 H:7 G:7 P:5 W:4 C:4 X:3 M:3 L:3 F:3 U:2 K:2 V:1 J:1

Chris

[ljk4-1]

Silly Question of the Day: When they designed Viking to look for
life on the Martian surface, why didn't they include instruments to
fully analyze the materials to separate and detect the inorganic
elements?

Didn't they want to know what the Martian surface was made of
outside of the life issue? I am still amazed at how much of the
results were left to guesswork.