[X] My Assistant

[SigurRosFan]

Wow, Oppy's next stop ...

-----
For instance, it has seen fluid flow features in Victoria Crater just south of the equator, where NASA's Opportunity rover is trudging along the rim. The fractures appear to be surrounded by cemented rock on the eastern crater rim and floor.

One of NASA's goals for Opportunity is to get to that side of the crater. If it is able to get close enough, Opportunity might provide some microscopic observations of the rock to confirm whether the rock has been cemented together by fluid.
-----

- Underground pipes channelled water on Mars

[dvandorn]

Yes, but this is rather like Occam's Razor. There is no need to bring in extraordinary events here; the areas in Victoria where we see these linear features were originally outside of its rim. The crater has expanded via wall slump so that the walls have expanded *into* linear fault features, which more than likely pre-existed the crater. (In fact, I'd say they'd almost have to -- how many craters have you seen that have created faults tangential to their rims? Impacts more commonly create radial cracking than cracking transverse to the impact surge.)

I'm not saying that these fault features are definitely *not* associated with fluid flows. All I'm saying is that linear faults are fairly common on all of the rocky bodies we've observed (Earth, Moon, Mars and Venus) and in most cases these faults are tectonic in nature. Of the remaining sources of linear faulting that have been observed, only a relatively few are related to fluid flow.

So, if it turns out that Oppy can visit these ridges and they turn out not to show signs of fluid flow formation, that doesn't mean there aren't other locations on Mars where fluid flow faulting has occurred. And, conversely, if fluid flow *is* indicated in Victoria's linear faults, that doesn't mean that every similar set of faults we see on Mars were also formed in the same manner. Linear faults are just too common and have too many different causes for such generalizations to always be valid.

-the other Doug