Not Pits, Tubes

[Fraser]

Remember those amazing images of open pits on Mars? NASA's Mars Reconnaissance Orbiter has come back around and taken another image of one of the features, and this time it spotted a wall on one side. ...

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[John Mendenhall]

Still deep enough to be a flying saucer hangar.

[thothicabob]

Well, if you look at the image here: http://uanews.org/node/15715 it seems to me what you see is the hole (or "pit") that seems to be poked through the top of an underground void, with the sun shining on the floor sime distance below the lower edge of the pit's wall, with the shadow on what would be the floor of the void caused by the obstruction of the other side of the crater. Does anyone else see this, or is it just me? I'll admit to a bias: I'd love to hear of large voids (and many of them) under the martian surface; it'd be a possible environment where life could be found, and could also be useful to later exploration and colonization hopes (assuming the 'cielings' would be strong enough - but then there's always reinforcement).

Anyway...just my take.

[JESMKS]

Some of the lava tubes in Oregon contain ice that stays the year around. Possibly the lava tubes on Mars could also accumulate ice

[Michael Noonan]

I would be curious to know if there is a layer of soil preservation from the original event and whether that soil analysis contained micro glass sphericals.

I would assume something like a nickle iridium spherical, just out of curiosity.

I mean the Hawaiian volcano site not the Mars pit.

[Terry Gush]

I'm with thothicabob's take.

IF you consider the problem of calculating a minimum depth of the pits starting with these three premises,

1) We can see dust dunes at the bottom of Victoria crater where one of the rovers is currently looking for a recoverable point of entry, and we know dust deposition is a threat to the Mars rover's solar panels, we have pics of dust devils, so we know beyond doubt that dust deposition happens on the Martian surface. It couldn't be too difficult to approximate an average rate of dust deposition from the annual Martian dust storms in the general vicinity of these pits,

2) If, as is the case in Hawaii, the pit structures form in the latter stages of a period of volcanism,

and,

3) Martian volcanism ended about a billion years back (thank you for the recent Mars podcast AstronomyCast) and this provides a rough as guts age of the pits being equally acient,

THEN, there is adequate scope to conclude the pits would have to very deep indeed not to have been filled in and completely obscured by dust since their formation.

So, EITHER they are very very deep (possibly leading to an underground void as thothicabob speculates),

OR their formation is a much more recent event compared to the end of the Martian volcanic period and remotely possibly not related to that period.

The Mars Reconnaissance Orbiter which arrived in November 2006 is equipped the with SHARAD, the Shallow Subsurface Radar instrument which can penetrate ground to a range 7m to 1000m (http://en.wikipedia.org/wiki/Mars_Re...AD_.28radar.29).

Does anyone know if the MRO SHARAD instrument is going to/has/can collect data on these pits and there surrounding sub terrain?

Kind regards,
TG

[transreality]

there are impact craters on the slope, so formation is ancient.

[JESMKS]

There is also the possibility that the opening to the surface is the result of a roof collapse and the opening is much younger than the underlying lava tube

[Jerry]

there are impact craters on the slope, so formation is ancient.

That's camoufolage on the hatch. (We managed to capture an image while it was open, and now they don't dare close it