[X] My Assistant

[centsworth_II]

I wouldn't mind sending Opportunity to one of those promontories.

Let's just wait 'til after the asteroid hits!

[dilo]

The same Panoramic view but now, I have added the images taken on Sol 1391 with the R0 Navcam.
Again, all the images with "Dust Removal".

jvandriel, your mosaic is superb!
I retouched some residual dust artifact and added artificial sky in this version:

This is the Polar version:


(Happy new year to all UMSF members, I will be back on Jan,05)

[Shaka]

It could hurt at Cape Verde in terms of solar exposure. There should be a significant shadow southwest of the cape in the morning, which could only be avoided by working near the tip of the cape. Also, the tilt of the solar arrays will be more away from the sun (southerly) during the winter. Whether these deficiencies are dangerous would have to be calculated. Personally, I favor the nearside of Cabo Frio - for these reasons - as a winter study area. We could work our way gradually SE along its length, examining progressively deeper strata.

[dburt]

Interesting description there of Cape Verde: I wonder how close they'd dare get.

Thanks for noting those new super-res images. I enjoyed the comment regarding Cape St. Mary: "Like the Cape St. Vincent images, these Pancam super-resolution images have allowed scientists to discern that the rocks at Victoria Crater once represented a large dune field that migrated across this region." As noted in some posts last June, based on the initial imagery, Cape St. Mary seems to have some very nice exposures of what looks like "festoon-type" or trough or current cross bedding in the lower right hand side of the cliff. Everyone who commented on the images (3 people) agreed with this assessment at the time. You can now see them even better in the super-res photo (or even in the lower-res, "medium image"). How typical are such "festoons" of eolian dune fields, inasmuch as they were earlier held (uniquely - no corresponding channels or braided stream patterns, etc.) to indicated water flowing across the former flat eroded top of the dune field? Also, as always, why do the bulk of the cross-beds not look like at all like typical dune forms (that is, why do they mostly occur at very shallow angles, and at all scales intermixed)? To me they just scream "whoosh!" (of course, I may be predjudiced ).

In this regard, the Will Smith film "Independence Day" was on cable again last night (a frequent occurrence). I am always struck when watching that film by the weird but wonderful depiction of "alien surge" as the preferred method for destroying cities (radial, groundhugging, turbulent, fiery surge - scooping up cars and frying people - that mysteriously lacks any corresponding central explosion or expression of dissipation with distance). Wouldn't it have been simpler for the aliens to lob asteroids? Oh well. Sort of a nice depiction of base surge, anyway.

-- HDP Don

[djellison]

why do the bulk of the cross-beds not look like at all like typical dune forms

Typical dune forms where? Would the differences in pressure and gravity not render comparatively analysis a little dodgy?

Doug

[hendric]

Wouldn't it have been simpler for the aliens to lob asteroids?

"Babylon 5: The Long, Twilight Struggle (#2.20)" (1995)
Londo Mollari: Refa, any force attempting to invade Narn would be up to its neck in blood--its own!
Lord Refa: We have no intention of invading Narn. Flattening it, yes--but invading it? We will be using mass drivers. By the time we are done their cities will be in ruins, we can move in at our leisure!
Londo Mollari: Mass drivers? They have been outlawed by every civilized planet!
Lord Refa: These are uncivilized times.
Londo Mollari: We have treaties!
Lord Refa: Ink on a page!

There is a great scene of cruisers launching asteroids onto the planet, and they deal with the aftermath later in the series, with Narn plunged into an "asteroid winter".

[Doc]

I have re-examined the area around Cape Verde to see how close the rover can actually approach the thing.

The promontory is roughly 23m away (from sol 1333 position).

I have not taken into account the shadow (of the promontory) that will fall on the rover panels. Just the slope factor.

Please dont hesitate to refine my observations

{See attachment.}

[Shaka]

I would have to question the utility of approaching the capes, if we cannot get close enough to the bedrock exposures to examine them with the IDD instruments. Whether kept away by slope or shadows, Oppy could gather only minimal new information from 5 meters away. We should find places where we can reach the exposed cliff. Maybe you should repeat your diagnosis for Cabo Frio, Doc.

[djellison]

If they can close from 15m to 5m - that's quite a lot more resolution on the Xbedding.

If it was worth doing super resolution imaging to get a few 10's percent increase in resolution - it's worth driving a little closer to get a double in resolution.

But - not so close that it'll impact power and comms.

Doug

[Stu]

Lovely layers here Oppy, thanks...!

[dburt]

Typical dune forms where? Would the differences in pressure and gravity not render comparatively analysis a little dodgy?

Doug

Doug - Agree in principle, but dunes on Mars are hardly unknowns - they've been imaged from orbit since long before the rovers landed. Clearly, Martian dunes can be quite large and the same morphological classification has been used (e.g., barchan, star) as for terrestrial dunes. Also, the interpretation that the Victoria cliff exposures were typical dune forms was from the NASA web report, not me. (I'm with you.) I questioned it, based on my own limited experience (limited to intense examination of the same Arizona - Utah eolian sandstone exposures to which the martian exposures have most often been compared). IMHO, they look remarkably unlike the martian exposures, except for being cross-bedded. The martian details are different, and very much messier (e.g., cross-bedded at every possible scale, and at a variety of angles, mostly low). Compare the images with those in any geology textbook and reach your own conclusions, however.

A variety of flow types (e.g, wind, water, surge) can result in cross-bedding. Distinguishing among them can be challenging, especially given that terrestrial examples of impact surge deposits are lacking. I fully agree with you, therefore, that such factors "render comparative analysis a little dodgy".

BTW, the same cautionary principle applies to high silica or vesicular rocks. On Earth, such rocks typically result from volcanism, but who's to say that on Mars they might not represent impact-related hydrothermal activity or bubbly impact melts? Oh well, I can safely state - not bubby champagne! Happy New Year.

-- HDP Don

[DFinfrock]

In this regard, the Will Smith film "Independence Day" was on cable again last night ...

-- HDP Don

What bothers me about that film is the final scene, as the radioactive pieces of the exploded alien mothership streak into the atmosphere, providing Will Smith's promised fireworks for Independence Day. They enter the atmosphere and streak across the sky in parallel. Shouldn't they appear more like a meteor shower, radiating from a central radiant point in the sky?

David

[Guest_Oersted_*]

True, that was not correctly done, the rest of the movie was much more realistic...

[hendric]

Really? I don't see it that way. Think of a shower head, with your head as earth and the droplets as pieces of the ship. The mothership was presumably in orbit around Earth, so just barely have the water hitting the top of your head. All the pieces would essentially look parallel as they entered the atmosphere.

Meteor showers are from particles in their own orbit around the Sun, so they don't go around earth. You can simulate that by placing your head directly in middle of the stream. In this case, the droplets would zing by on either side of your head, with the shower head appearing as the "radiant".

[ilbasso]

...and if the ship were over the horizon behind you, all the streaks would be following the path described.

Perhaps this discussion belongs in its own thread. The question is whether the alien mothership is considered "unmanned" since the inhabitants weren't human...should we change this forum to "Uncrewed Spaceflight"?