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banquo's_bumble_puppy
2005-Feb-04, 05:02 PM
Okay this has got me puzzled-

http://marsrovers.jpl.nasa.gov/gallery/all/1/f/366/1F160676950EFF42D9P1214R0M1.HTML

they dug a trench in the sand and yet the sand streak seems to be in the trench as well??? look for yourself

banquo's_bumble_puppy
2005-Feb-04, 05:04 PM
material must be fairly cohesive for the streak to have been preserved under the rover wheel

aurora
2005-Feb-04, 05:16 PM
Is that really a trench? Looks like a small berm. How did they pile the loose material up?

ToSeek
2005-Feb-04, 05:46 PM
Is that really a trench? Looks like a small berm. How did they pile the loose material up?

They drag the rover's wheel back and forth.

slinted
2005-Feb-04, 05:57 PM
I'm sure there are more frames of this to come, but here's 5 frames from the trenching operation from the left front haz camera:

http://www.lyle.org/~markoff/collections/oppsol366_fronthaz.gif

lyford
2005-Feb-04, 07:17 PM
Here (http://marsrovers.jpl.nasa.gov/gallery/all/1/n/366/1N160677102EFF42D9P1901R0M1.HTML) is a better view in the trench:

http://marsrovers.jpl.nasa.gov/gallery/all/1/n/366/1N160677102EFF42D9P1901R0M1-BR.JPG

While the material may go down to a little depth, I think the ripple "continuing" in the trench is mostly an optical illusion - our minds fill in the gap. If you look at the sides, there isn't any change in texture.

Let the PanCam decide!

ToSeek
2005-Feb-04, 07:32 PM
Is that really a trench? Looks like a small berm. How did they pile the loose material up?

They drag the rover's wheel back and forth.

My bad - as the time-lapse shows, they lock the other wheels and spin one wheel to dig a trench.

lyford
2005-Feb-04, 07:52 PM
My bad - as the time-lapse shows, they lock the other wheels and spin one wheel to dig a trench.

Don't fight fellas, you're both right! (http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040217a.html) :lol:

(From Opportunity's 17-Jan-2004 Press Release)

What Lies Beneath

The Mars Exploration Rover Opportunity dragged one of its wheels back and forth across the sandy soil at Meridiani Planum to create a hole (center) measuring approximately 50 centimeters (19.7 inches) long by 20 centimeters (7.9 inches) wide by 9 centimeters (3.5 inches) deep.
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040217a/09-rb-1-trench-B024R1_br.jpg

This animation shows a later lock, spin, trench and drag routine - 1.7 mb GIF. (http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040414a/Sol73B_Trench_Animation_br.gif)

MicroKid
2005-Feb-05, 12:35 AM
Nice trench. Very firm soil:

http://img.photobucket.com/albums/v376/MicroKid/1N160677102EFF42D9P1901R0M13d.jpg

twinstead
2005-Feb-05, 07:30 PM
While the material may go down to a little depth, I think the ripple "continuing" in the trench is mostly an optical illusion - our minds fill in the gap. If you look at the sides, there isn't any change in texture.


I was thinking the same thing. I also suspect it is an optical illusion more than anything.