In M07-05177
we have another crater floor pond, again full of floating
objects like the ones we saw in M04-00604; but this time
there are at least two important differences. For one, the
sunlight is glinting off the surface of the liquid (the
other was in shade) and illuminating the floaters
far more effectively. For another, the resolution in this
image is finer. Here you can see much more clearly that
each floater does indeed consist of a dark nucleus with a
paler or more transparent outer portion. Remember what I
predicted with M04-00604 near Darwin? Well...
You wouldn't expect this at such a large scale, but the liquid presents the
appearance of having very strong surface tension -- both through the smoothness
of its outline and in the way the floaters distribute themselves. On Mars under
a 38% earth-normal gravity the surface tension of any liquid would have less
weight to fight against, certainly, so it makes sense that water WOULD tend to
hold a stronger meniscus than it does here and would therefore appear quite
jelly-like. Again, along with this I'm assuming it has to be a highly
concentrated salt water of some sort to sustain liquidity at a wide enough
temperature range that we'd be able to see it that way "so often."
At
that time I thought maybe the fuzzy perimeters consisted of
branches unresolvable at that scale. In this version we can
now, just barely, see that there ARE branches of some sort
issuing from those nuclei. The light portions also show some
radial granularity here that certainly appears to transition
these structures into finer networks.
The scale for this shot is 2.76 meters per pixel, compared
to the 4.15 meters per pixel in M04-00604. That plus the
more favorable lighting makes all the difference.
The context photo and reduced srip at left have false color.
The original-scale images above are contrast-enhanced.
The outer diameters of these floaters average around 60 meters (200 ft). The
opposite extreme seems to cut off at around 6 to 8 meters. Note that the size
distribution appears bimodal in that the floaters seem to favor the
endpoints of that range. There are some of intermediate size, to be sure, but
not nearly as many as you'd expect from a random process. This is a further
circumstantial argument in favor of a biological system.
