- 220 KB
- 2.1 MB
course, the scenes
The reader will please forgive me for
hard on these visual points as people continue to believe that Titan's
seas are dry, largely through non recognition of the ubiquitous liquid
in the Huygens images.
In the upper scene, it was something
feet to the shore in view and the waves around a foot tall with the
a foot above sea level, hopefully not too dissimilar to Huygens. Some
can be seen drifting along. The waves build and break as whitecaps
the rising beach, different from where they strike a sudden obstacle
break into spray in Huygens's scene. On Titan, there appear to be
floating things bobbing up and down in the waves (also seen in the
images), but no seagulls flew by.
In the tide pool, there are some
reflections off of
rock face behind the puddle and a few bits of floating gunk, plus there
were some raindrops, all making the surface more evident. I couldn't
the slight, slow swells of Titan as there was too much gravity at this
particular tide pool. It being Earth daylight, no lamp lit up the
The camera was on a dry rock, and likewise there's no necessity to
Huygens had to be immersed in the nearby liquid to show the scene it
There's less signs of vegetation, but a leptocottus armatus* swam
The solid parts of my scenes don't
what Huygens landed on undulates and flexes gently in the waves or
were some hefty heat waves making it appear so. (Not impossible - after
all, Huygens was hot after it entered the atmosphere, and it had
Notwithstanding the differences, a
of wavering of the features under the motions of very shallow liquid is
obtained in both animations. The submerged foreground features are less
clear than the not submerged ones behind and there are some reflections
towards the far side.
Note: An animation of the MRI and HRI
is visually less interesting than the SLI. However, something happens
the window of the MRI 3 or 4 times, each time shrinking the bright blob
on the lower right. Hit by waves perhaps? And twice droplets of liquid
can be seen which drip off (or otherwise disappear). The HRI lens
appears to get hit by something once, much changing the view. If they
submerged, these events may be occurring on the insides of the windows
via leaks. (If Huygens is on dry ground, what is happening?)
In this final "Huygens anniversary
here are three shots of shallow liquid from above, simulating, albeit
a tiny scale, the sort of view angles of Huygens's HRI imager during
The triply processed images show that
is plainly there in the original color shots, it becomes less evident
the contrast is increased, and almost invisible if made monochrome.
the Huygens shots, we only have the latter. In the bottom right image,
the waterline is visible, but tracing its course, and recognizing
what it is without first suspecting liquid, might be tricky.
on the ACCELEROMETER DATA AT LANDING
of [un]stable data points immediately following the initial impact
- 8,870.3 s) may be due to a small bounce of the probe or to some
This is the sort of finding I was
of the gentle "creme brulee" landing.
I am beginning to view the landing
area (if not the
world) as a saturated bog of organic sludge that has built up by the
flows to virtually the surface level at many points, with the flow then
channeling mainly through deeper areas. (The Louisiana wetlands comes
mind.) Given the expectation of atmospheric haze particles drifting
to the surface from the upper atmosphere, such an organic sludge could
perhaps exist even if there was no life on Titan.
HASI ACC PZR X sensor registered a small precursor peak of a few meters
per second squared in amplitude. One possibility is that it may be due
to impact of the probe's foredome with an isolated protuberance such as
an "ice cobble"; resting on the surface."
This gentle deceleration that
"gradually" built up
zero just before the probe actually struck the ground may be due to the
foredome striking the very shallow liquid methane on the surface, whose
depth can thus be estimated (very, very approximately) as:
liquid = time of transit (initial small deceleration reading until
solid impact reading) * velocity
= .01 to .015 seconds * 4.60
= .046 to .069 meters or 4.6 to
6.9 cm - 2 or 3 inches.
course, with such
liquid, one spot might be twice as deep as another right next to it,
on the texture of the surface, so a precise result is perhaps somewhat
academic. The reading could perhaps also be explained by a cushion of
leaves just above ground level. Both leaves (not, I believe, ice
and liquid seem evident in the surface animations. However, either way,
one wouldn't really expect the force to taper off again as it does
the main impact.
In a possible "bounce" after the
negative G force of short duration is seen at one point, actually
than Titan's gravity, as if somehow, the surface had got a grip on
and wouldn't let it bounce up. This could be explained by something
the penetrometer from rising (seems unlikely), or general momentary
from liquid or saturated sludge as Huygens tried to lift out in a
(more likely). However, this bounce, and another major difference, was
measured by just one of two accelerometers (ACC PZR-X). The other
claimed there was no bounce at all.
(These differences should warn us
of individual instrument readings, like individual "face on Mars"
in an image, are not infallible. If either accelerometer had not been
the other would probably have been taken as being definitive. Of
I'm thinking of the SSP results, some of which are said to
rule out liquid, somewhat at odds with the GCMS surface liquid findings
as well as the liquid visible in the images - as plainly as contrast
monochrome images can show it. And (ahem) some of my own earlier
image feature interpretations. But I digress.)
The timing of almost three seconds
to stability of readings, as well as the gentleness of the forces, is
of a landing on a surface that was by no means solid (like sand with
or mud or clay), but rather something having some definite, if small,
aspect to it that rebounded and appeared to cause sideways motion as
A soil of marine 'sludge' could perhaps cause this result. An
experiment might be to take a "Huygens" equivalent and drop it with
force here onto various surfaces and see what would cause similar
including peat bogs and shallow swamps. The seeming surface undulations
over time visible in the animations were not detected by the
so either these were gentle in the extreme and hence the feeble
were hidden in random background noise, or perhaps they were "mirage"
waves caused by Huygens itself and not real motion. The instruments
sensitive enough to tentatively detect a gradual change in tilt of
of about 1/2 a degree over the 70 minutes of transmission and to
that Titan's radius may be 3Km greater than the published figure of
My comments on statements about the landing site,
taken from various news clippings [immediately after the landing].
it was not with a thud, or a splash, but a 'splat'. It landed in
'mud'. I think the biggest surprise is that we survived landing and
we lasted so long," said DISR team member Charles See. There wasn't
a glitch at impact. That landing was a lot friendlier than we had
on the accelerometer readings. This is not inconsistent with the very
liquid seen in the view from the ground. So splat yes, mud no. The
was cushioned by the belly hitting a few inches of liquid methane,
about the same time as the 12 cm accelerometer probe struck the stone
then sliced into the sand or gravel as elsewhere stated.
landing, material that appears to have accumulated on the camera lens
the final images suggests the weight of the 705 pound probe may have
it into the muddy surface."
It looks more like something was
in front of the lens
and has partly moved aside in the later images.