The Sounds Of Venus? Options

[Guest_BruceMoomaw_*]

In its latest print issue, the Planetary Society reported the following, in connection with GROZA (the attempted thunder-detecting microphone on Veneras 13 and 14):

"The Planetary Society recently contacted GROZA's principal investigator Leonid Ksanformaliti, an old friend of the society from the Space Research Institute in Moscow, and asked if these data had ever been converted to sound. They had not. At the Society's request, he generously pulled out the old data and has begun the process of converting the data to sound. These Venusian sounds will soon appear on the Planetary Society's website."

Well, Jeffrey Bell -- AKA Mr. Sunshine -- now reports to me:

"Argh! Unpleasant memory blast from former life! Resist powerful urge to smash expensive flat monitor!

"I had some dealings with Comrade Ksanfomaliti back at the time of the PHOBOS fiasco in 1988. I wouldn't trust him to clean my air conditioner. He was one of those all-purpose scientists who made an instrument for every mission, always a different instrument in a different field, and always a disaster. He seemed to have some powerful political influence that kept him in the program. Of course the PS
would latch onto this guy, with their unerring nose for incompetence."
_____________________________________

Well, that's OK -- if no interesting Venusian sounds turn up on those tapes,
the Russians can always fake some. (After all, their "scientific space
program" now consists entirely of ways to continue sponging off NASA's Space
Station budget.) Be on the lookout for Venusian "thunderclaps" that sound
suspiciously like someone shaking a large sheet of tin.

[edstrick]

We do *NOT* know how well the Europa ice-crust is decoupled from the underlying rocky crust. Two things that have been massively ignored by press coverage of Europa are as follows:

1.) The geological activity patterns imply a thickening of the crust and declining activity patterns in each area. Thin-ice-pack breakup and rifting, followed by narrow cracking and/or hot-spot formation.

2.) Post Voyager models suggested that tidal heating in Europa may be inadequate to keep a steady state ocean liquid under a crust, but there may be cyclic heating and activity. The crust largely freezes, tidal energy loss is low, and the orbit builds up eccentricity under pumping from Io and Ganymede. That pushes up tidal heating rates till the crust starts to soften and you get runaway heating, massive melting, an outburst of activity, and the orbit rapidly circularizes, shutting off the heating and starting the next cycle as the crust freezes.

I think the geology is entirely consistent with such models. The one thing from Galileo that pretty much proves the crust isn't frozen down to rock is the magnetic field data that shows there's a conductive, probably brine layer, in the near-subsurface. Probably the crust concentrates salts and acids as it freezes till it can't freeze any deeper.

There's probably a lot of this in the technical planetary geology literature in the last decade that's totally below the horizon of press-release driven reporting which is most everything we see with few exceptions, like Bruce Moomaw's reporting.

[Guest_Richard Trigaux_*]

I think the geology is entirely consistent with such models.  The one thing from Galileo that pretty much proves the crust isn't frozen down to rock is the magnetic field data that shows there's a conductive, probably brine layer, in the near-subsurface.  Probably the crust concentrates salts and acids as it freezes till it can't freeze any deeper.

As a matter of facts when salty water freezes, it concentrate salt. And thus, the freezing point gets lower. So that an equilibrium is reached with a certain salt concentration.

But to have a cyclical activity, in your model, needs to have the water completelly frozen.

Perhaps Ganymede is more salty than Europe.

My idea about Europe is that the activity is rather due to accumulation of volcanic gasses from the rocky core. The gas dissolves in the water, until enough concentration is reached, and then the limnic eruption breaks the ice crust, lefting the blocks chaos which are observed in many places.

You speak of the decoupling of the ice crust from the rocky core. Two extreme cases are possible:
-The water is completelly frozen, we have an ice shield allowing eventual ice mountains to form
-there is a completely free water layer, and ice mountains cannot form

intermediary cases would be:

-the ice layer is free, but can be occasionally blocked by the summit of some rock mountains. In such case, the whole ice raft could break
-The ice layer is not free, but a thin water layer allows it to flow like a glacier.

The point of Decepticon was to hear the creaking of the ice crust, thinking that it floats on liquid water. To hear earthquakes in the underliying rock layer is another story, especially if there is a liquid layer. This is not impossible, this situation occurs on Earth, where seismic waves can travel through the liquid core, or through magma chambers. But I never heard of seismology through the ocean, frozen or not. There is a huge difference of density between water and rock, which makes the coupling low.