Thursday, March 17, 2005

More on Enceladean Atmosphere discovery

I posted this on a news group and thought it was nice enough to post here.
When I first saw the subject of this release, I thought it refered to another instrument, which I will not name here but I can tell you it wasn't us (ISS). Let's just say that it can't be sputtering or some other process that would dislodge water ice from the surface.
I think we also need to think in terms of sources. Personally, I see nothing on the surface that screams volcano or caldera (maybe...). I see nothing but craters in terms of point sources. However, both VIMS and ISS saw differences in grain size at the fracture zones, both in the bedice and in flat deposits at the base of scarps (not the same as the talis). In the details I am of course using the ISS images released yesterday. There is one fracture which appears fairly young since it seems to not have been smoothed yet by the effects of micrometeorites. In global images there appears to be a dark "deposit" surrounding that fracture. So, I'm thinking, what if the fractures are the source of the volcanism. They open up, expell gases (or water/ammonia mist) from the interior, close back up. The gases freeze quickly, and either escape Enceladus to become the E-ring, become part of Enceladus' atmosphere (then later the E-ring), or fall back on Enceladus whiter than freshly fallen snow.
I like to think of Enceladus as the world of contradictions. It's got both very young (< 10-100 Ma) surfaces, and comparatively very old surfaces (500-1000 Ma). It seem that ammonia would be needed to depress the melting point enough to cause this level of activity, but no ammonia has been seen on the surface (though this can be explained away easily due to the UV effects on exposed ammonia). Some other inconsistencies maybe released in the coming days.
Well, I better start gearing to get a nice seat for the second Cassini Session. I will try to post a message regarding info from these sessions later today here.

Cassini MAG team finds faint atmosphere at Enceladus

The MAG team released a notice yesterday on the potential discovery of an atmosphere around Enceladus. With Enceladus being a potential location for active volcanism, finding an atmosphere could be an important find for confirming geologic activity.

Wednesday, March 16, 2005

Enceladus Images

Enceladus image

A number of images were released today showing intreguing features on Enceladus that are very reminicent of features seen on Ganymede, Europa, and Miranda.

Tuesday, March 15, 2005

LPSC Day 2: The Beginning

So far all quiet on the western front. Most of the first day's sessions cover Mars, as do today's sessions, so there really isn't much to report. I haven't seen too many Cassini people here yet, and those I have seen, I see everyday anyway at the U of A, so that doesn't really count now does it? Well, I'm off for some grub then to a session on the OMEGA instrument on Mars Express. I know my boss has a talk at the Martian Impacts session, but I am just not interested in Martian ALL (sorry Alfred).

Monday, March 14, 2005


Just to let everyone know that I am LPSC now, so if you are here and want to talk to me, I am here and will to talk (unless 24 is on and then I will have nothing to do with you). Anyways, for those not in Houston for this conference, this will mean that my updates will come few and far between since my internet connection is limited to 15 minute sessions in the basement WIFI zone (or is there one here on the first floor... I should try that...). When I do post, it will be mostly notes on what's going on at the conference and outer satellite news made here. Those will mostly come later.

In term of other news, the Enceladus press releases should be out by now, not sure yet...