AstroFest

I go to a lot of conferences. Some are good, some are bad, and most are just, well, a generic conference. In addition to the science content presented, I tend to judge conferences by three other criteria: Is it pleasant (are the hotel and conference center places I like being and within walking distance of things like good coffee), are we able to eat in a reasonable way (enough time and options), and is networking possible (are there people I want to talk to and is their time to actually talk to them)? This conference is a winner on all counts.

[warning – this was written over a period of a couple days]

Day 1, afternoon: I’m sitting in review talk on Mars polar regions that is presenting excellent science at just the right level for an audience of experts who are experts in things other than Mars. Given by Adrian Brown (http://abrown.seti.org/), the talk’s jargon is minimal or explained, but the content level is beautifully rich. Lunch was excellent and brought to us so we could focus on networking, and the facilities are such that we can spread out and talk in groups of whatever size we want. We are in a middle of nowhere town, but there is everything we need within walking. My hat is off to the Three Rivers Foundation and SAO for providing such an excellent location and infrastructure. It isn’t posh – everything is modest and home grown. But it is what is needed in every way. They even have extension cords and tables in all the rooms so we can pound on our keyboards while watching speakers.

Adrian is showing an image of the Southern Polar Layered Deposits on Mars that looks like some amazing textile. The layers, when seen in HiRise’s 1m-scale resolution, are like color hills formed in gentle rows. When we first downloaded low res images of the features with MOC a (decade?) ago, we assumed these were discrete layers of ice deposit. Now, with HiRise, planetary scientists are having to re-explain the geology of Mars. (http://hirise.lpl.arizona.edu/PSP_003341_0935)(http://hirise.lpl.arizona.edu/PSP_001636_2760)

The Martian “spiders” (also Southern Polar Region) are also deeply confusing. Seen in HiRise, we can see these features as ejecta from some sort of jet – perhaps melting dust-ice that forms high pressure pockets of material that eventually burst through the layers of clear ice above, leaving these dust pushed ejecta patterns on the surface. (http://hirise.lpl.arizona.edu/PSP_002652_0930)

Day 1, late afternoon: New speaker, new Martian features being discussed. Jen Heldmann (http://128.102.195.51/people/bios/space/heldmann.html) is looking at the comparative geology between the Canadian High Artic (and its saline springs and gullies) and the Martian gullies. The speaker is a researcher working to test if high-saline water could exist on Mars and pop out the surface occasionally. We see this on Earth, where salt-water flows in the Arctic in glacial regions even when the air temperature is 10s of degrees below freezing. (http://hirise.lpl.arizona.edu/PSP_003498_1090)

The Martian gullies are found between 30 and 75 degrees latitude (decreasing in number as latitude increases) and primarily at average latitudes (not in deep valleys and at the tops of mountains/volcanoes). They are also found on all slope orientations (slope toward and away from the Sun) and stable slopes (with big words: the angle is beneath the angle of repose, above which stuff tumbles). The gullies also typically come out 200 m below the surface and fall in areas that are ice-poor.

Through mathematical modeling, she demonstrated that liquid CO2 can’t exist in aquifer’s where it’s needed, but liquid water can. As that water gets near the surface, it freezes, creating a plug that can build up pressures of water is trying to expand/flow. The problem is, not all the gully locations look like they should have liquid water near them. If you add salt, or change the composition of the material above the liquid. Before today, I’ve heard people mostly put forward salt, but salt hasn’t been found near the gullies. Changing the materials above the sub-surface water, however, can allow gullies to occur in many different locations.

So, she has put forward a way to get water to the surface of Mars, but water can’t exist on the surface because water “Boils” off very very quickly. This raises the question: Can water exist just long enough to carve gullies? Using energy transfer models she studies how far the water gets before evaporating. Using a computer models she found salt water (salinity=0.02 flow rate 50 m^3/s) creates a gully with depth=0.5m that goes 10s of km. Pure water on the other hand (rate 30m/s, depth 0.3m) goes 0.5 km – this matches observations. This matches!

But now must explain why dry landslides don’t work. Sinuous, incises, and V-shaped channels don’t form from this. What about melting snowfall? That doesn’t explain why gullies only occur at 200m down from alcoves and not all over an area.
Now, I have to admit, the whole time this charismatic speaker was telling her story, I was thinking about the press release from HiRise a few weeks ago about how gullies *aren’t* formed by water. I was all primed to ask her about that. Then she went and explained they are finding three different types of gullies, and the other two are subsurface liquid or debris flow (that’s what the HiRise press release talked about). She mentioned some people (press officers, in some cases) are trying to say that because their gullies aren’t water driven, no gully is water driven, but models can’t prove that thesis. With her separate models for each of the three types of gullies, she did show that different processes can create different geological features.

Day 1, Evening: We drove 30 minutes out to the Comanche Springs Observatory, and I have to say I’m very impressed. They have build facilities with a classroom, domes, pads, well groomed walkways, enough bathrooms, and immaculate landscaping. The place was designed for doing EPO, rather than as a place for amateurs to just go do personal observations in a group environment. This change in mission leads to a lot more care in design. There is crowd control designed into the flow of the paths, that naturally guides people from field,  to class, to dome, to roll off, to field. The robotic telescopes are off in the distance, but still easily gotten to for those wanting to explore. We did a roughly 30-minute daylight tour and then headed for dinner (http://www.3rf.org/Sciences/CSAC/ComancheSprings.htm)

Our not so little group invaded a local steak place and ate well and drank well and that’s all I say for fear of making you too jealous 🙂

And after dinner we did some star gazing. Some folks lasted all the way to 3am. I didn’t 🙂 But, I climbed a ladder to see the Ring through a 30-inch dob (very good image, very scary ladder), looked at Andromeda through a binocular telescope, and saw a few other things through a few other large by not-unusual telescopes. I really really wish I’d brought my 35mm camera to do some photography.

Day 2, morning: I talked again. This time on standard stars. I’ll throw up a link to the site I’m creating to support my talk. Enough said.

Day 2, afternoon: Pretty Image making 101. Hubble Heritage Team Member Jayanne English gave a talk and hand-on workshop on the aesthetics and techniques required to create pretty images. That will also get its own entry later. Jim Peterson also gave an excellent talk on the history of Apache Point Observatory. I have to admit, I’m having an allergic reaction to something, and am a but fuzzy.

Day 2, evening: More steak, More stars, 1 Snake (someone else saw it though).

Day 3, morning: I’m getting ready to leave and being rude and typing while Sarah Maddison talks about different aspects of the Swinburne Astronomy Online program and her research in planetary formation and dynamics.

I’m  going to post this without images (but with links to images). I’ll add things in as I get a chance.

Side note: I think the ratio of male to female speakers is about 50-50. (8 talks by women, 5 by men, but three of the women, including me, gave 2 talks each). Compare that to this.

3 Comments

  1. Ahiy October 14, 2007 at 3:35 pm #

    “enough bathrooms”??

  2. Helio Huet October 14, 2007 at 3:39 pm #

    Nice report of a potent astrofest thanks largely to the great speakers. There is something satisfying in hearing of the logic in likely gully washers on Mars in a presentation to Texans.

    I sure hope such an event makes it to San Antonio, by gully (or otherwise).

  3. Pete Kalajian October 16, 2007 at 8:52 am #

    Pamela,

    I emailed you but your email was sent back as undeliverable.

    I’m an SAO student (we’ve been emailing) and doing a deep field project. I’ve gathered, calibrated and summed my 44 5min images of Abell 2666. Now exactly what should I be doing?

    Pete Kalajian

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