I’m as cool as Titan is Cold.

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Okay, this is blog post number two, updating on my work over the last couple weeks. Today’s date is October 13th.

First things first, for the non Neishlings out there, I’ve been added to Catherine Neish’s
tumblr_o0g3k4jtti1s02vreo2_500(my advisor) website as one of Master of Science students. I’ve been added to the departments website as well. I guess that makes me pretty cool. Or maybe not. The image they posted of me looks like I have some sort of growth under my left eye, but such is life I suppose.

Titan

More seriously, on to my work. I’ve spent a bit more time with the software ISIS. Catherine, Alyssa and I did another run through of how to use ISIS. I’d already done this with Catherine, but I had found that there were several minor details I had forgotten. I’m getting more familiar with how to use it, and more specifically how to find images. It helps that that’s exactly what we did.

We pulled a few sample images . Unfortunately, when I exported these images I didn’t realize the jpg was the resolution of the current view. i.e. I can’t zoom in to discuss these. We pulled 2 images, and processed one of them relative to their spatial coordinates (North is up, south is down, etc.). That one is the bottom left. The two images were the same region, but one was an older, less clear image.

 

 

I’m talking about the Cat Scratches on Titan. I’ve gone ahead and just added an image from google for reference. At first they baffled scientists, but, without getting into too much detail, we later discovered them to be giant sand dunes making up the Shangri-La Sand Sea. The dunes are made of grains of hydrocarbons from the atmosphere. In fact, we are still baffled at how such small grains could settle on the surface of Titan, because they should be so small that they stay suspended in the air.

titan_dunes_hires_900
A view of the cat scratches on Titan.

 

I’ve spent some more time browsing the Radar data set a bit more to try and review it on my own. I’m trying to get a more intuitive feel for the software and a better understanding of how to sort the Radar Data (i.e. time-stamp, location, etc.). I went into the Cassini archive data set to try and find all the images that are likely near Minerva Crater. I used the archive because I still don’t understand the difference between each data option. I know we want BIDR data, with beginning label of ‘BIBQ.’ I still don’t understand what it means. I’ll get around to looking it up, but for this I tried to find data that matched what we found together. The next part of the label goes up to ‘I’, representing the highest resolution. However,  lower resolution is all there is in some instances. We saw a piece of the crater in the above images which were around 24N and 0N. So I tried to find images that were located around 30 N to 10 S.

The example I present here is BIBQI26N009_D111_T023S01_V02, at 26N and 9W. Before I get into the image itself, I want to detail the process. Using ISIS, I convert the IMG files to CUB files for viewing. I was very confused about the significance of the LBL file. It wouldn’t work with the LBL file being used in the conversion window (left). Except this doesn’t work, so I tried to run it using the IMG file in the FROM and IMAGE to CUB. I thought maybe it would reference the LBL file, so I ran the conversion with the LBL in the directory and not in it. The result (right) was the same. I am not sure that it’s important in the conversion.

 

Maybe it’s needed for projections (like the one we did above) and mosaics. I’m hoping to get a better feel for this because the next step is going to be to mosaic and relate multiple images together to get a full picture of Minerva Crater. Tying into that, being able to do a mass conversion is something I’d like to be able to do. I’ve dabbled a little with it. I assumed it was a terminal function more than a ISIS function, but I haven’t been able to figure it out just yet. I may not worry about this because I don’t want to spend too much of my time trying to learn something I don’t really need for my project (which isn’t using that much data).

Moving on, the image is shown below, zoomed in on one region at random. I said above it’s near the equator (26N). That’s evident by the sand dunes, which don’t exist above 30N (I think). We may want to discuss this more in the Neish Lab meeting.

 

bibqi33n028_d120_t025s01_v02

 

Lastly, I’ve spent some time gathering papers (mostly using Zibi Turtle’s references) for grad seminar. Of course, this will prove helpful for my Titan work too. Over the next few weeks I’ll offer a literature review for the class and I’ll discuss it here.

This concludes Neish Lab work.

Europa

There is more to tell though. The Division for Planetary Sciences (DPS) meeting is next week. I won’t be there, but Britney will be presenting for me. I mentioned last time that I’ve been continuing the work I did at LPSC 2016. I am trying to relate the icebergs to the features that were there when they formed. The hypothesis is that ridges are stronger material so the more area they consume the more icebergs (the black chunks of regolith) left over. My approach is a statistical one, trying to correlate the areas of each component.

chaos
Galileo Images (left), with chaos region (grey) and icebergs (black) mapped in the center. The right is a paleo-map of the ridges (blue), bands (red), plains (green) that we suspect existed in this region. (Hedgepeth & Schmidt DPS 2016) The image is lower resolution to prevent plagiarism.

 

Results support my previous findings: Ridges do correlate with more icebergs. The correlation has dropped. I started with 6 chaos regions (all near the mitten, at the top of the figure). That gave~90% correlation. Going to 20 in the Mitten region gave ~50%, but with a low probability it was by chance. With Conamara (middle row), the correlation went to ~45%. With Thera Macula (bottom), it drops much lower, and the probability that it is by chance is very high. This is to be expected. Thera is unique because it’s suspected to still be active (Schmidt et al., 2011). The fact that it is a depression suggests that the subsurface is still liquid (so it hasn’t frozen to create a bulge like on the Mitten). Conamara is suspected to possibly be active as well. However, that is not required for the correlation to hold. If you’d like to know more, you can contact me.

Other News

In other news, we’ve begun grading the essays on ‘Life on Mars’ for the class I am TAing. I’m surprised at how excited I am for it. Hopefully the kids won’t make me hate it too much. It helps that I helped create the outline, so I’ve got a good feel for the whole question. Yay learning.

Also, my birthday is next Tuesday. That’s exciting.

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One Reply to “I’m as cool as Titan is Cold.”

  1. Hi Josh,

    A few comments:

    1. You can use ‘isis2std’ to turn .cub files into .png files. Then you can see the full resolution image in a ‘regular’ image viewing software (Preview, Photoshop, etc.).
    2. Barnes et al. (2015) addressed the question of how sand is formed on Titan. It’s an interesting read! (https://planetary-science.springeropen.com/articles/10.1186/s13535-015-0004-y)
    3. Running a bunch of commands in sequence is a really useful trick, even if you’re only going to be processing a handful of images. We can chat about shell scripting at another time, if you want to set up a meeting.

    Best, Catherine

    Liked by 1 person

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