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Galileo images and mosaics of Europa
Ian R
post Feb 3 2015, 12:25 PM
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A mighty congratulations are in order, Bjorn! The culmination of a two-year project of this magnitude is something to be celebrated, and I hope you get the recognition and plaudits that this achievement so richly deserves.

Ian.


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algorimancer
post Feb 3 2015, 03:06 PM
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The full resolution version is pretty amazing -- someday it would be really nice to have a Google Earth version, like we have for Mars. A lot of details pop-out which I hadn't dwelled on previously. There are a scattering of large berg-like features, almost like boulders lying partially submerged in the surface; if we posit the thin ice shell model, these may arguably be spots where the shell has doubled-up (stacked one layer on another). I'm out of touch with Europa research, but it seems like someone ought to have studied these in depth, perhaps modeled and measured their displacement of the surrounding surface, perhaps established whether they are in hydrostatic equilibrium. Neat stuff.
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machi
post Feb 3 2015, 11:55 PM
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True masterpiece Bjorn!
It's really pity that we haven't good topography data. It would be really tempting to combine your excellent map with some nice topography data.
Hopefully it will be possible some 20 years later with data from new Jupiter system missions.


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tedstryk
post Feb 6 2015, 12:36 AM
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Beautiful work, Bjorn! That may be the smoothest looking global rendering of anything from Galileo data I have ever seen.


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Bjorn Jonsson
post Feb 18 2015, 08:55 PM
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My brand-new 20000 x 10000 pixel map of Europa can now be seen here: http://www.planetary.org/blogs/guest-blogs...ing-europa.html

This is by far the biggest image processing project I have ever undertaken in terms of time and number of images (but not complexity). I now have a big directory tree associated with this image processing project; it consists of about 50 GB in 2500 files and 135 folders (!). A lot of it is temporary stuff though that can be deleted.
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ectoterrestrial
post Feb 19 2015, 07:59 PM
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QUOTE (Bjorn Jonsson @ Feb 18 2015, 01:55 PM) *
My brand-new 20000 x 10000 pixel map of Europa can now be seen here: http://www.planetary.org/blogs/guest-blogs...ing-europa.html

This is by far the biggest image processing project I have ever undertaken in terms of time and number of images (but not complexity). I now have a big directory tree associated with this image processing project; it consists of about 50 GB in 2500 files and 135 folders (!). A lot of it is temporary stuff though that can be deleted.


Wow, Bjorn! Thank you for this.

What is your impression of the red-yellow hemispheric dichotomy? Could it be an observational bias, or due to reflected Jovian light?


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Bjorn Jonsson
post Feb 20 2015, 03:53 PM
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QUOTE (ectoterrestrial @ Feb 19 2015, 07:59 PM) *
Wow, Bjorn! Thank you for this. What is your impression of the red-yellow hemispheric dichotomy? Could it be an observational bias, or due to reflected Jovian light?


It's neither of these. The color/brightness difference is real, Europa's leading hemisphere is brighter than the trailing hemisphere.

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nprev
post Feb 20 2015, 06:59 PM
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Please correct me if I'm wrong, but I thought that the hemispheric color asymmetry was thought to be due to the leading hemisphere being subjected to the brunt of Jupiter's radiation belt as the moon orbits thus causing decomposition of volcanic effluent deposits from Io (which aren't subjected to that on the trailing hemisphere & therefore persist.)


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ectoterrestrial
post Feb 20 2015, 08:25 PM
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QUOTE (nprev @ Feb 20 2015, 11:59 AM) *
Please correct me if I'm wrong, but I thought that the hemispheric color asymmetry was thought to be due to the leading hemisphere being subjected to the brunt of Jupiter's radiation belt as the moon orbits thus causing decomposition of volcanic effluent deposits from Io (which aren't subjected to that on the trailing hemisphere & therefore persist.)


Its slightly more complicated than that.

The Jovian magnetosphere rotates faster than Europa's orbital velocity at Europa's orbital radius.

As a result, Europa is getting bombarded by charged particles on it's orbital trailing hemisphere. It is also picking up uncharged particles and dust from it's orbital motion on the leading hemisphere.

One obvious result of this is the hemispheric color/albedo contrast.

I knew that the orbital trailing hemisphere showed signs of enhanced "weathering" but I did not realize the magnitude of the contrast. Bjorn's processing really brings this maps alive for me.



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