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J. W. Daniels, MSc

One of Dr. Neish's new "friends."

Hello, World!

My new blog is up and ready to go….  I just need to get it linked to “Neish & friends”!

*update*  It’s been linked!  https://planetneish.com/research.html

😀

 

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Burning Bright

Image result for star guardian quotes

After nearly two decades of performing admirably, the Cassini spacecraft, nearly out of fuel, made one last service to Science by plunging into Saturn’s atmosphere sending its final stream of data back to Earth before burning up and thereby becoming a part of the planet it spent so many years getting to know.

Cassini officially burnt up yesterday, and for me such an act brought up this emotional scene from Haifuri — I imagine the great myriad of people who gave a fair share of their respective lives to the craft and its mission felt, more or less, like this:

The data Cassini collected over ~15 years about Saturn has doubtless been indefinitely valuable for the research of so many scientists and researchers.  Even among my own office-mates, Cassini data has proved vital to respective thesis work:

>Alyssa’s work on Titan:  https://alyssascience.wordpress.com/.

>Josh’s work on Titan:  https://jjoshh.wordpress.com/.

This is the ultimate legacy of Cassini:  Shedding light on the Saturnian system for scientists and researchers for decades to come.  Before Cassini, nobody knew what Titan’s surface looked like nor what its environment was like.  Before Cassini, nobody knew how dynamic Enceladus was (particularly its south pole).  Before Cassini, detailed imagery — and eventually maps — of Saturn and its moons were largely the stuff of dreams.  In many ways, Cassini was the Hubble of Saturn.

Image result for cassini photosImage result for cassini photosRelated imageImage result for cassini photosImage result for cassini photosRelated imageRelated imageImage result for cassini photos

The above is just a couple snowflakes on the tip of the iceberg that is the entirety of the Cassini data and imagery collected during its mission, a mere couple minutes’ browsing through Google Images selecting some highlights.

Twenty years ago now, Cassini took off from Earth.  I was only eight years old at the time.  While Cassini may no longer be with us, thankfully many other probes and rovers are; of course, Science is a never-ending quest for knowledge and as such ever more space missions are being planned and carried out by space agencies worldwide.

The famous Dylan Thomas poem about growing old and dying has been passed about a lot the past couple days concerning the craft and its illustrious life, but for me, because I sometimes play League of Legends, it seemed fitting of a Star Guardian who is meant to shine bright yet fated to perish even more-so.  In the end, I think both analogies are equally fitting….

Speaking of awesome planetary missions that have ended, I still have some MESSENGER imagery to work with and some craters to finish up cataloging for my own thesis project.  I’ll definitely have an update once it’s all done!

 

Aat Laaaaaaassst!!

After a month of failure to get Isis3 to properly render the MDIS-NAC files I downloaded from the MODE, success has, ultimately, been mine.  Ailey crater, which sorely needed these high-resolution images because of a pesky shadow in the MDIS Global Mosaic that occluded the majority of the crater’s rim, floor, and melt deposit, can now be deemed “completed” in terms of its GIS file and now it can be analyzed for its melt emplacement-to-rim low characteristics similar to what has been accomplished already for 24 of my catalog’s “best” crater candidates.  Alongside Ailey, around ten other craters, the majority of which need the high-resolution imagery to accurately locate their respective impact melt deposits, will also shortly be similarly analyzed and subsequently “finished off.”

Here’s what Ailey crater’s GIS file looks like now:

The next order of business is to summarize all 36 craters into the illustration pictured in my last post (A Mercurian “Hybrid Theory”?), and then do something similar for the craters in my catalog that are rayed.

All in due time….

 

A Mercurian “Hybrid Theory”?

24 of my 36 Mercurian craters have been almost fully analyzed at this point, and so a plot akin to what is present in Neish et al. (2014) and Neish et al. (2017) has been derived for these craters:

Moon vs Venus vs Mercury (updated)

The number of “coincide” craters is small while the percentage of “~90*” and “>90*” craters is notably greater, as it is with Venus; however, there’s a large percentage of “Within 45*” craters — more like what is seen with the Moon.

It may be that the heavily cratered nature of Mercury’s surface is responsible for the “Within 45*” anomaly, but otherwise it appears the factor primarily controlling impact melt emplacement on Venus (direction of impact) is also predominant for Mercury.

This is where looking at rayed craters on Mercury becomes important, as the shape of the crater rays can give insight into the direction of impact.  Here are a couple obvious examples on Mercury (using the MESSENGER Colour Mosaic map):

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Assuming a crater’s rays are asymmetric (the Xiao Zhao image illustrates this nicely), one can simply mark the region where those rays are minimal to imply a direction of impact.  Using Xiao Zhao as the example, the area where the fewest rays exist is roughly the NNE implying the projectile struck the surface from the NNE.

And then there are craters like Hokusai, that exhibit no such trait; all its rays are, more or less, symmetrical in their radial pattern.  Does this imply the impactor that made Hokusai struck ground roughly vertically?

The remaining 12 craters of my catalog need MDIS-NAC imagery to supplement the mosaic imagery already present — unfortunately, said imagery for these craters is not the best, so the MDIS-NAC is meant to clear things up enough to resolve the melt pools and/or crater rim and floor.  Once I can get Isis3 to cooperate with these image files, I can post another useful update!

 

Some “life-hacks” for enjoying a Solar Eclipse.

Today, much of North America got to enjoy a rather nice-looking Solar Eclipse.  Me included!

Viewing an eclipse in progress is best done using a telescope decked-out for the job.  For example, at Western U such telescopes were available for public use during a special event geared to this eclipse — here’s what the eclipse looks like through one such telescope (we got 75% at “maximum” here in London, ON):

IMG_0596

But, what if you have no such luck and would still like to catch a glimpse of the event?  Here are some cool tricks virtually anyone can take advantage of the next time they find themselves in the right place and time for a Solar Eclipse:

Using your phone’s camera:

It’s a bit tricky, but one can achieve some fairly good results when done properly.  Basically, you use your phone’s camera to take an “indirect picture” of the eclipse.  If you point your phone’s camera directly at the sun (this is the tricky part, because you need to angle your phone without also looking upwards lest you accidentally look directly at the sun), at the proper angle you should see a disk-like “reflection” in your image hovering near the sun itself.  Depending on how far along the eclipse is, the reflection should appear as if it has a “bite” taken out of it; this is the eclipse!  Here’s an example of what I’m talking about here:

IMG_0593

The hand-made “pinhole camera” method:

Using your hand, make an “almost-fist” with it such that the sun’s light can still pass through the gap in your fist and onto the ground below.  During the eclipse, it should appear as if a crescent-shape of light is cast onto the ground behind your fist.  Below is an example (this method’s comparatively less tricky, since you don’t need to avoid looking up in order to ensure a good result):

IMG_0598

If you happen to own a telescope of some kind…:

If you own a telescope, but not the resources/know-how to set it up for an eclipse then fear not!  Your as-is telescope is still sufficient so long as you also own a square of cardboard.  Using the cardboard, orient your telescope towards the sun (again, don’t use your own eyes!); once properly oriented, the disk should show up on the cardboard — hopefully being occluded by the Moon!  If your telescope has a pinhole lens attachment, installing that to your telescope should make the resulting image clearer.

Cheers!

 

This is a test … of my crater-melt analysis method.

MDIS-NAC images have been downloaded for all the craters in my catalog that have useful NAC files worth downloading — all except two, if I remember correctly.

But, over half of my craters are already fit enough to be analyzed for melt and rim-low locations and so that is what I attempted to do this past week or so.  Below is the gist of what I’m doing here:

Balanchine crater stats

Using the grid-like object, superimposed over the original GIS file, I mark out where the highest concentration of melt (in purple) is as well as the most likely location of the rim-low (in red).  In the case of Balanchine crater, above, the location of this melt pool is in the W-WNW wedge, while the rim-low can be found within the NW-NNW wedge; this means that the melt is predominantly located within 45* of the rim crest low.

A number of craters need the MDIS-NAC for better locating the melts (and in a couple cases the crater floor), so that will be my next task at-hand.  Then, I can add grids to those craters as well and fix up any hiccups that the already-completed craters had during this first run of mine through this process.

Milestones for Summer 2017:

For me and my supervisor….

What I’ve done so far:

>>GIS files for most of my 36 craters have been created, with rim, floor, and melts shapefiles made for each.

>>MDIS-NAC files have been downloaded for all named craters (around 19 craters).

What I want to complete by September:

>>Download MDIS-NAC imagery for my unnamed craters and render all MDIS-NAC files in GIS to aid in completing the handful of crater GIS files that remain incomplete.  [1 week + 1 week, max]

>>Complete all rim, floor, and melts shapefiles for remaining craters.  [1 week, max]

>>Acquire MDIS-derived DTM map(s) from Preusker et al. (2011/2017/2017) for any outlying craters that still exist — if time permits, perhaps even add some southern hemisphere craters to my “catalog.”  [1 week, max; 1-2 weeks for S.H. craters]

>>Conduct a statistical analysis on these craters, locating where the majority of melt emplacement is w.r.t. each crater’s rim crest low and then compare my results to the Neish et al. (2017) results.  [1-2 weeks, max]

>>Analyze all the rayed craters in my “catalog” for evidence of impactor direction, perhaps using MESSENGER’s false-colour mosaic.  [1 week, max]

>>Hope to begin to write-up my thesis come September (the above should take 6-8 weeks to complete, assuming no hiccups or what-not along the way).

I hope to have completed the first “to-do” objective by the time I draft my next blog post here.

Mercury’s “Group of Seven.”

The “Group of Seven” was the name given to a number of Canadian artists who painted landscapes in the same style at around the same time; the original group was:  Franklin Carmichael, Lawren Harris, A. Y. Jackson, Frank Johnston, Arthur Lismer, J. E. H. MacDonald, and Frederick Varley.  Tom Thomson was noted as being the “founding father” of this artistic movement that was predominant almost 100 years ago now.

Tom Thomson’s ‘the Jack Pine’ (1916) ~ from Wikipedia

A little Canada hype, since it’s turning 150 this year….

My first GIS-processed crater results are well on their way to being completely analyzed.  The best MDIS and MLA data have been attained for seven Mercurian craters so far.  These craters are:  Abedin, Hokusai, Stieglitz, and four unnamed craters.  Mercury’s “Group of Seven,” if you will.

unnamed crater 4
An example:  One of the unnamed craters…, currently possesses the largest melt deposit (wrt crater size) of all 36 crater candidates.  Melts highlighted in lavender, crater rim drawn in blue, the crater’s “floor” is coloured green, and the red contour line is to highlight the crater’s rim crest low.

All seven craters reside at a latitude greater than 45*N; Hokusai and Abedin are neighbours, and the four unnamed craters are also neighbours to each other; Stieglitz is the closest of the craters to the North Pole, and is located nearest to Hokusai; most of these craters can be found within 90* (E or W) of Mercury’s “Prime Meridian.”

The other craters in my list are also being prepared; unfortunately, virtually all of them have very poor MLA data and so it looks like the next best thing for me is to use the “Mercury MESSENGER Global Colorized Shaded Relief” map with a resolution of 64 pixels per degree (ppd).  For comparison, the MLA imagery used for the seven craters above is at ~170 ppd while the MDIS mosaic imagery is at 256 ppd.

More of that in later updates, though….

Fun-Fun-Fun!

GIS project files are currently being made for the original 13 named craters for which MDIS + MLA snippets have been obtained.  The MDIS crater files were easy enough to obtain, but the corresponding MLA was trickier — north + south lat. for MDIS + MLA are the same as well as the east long., but the west long. values for MLA go from 180 to 360 instead of -180 to 0 as with the MDIS.

Once I realized that, I was able to crop out crater files from the MLA that would have the same dimensions as the corresponding MDIS files as well as be centered over the same crater (unlike in a previous post featuring John Lennon where the MLA image I thought was of Hokusai actually is not!).  Then, it was a matter of making sure QGIS would actually render each MDIS + MLA image on top of each other — easier said than done!

Interestingly, I expected the two maps to be misaligned by 180* (or something similar).  Instead, the maps’ boundaries aligned perfectly but the craters themselves weren’t aligned between the MDIS and MLA data-sets.

QGIS screenshot (MDIS + MLA full)
MLA map overlain on the MDIS map in QGIS; the boundaries match but the craters therein do not.

QGIS screenshot (misalignment confirmed...)

Thanks to some ISIS help from Dr. Neish, the use of “maptemplate &” in tandem with “map2map &” allowed my cropped-out craters to be properly rendered in QGIS under a sinusoidal projection centered upon the crater itself.

Abedin_dataMatches

Abedin crater file:  images match, now to get rid of those annoying polygons and to begin the actual analysis process.

Now the fun stuff can begin!  Contouring the MLA file for each crater will help me determine the most likely location of each crater’s rim crest low, and from there I’ll be able to correlate to where the melt deposits are located and thus compose, hopefully, a more accurate plot of Mercury’s complex craters for comparison with the Neish et al. (2017) figure concerning the Moon and Venus.

All in due time….

I Haz Resultz!!

After a week or so of cataloging all the unnamed craters alongside the named craters I already cataloged, as well as re-inducting several more craters I previously discarded and even obtaining a number of brand new candidates, I — at last! — have some cool new results!  **and another .ppt file of craters & results to show for it….

^_^

My Mercurian crater count now is the highest it’s ever been, at 36 (19 named & 17 unnamed).  The smallest crater is now an unnamed crater @ 19.93 x 63.58 with a diameter of only 16 km (the largest is still Abedin @ 116 km wide).  I even have a melt flow crater now (see below)!

Area west of 19.6 x 81.29, note the darker material (via MODE).

As for the results:  “Figure 3” of Neish et al. (2017) shows how craters whose exterior melt deposits tend to coincide with their rim crest low dominate the Lunar complex craters studied, while on Venus the majority of the craters studied had their melt deposits found around 90* or greater from the low.  As for Mercury, analyzing the 36 craters using JMARS has yielded the preliminary result of possessing a large number of craters in the “coincide” area (like the Moon) but also a large number in the “>90*” category (like Venus).  This implies that Mercury lies intermediate to the Moon & Venus, when it comes to impact melt emplacement.

As hypothesized!  Yay!

So… what does this mean?  Well, my initial hypothesis here is that there could be two factors at play here:  First, although Mercury has higher topography (averaged over its entire surface) than Venus it may actually have slightly lower topography than the Moon; thus, unless the Mercurian crater in question is found in a high-topography area a crater’s melt will tend to emplace more like it does on Venus — that said, there is still high topography, hence the large “coincide” value.  Second, because complex craters on Mercury tend to be deeper than those on Venus yet shallower than those on the Moon it could be a matter, in some cases, of the structure of the crater itself; deeper craters on Mercury (w.r.t. crater size) may deposit melt more similarly to craters on the Moon, while shallower craters may deposit more like on Venus — where impactor direction is more important (something I’ll have to check, eventually, for Mercury by looking at the ejecta patterns about rayed craters…).

Analysis of my Mercurian craters in JMARS is a first step, to see what I’d find.  Now, the real analysis begins with downloading MDIS + MLA files for each crater and compiling them all using ArcMap.  That’ll keep me busy for a couple weeks, I think!

 

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