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J. W. Daniels, MSc

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

What I know so far…: Mercurian craters.

With “Space Day” coming up next week @UWO, I figured it’d be a good idea to jot down what I’ve noted about fresh crater impact melts on Mercury in preparation for that fateful day.

As if I didn’t already have enough to do…!

Here’s what I’ve got so far:

>>15 named craters + 9 unnamed craters = 24 craters in total.  Up to 6 other, less-promising candidates….

>>Smallest crater w/ exterior melt = Ailey crater with a diameter of 23 km; Ailey appears to be on the transition from simple to complex crater form.

Ailey crater

>>6 craters, most of them >100 km in diameter, have more than 1 unique pooling of impact melt.  Most have 2, but a couple, like Hokusai, have 3 or more.

Tyagaraja crater

>>6 craters are found adjacent to older craters, and as such their collection of melt is almost exclusively found within that older crater.  For this group, for some reason the older crater tends to be located just to the north of the fresher crater.

Balanchine crater

>>For the remaining craters, the majority of the smaller complex craters, have only 1 collection of melt present.

Plath crater

To recap, here’s what Neish et al. (2016) & Neish et al. (2014) have found for Venus & the Moon, respectively:

>Venus — 19% coincide, 31% up to 45*, 17% up to 90*, and 33% >90*.

>Moon — 53% coincide, 27% up to 45*, 7% up to 90*, and 13% >90*.

 

That’s all I got at the moment!  The next step now is to locate the rim-crest low for each crater, and for that I’ll need to figure out the topography dataset….  I’ll also stress that my work so far is preliminary and I still have a fair number of things to do yet that hopefully will confirm these initial findings of mine.

The results look promising already, though.  More to come in due time!

[the images are screencaps from:  https://messenger-act.actgate.com/msgr_public_released/react_quickmap.html]

Pi(e) Day!

Did you know today is Pi Day?

Well, now you do!

Every year, on March (3) 14, at 3:14 pm.  How many digits of pi have you memorized?

Me:  3.14159 — thanks to Stargate, of all shows….

😀

Fresh impact melts – the best of the best (so far).

The following are the absolute finest Mercurial craters in possession of impact melt located just beyond their respective crater rims, listed from most to least optimal candidates:

1 = Hokusai (57.75, 16.71; 114 km).  Lots of quality images available, and lots of instances of impact melt residing just outside the crater rim; much of the melt is found along the west-to-south trace of Hokusai, but another large collection exists off the eastern rim as well as a small pooling off the northern rim.

2 = Abedin (61.73, -10.54; 116.25 km).  Virtually all the visible melt can be found off the western (from NW to SW) rim of the crater; once again, a fair number of high-resolution images are available for this crater.

3 = Apollodorus (30.57, 163.28; 41.5 km).  Besides having a fairly unique radial pattern associated with it, this crater also possesses a nice collection of melt located in a sizeable area south of the crater itself.

4 = Seuss (7.65, 33.16; 64 km).  The melts present at this crater aren’t exactly the best-looking, but are found in two very large collections located to the east and south of the crater itself.

5 = Degas (37.10, -127.37; 54 km).  The high-resolution images available for this crater were instrumental, more than most of the other craters I’ve looked at thus far, in determining where the melts were located; there are, in fact, two small collections located south and west of the crater itself.

6 = Kulthum (50.72, 93.56; 31 km).  There are three small collections of melt present, located NE, NW, and SW of the crater itself.  Once again, the high-resolution images were instrumental in determining more exact locations for these melts.

The following craters also contain excellent collections of external impact melts, but are located within a much older crater situated right beside the crater in question (usually just to the north of the fresh crater):

1 = Erte (27.41, -117.31; 242.5 km).  Largest crater in the list overall, at roughly twice the size of Hokusai; there are two large collections of melts, the larger of which are located to the north inside an even larger, older, crater while the smaller is located to the E/NE of Erte.

2 = Balanchine (38.46, 175.50; 38 km).  Melts are pooled within an old crater located between Balanchine and a middle-aged crater located to the NW.

3 = Ailey (45.58, 177.92; 23 km).  Smallest crater in the list, overall; one large pool of melt is located within the old crater located just north of Ailey.

4 = Kyosai (25.16, 4.90; 39 km).  Virtually all melt is located within an older crater located north of Kyosai.

That’s it!  For now, that is!  This list shall be expanded once I search the high-resolution images for all the unnamed craters I’ve identified as promising candidates (still figuring out how to make the site search an area by coordinates…) and I search Braden et al. (2013) for any Kuiperian craters I’ve missed.  I hope to have those results by next week, or so….

[crater data – lat, long; diameter – obtained via https://messenger-act.actgate.com/%5D

 

 

The awesome-est exoplanetary system to-date.

Finding seven “Earth-sized” worlds orbiting within the Habitable Zone (HZ) of a nearby dwarf star is definitely something worth celebrating — even if one has to “fudge” the HZ parameters for four of them to make that happen.

Behold, TRAPPIST-1:

Image result for trappist-1

(https://www.thestar.com/content/dam/thestar/news/world/2017/02/22/what-to-know-about-the-newly-discovered-trappist-1-solar-system/exoplanets2.jpg)

The star in question is a red dwarf located roughly 40 light years away, and the worlds were detected using the Belgian-based TRAPPIST telescope system.  Because we’re dealing with a red dwarf star, and therefore the HZ is much closer to the star itself, chances are very good that most, if not all, of the exoplanets will be tidally-locked to TRAPPIST-1.

The fact that all seven exoplanets are more-or-less Earth-sized, and that at least three of them reside within TRAPPIST-1’s actual HZ, implies the very real possibility that up to three of those worlds, maybe more, could actually hold liquid water and even some form of life.

Like everything else in the Universe, the TRAPPIST-1 system has its own website:  http://www.trappist.one/

Of course, the TRAPPIST telescope itself has a website…:  http://www.trappist.ulg.ac.be/cms/c_3300885/en/trappist-portail

We could literally be within a year or two of confirming a truly Earth-like world, with the launch of the James Webb telescope next year.  If this new-fangled space telescope happens to catch sign of oxygen and methane co-mingling in the atmosphere of at least one of those exoplanets, then it is generally agreed that the possibility for life as we know it is considered to be quite strong since normally atmospheric oxygen and methane readily react to create new compounds (ie, if these gases are detected in noticeable amounts it means these gases are being replenished – the most efficient candidate we Humans currently know of is Life itself).

No matter how one looks at it, the TRAPPIST-1 system is exciting for Science and Humanity in general; unlike Gliese 581 and Gliese 667 C before, TRAPPIST-1’s worlds are confirmed with great confidence; the next step is to spectroscopically analyze the atmospheres of those seven worlds in the hope of detecting the ever-promising O2 + CH4 combination as a promising indication of an alien biosphere.

It just keeps getting better and better!!

 

Do ya wanna… search for impact melts around fresh Mercurian craters?

This week will be the second that I’ll have spent on the new, alternative thesis idea involving attempting to correlate occurrence of impact melts about fresh impact craters on Mercury to the location of the rim-crest highs of those same craters for the sake of comparing the results to Venus and the Moon for any similarities/differences that appear.

I spent all of Reading Week, last week, with my family down in Mickey Mouse Land (Florida, I mean), so naturally not much school work was undertaken….

In preparation for the next stage in the timeline of this new topic – should I decide to commit to it, and abandon the MARSSIM project – I browsed through the craters I’ve chosen thus far, most of them being complex in nature, and highlighted promising occurrences of impact melt just outside the rims of these craters as well as a number of candidates that might possess impact melts upon closer inspection under higher resolution (to be undertaken in the next step in the timeline).

The result of my preliminary analysis, given the limitations imposed by the quality of the MESSENGER images, can be found in the document below:

the-rayed-craters-of-mercury-complex-crater-candidates-for-exterior-impact-melts

[Images in document are modified screenshots of MESSENGER data from: https://astrogeology.usgs.gov/search/map/Mercury/Messenger/Global/Mercury_MESSENGER_MDIS_Basemap_BDR_Mosaic_Global_166m%5D

Should everything go well for me with this project this week, I’ll probably decide to make the switch and start going down this new crater road for the duration of my time here on the Masters train at Western.

 

So, what’s the point anyway?

To switch, or not to switch?

It’s an interesting situation, being told that swapping thesis topics as a Grad student is unwise yet being faced with just such a situation a mere five months in.  In a way, it’s like being caught between that proverbial Scylla and Charybdis….

My current topic, eroding fresh craters with MARSSIM and comparing the results to craters on Earth, is still pretty interesting, but after five months I’m still trying to grasp exactly why anyone besides my supervisor and myself should really care.  Every time I think I have a handle on it, I am shown otherwise.  Perhaps, being offered a topic of study that is far more straight-forward in its primary purpose is worth making the switch in the end?

This potential, new topic still involves looking at impact craters, but in this case I’ll be looking at ray craters (craters with ejected material strewn out radially around it, like a splatter pattern – these are usually the freshest craters) on Mercury; I would be looking at images from the recent MESSENGER mission to Mercury, examining the most promising ray craters for impact melt (rock that was melted by the heat of impact and then re-solidified).  The main objective here appears clear enough to me:  See where the melts tend to bundle-up on and outside the rims of these Mercurian ray craters, then compare the results to what has already been determined of fresh craters on the Moon and Venus in the hope of finding a correlation between the three worlds.

My supervisor has already determined that impact melts flowing out from Venusian craters tend to do so away from the suspected direction of impact of the original projectile, whereas on the Moon the majority of flows appear to lead in the direction of the lowest part of the crater rim.  Examining Mercurian craters, it is hoped that we can figure out if Mercurian impact melts behave more like the Moon’s, like Venus’, or somewhere in between.

neish_2016_lpsc_moon_venus_craters_impact_melt_correlation_figure
Correlation between exterior melt flows and the lowest part of the crater rim for (a) the Moon, and (b) Venus.  “Coincide” means melt flows out from crater rim’s lowest part (“rim crest low”), and “~90*” thus means flow emerges roughly from rim’s apex.  From:  Neish, LPSC 2016 (see below).

neish_melts_lpsc16

To get a feel for this new project, I began by finding promising complex craters from the MESSENGER global mosaic image of Mercury.  Theoretically, the northern hemisphere has the better data, so the craters I looked at are located there.

Here are the best examples I’ve found so far, which cover the majority of complex ray craters listed by Beary Xiao (sharp-faint_rayed-20150722):

Once I finish finding all the promising ray craters, that also show evidence of external impact melt, then the next step is apparently to download higher-resolution images of the select craters from this site:  http://ode.rsl.wustl.edu/mercury/.

But, that’s if I decide to switch thesis projects….

 

Success?

This past week or so saw some more errors in MARSSIM output, but it seems to have culminated in what appears to be a successful “run.”

Since the problem with the Frank Crater run lay ultimately with the way that QGIS converted (improperly) the original DTM (Digital Terrain Model; a 2d rendering of a plot of land) into the ASCII file that MARSSIM could work with, the next step was to try the same conversion process using ArcGIS and see if that turned out any better.  For this, resident Post-Doc, Mike, gave me input data pertaining to Meteor Crater, Arizona.

The run of the first ‘inelev.dat’ file for Meteor Crater gave the following:

outelev-01000-dat-cub-2
Meteor Crater…, sort-of.

Basically, what happened here was the result of a “loss in translation” between ArcGIS and MARSSIM:  While MARSSIM “reads” data from DTM’s the way a Westerner would read a book, ArcGIS does not (it “reads” starting from the bottom of a DTM, for some reason).  As a result, MARSSIM spat out more bad results (see Dr. Tornabene, previous post).

With further tinkering of the DTM conversion done by Mike, an ‘inelev.dat’ file was soon obtained that produced this more amiable .gif output:

crater_movie01
It’s a crater!  Now to fix the crappy-looking erosion….

The result, above, could still be more “ideal,” but at least it looks like it should.  That run was done over 1,000 iterations; the gif below was done over 10,000:

crater_movie_long
Crappy erosion fixed!  Sort-of….

It appears an eroding crater from initial DTM data has finally been achieved.  The alternating white-and-black boxes that slowly encroach on the crater through the gif’s duration is due to the presence of a border in the original ArcGIS DTM of Meteor Crater (which gave a number of zeroes in the ‘inelev.dat’ file).  Barring that, everything else appears fine.

Problem solved?  I guess I’ll find out when I apply the same procedure to Frank….

ICT 2.0 ~ sort-of….

So… after four months of figuring out how all this new-fangled fortran stuff works, I was finally able to acquire an end product right before the start of Christmas break:

crater_movie
Well… at least the strip concerning Frank crater erodes as expected (sort-of).

However, even as Dr. Tornabene‘s prized, personal “commandment” rang in my head (“Know thy data!”) it was helpfully pointed out to me that my input dataset was faulty somehow – as indicated by the above gif.  Back to square one, or nearly-so.

At least, once I can attain an accurate Frank crater dataset, I’ll be able to make a full run of the “inelev” file once it’s been properly retrieved.

From there, I can move onto running Frank over longer timescales; then, I can move onto Lunar craters and stuff!

 

Merry Beardedwhitegod-mas!

In honour of the holiday we know better as “Christmas,” I figured it was fitting to make mention of a number of “Jesus-like” deities that have popped up throughout history thus far – since he’s far from unique:

  • Jesus ~ the one we all know best!  His long, golden hair, flowing beard, and Caucasian complexion are the Catholic Church’s doing.  Because Jesus was a Jew, his real likeness, assuming he truly existed, would jive more with the oldest mosaic depictions than anything else.
  • Mithra(s) ~ the Persian “Bearded White God” that inspired much of the Catholic Church’s depiction of Jesus (down to the birth-date).  When Mithra’s not shown as a lion’s head stuck onto a man’s body, he’s shown as a spitting image of the Jesus we know and love.
  • Horus ~ the man who inspired the “Jesus and Mary” pictures we tend to find in Catholic churches and beyond.  The scene of Mary coddling Jesus is a direct homage to Isis holding a baby Horus.  Like Jesus, Horus accomplished a series of great undertakings while alive.
  • Herakles/Hercules ~ the Greek demigod born of a godly father and mortal mother.  Like Jesus and Horus, Herakles is also well-known for his daring achievements in life.
  • Quetzalcoatl/Kukulkan ~ the Aztec/Mayan “Bearded White God.”  Like Mithra and Horus, this deity takes two forms:  a godly, winged-serpent form and a mortal, bearded-white-man form.  The Aztec likeness even comes complete with a spear-gash on the side of his abdomen (sometimes).
  • Viracocha ~ a “Bearded White God,” of sorts, and creator deity for the Inca people.  He sired two sons, also pale-skinned.
  • Ngeketo ~ a “Jesus-like” figure of the Ngonde people of Africa.  Like Jesus, Ngeketo was resurrected after three days of death; (somewhat) like Queztalcoatl/Kukulkan, he arose as serpent; like Osiris (Horus’ father), he was chopped up into pieces – several times, in fact.
  • Krishna ~ not an exact match, but Krishna’s the Hindu equivalent of the “Bearded White God”….
  • Zarathustra, Muhammad, etc. ~ other “Jesus-like” entities from other extant faiths….

Well… with all that in mind, I wish you all a Merry Christmas!  See you all again in January.

 

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