My Project!

So far I've mainly written about the fun outings and neat tours we've gone on.  I'm sure you're all dying to know about why I'm really here in the first place.  (Yes Mom, I actually do work).

So, the Lunar and Planetary Institute (LPI) is a NASA funded division of the Universities Space Research Association.  Most of the staff here bounce back and forth between LPI and the Johnson Space Centre (JSC).

This Lunar and Planetary Summer Internship program takes students with an interest in planetary sciences from across the world to work one-on-one with the scientists at the LPI.  Due to the varied nature of some of the projects, many of my colleagues do lab work at JSC.

[1] Global radar view of Venus from the Magellan
"JPL must have had an excess of orange ink
the day they printed all the Venus images" 

Project topics range from meteor impact creators, lunar mapping, atmospheric modelling, mineral synthesizing, planetary surfaces and others.

I'm working with Dr. Allan Treiman, and our project is on analyzing radar properties of Venus' highlands to provide insight into surface chemistry processes.


Let me try to explain it better.


First of all, Venus is covered in thick clouds made of sulfuric acid.  This makes it really difficult to see what is on its surface, because we can't take pictures of it like we do the moon or Mars.  Instead, our most recent information of Venus comes from the Magellan satellite, which orbited Venus for two years, from 1992 to 1994.  Even though we couldn't take pictures of its surface, we are able to use some other tools to figure out what is down there:

Altimetry - Resolution of 8x10km - Magellan was able to tell how high it was above the planet's surface,

[2]The Magellan spacecraft as it was deployed

which allows us to produce rough topography maps. 

Emissivity - Resolution of 15x23km - Measurement of how much radiation a surface emits.  You can tell apart different materials by their emissivity values.

Synthetic Aperture Radar (SAR) - Resolution of 75m - Active "pinging" of Venus' surface, and measuring the intensity of the waves that bounce back

Radar is so far the best tool we have for mapping out Venus.  It penetrates clouds easily, and can give pretty high spatial resolution images.

There is an established inverse relationship between elevation and emissivity on Venus, that is to say, as elevation increases, emissivity decreases.  This is really interesting, because the only real variable that we know of affecting Venus' mountains is temperature.  Like on Earth, it gets cooler as you go up a mountain than if you stay at sea level.  On Venus, instead of using sea level (because there aren't any oceans), we use a set datum, which is mean planetary radius.

There are several hypotheses as to why emissivity might be increasing with elevation on Venus' mountain tops.  One of the more popular recent theories is metal precipitation.  Since Venus is really hot, it is possible that a lot of metallic compounds exist in a volatile state near her surface.  As these metals cool down, they can precipitate out of the air, like when it's cold out water precipitates as snow.

Another hypothesis is that there is a mineral present that is undergoing different degrees of temperature-dependent weathering.  Imagine an iron nail rusting; there are different variables that determine how quick or slow the corrosion occurs, including oxygen concentration, pH, presence of water, and temperature.  Venus' atmosphere is consistent at the elevations we're looking at, so the only real factor that can control this weathering is temperature.  Previous authors' have suggested that the change in emissivity is due to iron sulphides, such as pyrite, but later works have shown that pyrite is unstable.  Other minerals have been suggested.

A third hypothesis is that there might be presence of a ferroelectric compound.  Don't worry if that term is intimidating; it took my advisor and I awhile to figure out what was meant by that.  Essentially, ferroelectric materials show a really interesting behaviour.  They have a constant dielectric constant as temperature increases, until they reach a critical temperature, at which their properties spike dramatically.  As temperatures continue to increase, these properties slowly decrease along a decay curve.  Few minerals show are considered to be ferroelectric, making this a confusing, complicated hypothesis, but it actually fits some data quite nicely, which I will get to shortly.

My project is trying to explore this elevation-emissivity relationship, and to see if I can refine it further using higher spatial resolution data.  Since we don't have any new data from Venus since Magellan, it is important to look at what we have in new ways. Emissivity is the complement to reflectivity (1-Emissivity = Reflectivity), so we decided to look at the SAR brightness instead.  This gives us the resolution of 75m instead of 15x23km.

Exciting!

Example of my polygons.
Breaking the Venus-orange stereotype one map at a time.

So, my job is to find suitable areas and to take radar brightness and elevation values to see how they compare with one another.  I accomplished this by making series of polygons, and averaging out the pixel values contained within each polygon.
I didn't take the polygons arbitrarily, of course. Care was taken to avoid major faults and areas with high surface roughness.  This attention to detail is what allowed us to produce a tighter graph, with less scattering.

Shown to the left and below is one of the areas I examined on Ovda Regio, one of the largest mountain ranges on Venus.

Essentially the same map as the colourful one,
but now you can see more of the surface topography.

Unfortunately the scale bar doesn't show up so well, but the image to the right is approximately ~120km across.

Notable features include the smooth ramp in the middle.  It extends from higher to lower elevation, and the change in reflectivity (brightness) is apparent on this image.  To either side are high plateaux with some interesting dark spots on them.  These dark spots are more or less at the highest elevation, and give us a unique cluster of points on my graph.  Given that the emissivity data is 23km across, many of these areas were averaged out and overlooked in previous analyses. Arvidson (1994) [3] collected a few points which demonstrate the drop in radar brightness at the highest elevations, leading the hypothesis of ferroelectric materials present.  We've found a few hundred of these points, supporting this interpretation.

So, here are the results:

Previous work by Arvidson (1994). [3]
Notice that there are very few points (~6) at the high elevation, high emissivity range.

Harrington (2014).  My graph.
Notice the cluster of points at high elevation, low radar backscatter coefficients

So, this is pretty exciting in the field of Venus research!  I finish writing up my abstract this week, and will be presenting at the intern conference on August 7th.

Cheers!

[1] "Venus globe" by NASA - http://photojournal.jpl.nasa.gov/catalog/PIA00104. Licensed under Public domain via Wikimedia Commons -http://commons.wikimedia.org/wiki/File:Venus_globe.jpg#mediaviewer/File:Venus_globe.jpg
[2]"Magellan deploy" by NASA - http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-spacecraft.html. Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Magellan_deploy.jpg#mediaviewer/File:Magellan_deploy.jpg
[3] Arvidson, R. E. (1994) ICARUS 112, 171-186.

Elise's Birthday Weekend Part III (Austin + Hamilton Pool)

This isn't the most representative shot of Texan buildings

So we get to Austin!  Austin follows the same colour-coding trend that I'm noticing with most of Texas. Most buildings in Houston, San Antonio and Austin are sort of a pinky-beige colour with red accents.  This is in contrast to Vancouver, where buildings follow a blue and green theme.

Upon arrival, we split into two groups based on interest.  My group went to go tour the capitol building, while the others went to check out a music shop.

The Texan State Capitol dates back to the 1880's

Confederate soldiers monument

Monument to fallen volunteer fire fighters

There are really nice gardens on the building grounds

The capitol is crowed with a statue of the Goddess of Liberty, holding a 5 point star.

Is there much more Texan than wearing a Texas flag shirt, that was bought at the Alamo, in front of the Texas State Capitol?  I think not.

We were happy to see that entry was free.  I was surprised that we had mostly free-run of the place after passing though security.  It was self-guided, and while certain areas were roped off, there weren't any guards around.

The doorways are all intricately carved

Even the door hinges are decorative

Mosaics are made in the floor tiles

Each of these seals represent one of the six nations that have governed Texas

Portraits of passed governors circled the main foyer. 

Looking up at the interior of the dome

Each floor branched outwards to galleries and offices

Stephen F. Austin is known as the "Father of Texas", leading the colonization into the region

Sam Houston lead the victory of the Texan Revolution, and was elected President of the Republic of Texas twice

After leaving the capitol, we met up with the others and went for dinner.  This time I was spared a mariachi band.   We parted with those who were only doing a day trip, and checked in to our youth hostel.  It felt like a normal youth hostel to me, albeit a little small and the weird Adventure Time-style drawings all over the walls.  I lament not having any pictures of those.  There was a painting of two 6ft tall cartoon men whose beads were merging together into a heart beside my bed, across from a purple princess with a glowing crystal.  In the restroom there was a plethora of cartoons, including a kid's balloon who was jealous of an older hot air balloon.  Weird.

We hit up 6th Street in the evening before retiring for the night.  We found a decent, but loud, place called Darwin's where we listened to a live band.  I'm not quite sure what you'd call the genre, but I would qualify it as an American rock-country style.

The next day we swimming in the Hamilton Pool Preserve.  It was gorgeous there.  There were ferns growing out of the top of the overhang, and many swallows were nesting up there.

Water falls over the edge (15m) into the pool

The rock here is limestone, like at McKinney Falls.   The pool was created when an underground river collapsed.

Ferns grow wherever there is adequate moisture.

Silhouette of Tim

And such concludes Elise's birthday weekend!  It was a pleasure.  Thank you to everyone who came out with us to make it special!

Cheers

Elise's Birthday Weekend! Interlude (Texas Billboards)

We drove to Austin from McKinney Falls.

First, I would love to interject that Texas has some of the best billboards along the interstates highways. They are all funny, even if they aren't supposed to be.  Some of the stellar signs that come to mind include:

Vodka Ad:  "The reason Edward Snowden wishes he seeked asylum in Poland"

Waterpark Ad:  "Wet your pants"

Impeach Obama Ad:  "He failed to live up to Kennedy's dream" *Coupled with image of the moon landing*

Then there was Buc ee's, which was a caliber of its own.  We had never encountered these before, and could not for the life of us figure out what they meant. Billboards were posted at uneven intervals along the interstates, each with the cartoon beaver logo with slogans such as:

"I dream of beavers"
"Got porcelein?"
"The Eyes of Buc-ee's are upon you"
"Keep calm and Buc-ee on"
"Don't stay thirsty my friends"
"All roads lead to Buc-ee's"

Eventually we came to the conclusion that Buc ee's is a truck stop chain, and we ended up passing two of them over the course of the weekend.  Steven was sleeping in the back of the car when we passed the first one.  Kaitlyn woke him up to point out that we finally found the Buc ee's.  Later in the day, he asked us, "... did we actually pass a Buc-ee's, or did I dream it?"

Perhaps we will dream of beavers.

Elise's Birthday Weekend! Part I (San Antonio+McKinney Falls State Park)

I had a fantastic birthday weekend!

We started off fresh and early the morning of the 28th.  While meeting up with the carpool (around 6:30am), my colleagues surprised me with a wonderful card and cake!  Ellie made me a maple cake, made from real Canadian maple syrup, decorated like the Canada flag!  All the interns also signed a nice card for me, which jokingly had Barak and Michelle Obama on the front.  It was pretty funny.

Happy Birthday to me!

"Uh, thanks?"

Hurrah!  Then it was on for the car ride.  We all agreed that it would be beneficial to stop in some small hick town for gas, in part due to the cost, and in part due to the experience.  The gas station we stopped at sold low-quality cowboy hats and Texas-pride baseball caps, such as the camo-patterned cap which is rendered ineffective by having a bright "TEXAS" and cow skull embroidered largely on the front.  They also sell individual pickles here, so that's weird.

This stop got me pumped.  I was excited to be here, excited to be in Texas, doing Texan things and going to Texan places.  I was stoked that we were going to the heart of Texan pride:  The Alamo.

I didn't know what to expect from the Alamo.  I assumed it would be a small, crummy fort in the middle of nowhere.  I was entirely unaware that the city of San Antonio was built around the site.  I was also unaware that there would be beautiful, well-kept gardens within the walls.

The fortress was built in 1744, as a Roman Catholic Mission compound

Monument to lives lost at the Alamo

The fortress was passed from Spanish to Mexican possession after the Mexican War of Independence in 1821.  

Texans gained control of the Alamo in 1835, during the beginning of the Texan Revolution.  During this intervals, Texans had driven out all Mexicans out of what was "Mexican Texas".

Only 189 Texans were stationed at the Alamo when 1,500 Mexicans laid a 13 day siege to the fortress in Feb-Mar 1836.

During an assault lead by President General Antonio López de Santa Anna, all of the Texan defenders were killed. There were approximately 600 Mexican fatalities.  

The defeat rallied the Texan army, leading to an surprise attack launched at Santa Anna.  The soldiers were heard crying, "Remember the Alamo!" during the Battle of San Jacinto.  The battle lasted 18 minutes, with Sam Houston leading the victory, ultimately securing Texan independance.

In one of the courtyards, an older gentleman told us the story of the Alamo, and the history of the formation of Texas.
I learned a lot that day.

I bought a t-shirt at the gift shop since they didn't charge any entry fee.  Afterwards, we walked along a canal to find a restaurant for lunch.  They have a gorgeous river!  It really caught me by surprise.

We ended up at a Mexican restaurant called "Ritas on the River", which specialized in margaritas.  Some of the servers had the slogan on their shirts, "Margaritas so good, you won't remember the Alamo!".   They had a mariachi band.  Ellie had to be a terrible person and tell them it was my birthday.

"Noooo.... Whhhhyyyyy?"
Photo courtesy to Tim

We set off to drive again, but instead of heading straight to Austin, we take a detour to McKinney Falls State Park!

During the Cretaceous, a lot of the land now known as Texas was submerged under a shallow sea

Limestone precipitated in this time interval, creating the bedrock present in this park.

A nearby volcano ejected debris into the sea, depositing soft volcanics along with the limestone

Because the volcanics were softer than the limestone, they eroded away more quickly allowing for river channels to undercut the limestone banks

While I may look pensive, I am really just lamenting my lack of swimsuit.
Photo courtesy to Ellie

Group shot!  From left to right:  Steven, Ellie, Zack, Me, Kaitlyn, Tim, Alyssa, Stefan, Molly
Photo courtesy to a kind stranger

Hurrah!  To be continued.