Simulating Giant Sound Waves on Mars

Hello, again!

It’s time for another installment of “a day in the life of an awesome physics student at Embry-Riddle.”

Well the summer is in full swing; I had my first exam on Thursday, which was also my first exam of grad school, as the class I’m taking is my first master’s class for the accelerated degree. I was really confident, which means I either aced the exam or bombed it – you never really know until you get your results back. I’ve never taken summer classes before, but so far I think it’s pretty awesome. The material moves at a quick yet manageable pace, and it’s nice to only have one class to worry about after the last four semesters of 16-17 credits. My only complaint about summer classes is the “summer” part – why is it so hot outside? It’s unnatural. I really wasn’t born to live in the south; I can handle a -20º wind-chill, but as soon as the thermometer climbs above 90º that’s when I give up and hide inside. Not to mention it rains so much! (I promise I won’t complain about the weather in every entry.)

I’ve had a lot of free time, which is unusual for me, so it’s been nice. Lately I’ve been learning some new acoustic guitar songs, watching old seasons of Buffy the Vampire Slayer, and leveling a blood elf warlock. And let me just take a moment to talk about how much I love living in my own apartment off campus. Everything is finally clean, unpacked, and decorated to my liking, and I can listen to loud music in any room at any time and nobody complains about my volume, musical tastes, or singing. It’s great. I live only two minutes from campus, so it’s a nice, short commute every day. Once I figure out how to reduce my electric bill everything will be perfect!

Image of Mars’ Gale Crater from Google Earth. This location was used to generate the profile used in our acoustic wave simulations. Gale Crater was the landing site of NASA’s Curiosity rover, which landed last year.

My days are spent sitting up in the Lehman Building’s Space Physics Research Lab (which will henceforth be referred to as “SPRL”) working on my project for the CEDAR conference in late-June. I mentioned it briefly in the last entry, but I think I should elaborate, since that’s what got me this gig as a blogger. CEDAR (which stands for “Coupling, Energetics, and Dynamics of Atmospheric regions”) is an NSF-sponsered yearly atmospheric sciences meeting that focuses on instrumentation and modeling of the middle and upper atmosphere. I am working with Dr. Snively in the Department of Physical Sciences to adapt his atmospheric wave model to Martian conditions so that we can see how atmospheric acoustic and gravity waves, which are a bit like ocean waves, but in the atmosphere, propagate on Mars in comparison to Earth (if you’re interested, my project abstract is here).

Some plots of relevant atmospheric data on Mars generated by the profile used in our simulations.

We are using MarsGRAM (Mars Global Reference Atomic Model) data provided by NASA’s Marshall Space Flight Center to specify many different properties of the atmosphere, which has proven very interesting! This data is then used to generate a profile, which essentially shows the temperature, density, pressure, etc. as you travel up through the atmosphere (it’s really just a big table of numbers), and then the profile is loaded into the wave dynamics model. The model produces a simulation based on some inputs, such as frequency, amplitude, etc., and we watch how the wave behaves as it moves upward.

Animation of a nonlinear acoustic wave traveling up through the Martian atmosphere. The one-dimensional simulation is laid over the two-dimensional simulation in order to determine that the results of each are valid. This wave has a frequency of 0.032 Hz, which corresponds to a wavelength of about 31 km. (Click on thumbnail to watch animation.) Note that the axes correspond to the 2-D results (and are in meters – please disregard the error in the labeling.)

This past week we successfully simulated an acoustic wave in both a one-dimensional and two-dimensional model and confirmed that the results agreed. Acoustic waves are really cool – they are essentially giant sound waves that move up through the atmosphere until the air becomes too sparse and viscous, causing them to dissipate. We’ve found that this happens really quickly on Mars compared to Earth, due to the increasing viscosity at higher altitudes. The waves we have been simulating have frequencies of about 0.03 Hz. For perspective, note that the average human can hear frequencies ranging from 20-20,000 Hz, so these waves are much larger and lower-frequency than ordinary sound waves.

The next phase of the project is to simulate two-dimensional gravity waves, which I will talk about in my next entry!

Before I close out this entry, I wanted to touch back on what I said last time about going where life takes you. I came into Riddle as an Aerospace Engineering student, but was converted to Engineering Physics after my first semester due to the fact that I love physics and space and don’t really care about designing airplanes (blasphemy, I know.) Deep down I definitely feel like an EP student, and never once regret my change. In fact, the more I go through my coursework, the more I find myself leaning towards physics and research and away from actual engineering – I took the “gauntlet” (solids, dynamics, and fluids, which are engineering sciences classes you take your sophomore year), and pretty much hated them (though I did like fluids, but that was because professor Davids is awesome!) Plus I am loving what I am doing here in SPRL. I’ve been thinking a lot about what I’m going to do after Riddle, and, while my plan had always been BS then MS then Work in engineering then PhD maybe later, I am thinking more about going straight onto my PhD and getting involved in space and astrophysics research.

Tune in next week, I’ll have some really cool Mars stuff to share with y’all! (Yeah, I’m becoming a southerner. I say that now.) Be sure to email me if there’s anything you’d like me to write about Riddle, otherwise I’ll just keep rambling on about my life in every entry.


From Snow to Sunshine

Hey everyone!

I wish I knew a better way to start my first entry than with the obligatory words “my name is…” oh wait, there we go.

My favorite cow and signed Halestorm album.

I’m Lynsey, and I think “quirky” is a good word to describe myself. My interests are all across the board: I’m an avid musician, a lover of math and science, a gaming nerd, and I have a strange obsession with collecting cows (plastic and stuffed – not real cows.) The walls of my apartment have space shuttle posters, vinyls, and signed photographs from the cast of Star Trek (why yes, I have met George Takei), people who have actually been to space, and rock bands like Evanescence and Halestorm (bragging rights: Lzzy Hale has given me a hug.)

I was born and raised in the Land of 10,000 Lakes. The state where we drink pop (not soda!), shop at the Mall of America (I even worked there for a while), and sometimes have snowstorms in May (you think I’m kidding, but I’m really not.) You’re probably wondering what got me to move 1,500 miles south, where there are palm trees instead of pine trees and it’s way too hot outside. I’ve just finished my second year at Riddle, but before I get into that I want to tell you the story of why I chose to come here in the first place.

In order to explain why I came to Riddle, I have to start a bit farther back. It was a cold, snowy evening in 1993… just kidding! Anyways… Throughout my whole life I knew where I wanted to go to college. I talked about it since at least fifth grade; I always said that someday I would go to –nope, not Embry-Riddle! But that’s what makes the story all the more interesting. If you asked anybody who knew me at any point in my childhood, they would tell you I wanted to go to MIT. All through high school whenever I did something I had a constant voice in the back of my head asking, “how will this help my chances of getting in?” I had a goal, and everybody knew it. I should mention that, if you’re reading this and thinking I’m just at Riddle because I didn’t get in, keep reading, that’s not the story.

Senior year of high school always seems so far away, and then somehow it sneaks up on you. Before you know it, it’s time to actually apply to the colleges you’ve been looking at and dreaming of attending. I worked effortlessly on my applications, applying to several big name schools. Embry-Riddle first caught my eye because I saw it listed number one for Aerospace Engineering, which was my original major. So I did a bit more research, and I thought it seemed awesome – a great backup (do you think they’ll let me say that word in an admissions blog?) After taking the ACT twice, the SAT three times, and buffing my resume to glistening status, I submitted my college applications and waited. And waited. And waited. One day I got my acceptance letter from Embry-Riddle. It was definitely an exciting moment, but I was still hanging onto hope for my dream school, and didn’t think much of the acceptance at the time. Time passed, and my early action application to MIT got deferred to regular action. It was a set-back no doubt, but I held onto hope. Later I got my financial aid letter from Embry-Riddle, and found out that I had been awarded some pretty generous scholarships, as well as admission into the honors program. Things were suddenly falling into place in a way I hadn’t expected.

My obligatory picture in front of the Wright Brothers statue from when I visited campus in March 2011.

When February rolled around I was presented with the question: which school do I want to go tour? I applied to five schools – four of which were over a thousand miles away, so naturally it was a “pick one trip” kind of deal. I had this gut feeling that I would be going to Embry-Riddle. It wasn’t an abandonment of my dream in any way, it was just a feeling that I can’t really describe; I’ve felt it a couple times in my life, and they’ve all been massive, defining moments. After a lot of thought, I decided on a trip to Daytona Beach to tour the campus. Long story short, that’s all it took. I fell in love with the campus. I stayed overnight with one of the RAs and sat in class with her the next morning. Then my parents picked me up, and we went over to the cashier’s office, where I put down my tuition deposit. I was a Riddle student.

You’re probably wondering if I missed a point in the story. What about MIT? Did I get in? You know what, I didn’t know yet. I wouldn’t hear back for another two weeks. But I was so sure I was at the right place and making the right decision that the word backup immediately vanished from my mind. I was so excited to start in the fall, because I had found my dream school in a place I didn’t even think to look. I learned a major lesson from this decision: sometimes life has a way of working out the way it’s supposed to, and all you have to do is follow it. I know that sounds cheesy, but it’s so true. I love Embry-Riddle, and I don’t regret my choice for a second.

I’m really looking forward to sharing my Daytona Beach shenanigans with you. This summer, apart from taking a couple classes, I’m spending my days in the Space Physics Research Lab as an undergraduate research assistant. My current project involves developing a model of the Martian atmosphere in order to simulate acoustic and gravity waves – I’ll talk more about that in the next entry, but for the meantime, if you’re interested, you can read my conference abstract here.

Part of the living room of my new apartment, which I absolutely love!

This is my first summer here in Daytona Beach, and I’m enjoying it so far (apart from the temperature, that is.) I just moved into my first apartment off-campus after two years of dorm life, and I absolutely love it. Aside from working days in the lab and taking a math class, it’s been nice to have some free time, as I keep pretty busy during the school year. My evenings have been essentially empty, so I’ve had a chance to play some video games and get back in touch with my acoustic guitar.

Even if I may seem crazy, I’m pretty friendly, so feel free to hit me up with questions, comments, fan letters, etc. Especially if there is something you’d like me to talk about in my next entry!

That’s all I have for now. I’m still trying to think of a cool catch phrase to close with, so stay tuned for that. In the meantime, I think I’ll go with “Live long and prosper.”

Until next time…