Tag Archives: talks

My Science Talk NW presentation

Last week, I attended Science Talk Northwest in Portland and participated in their Science Communication Contest. Presentations had to fit within three minutes (with a 30 second grace period), you could not use any slides, and you could use a prop. The competition was specifically for “trainees,” who ranged from undergrads to postdocs.

I didn’t win, but I did make it into the Top 10! The winner and runner-up both did outstanding jobs and used props very creatively (did you know a super soaker is like a placenta, and that drumming can relate to personalized medicine?). I will have to think about how to incorporate props into future presentations about LSST and astronomy. I felt much more solid about this talk than previous three-minute slide-free talks I have given, however, because I began preparing it more than a couple days in advance and incorporated intentional gestures to help remind me what came next.

I was pleasantly surprised to find that, for me, gestures are the next best thing to having a slide or image as a visual memory cue. Deciding ahead of time what gestures to use was partially motivated by a workshop I attended on “The Performing Art of Science Presentation” by Nancy Houfek at the recent AAS meeting. I also appreciated the 30-second grace period, because it helped me be deliberate about my pacing and emphases. I was less likely to panic or speed up if I thought I was running behind.

Say… how is the whole I-work-for-LSST-at-UW-now-and-mostly-live-in-Seattle thing going? Very well, thank you! I only wish I could say the same for my country.

Without further ado, I present an approximate transcript of my #SciTalkNW three-minute talk. (I actually gave this talk twice: once in the initial round, and again in the final round, after some feedback from peers and experts.) When the conference organizers make a video available, I will update this post, and you can be amused at how my memory and the video differ.
UPDATE April 2017: link to my video, link to all the finalists’ videos

What’s your favorite picture of space? Maybe you think of one of those gorgeous Hubble pictures, like the Carina Nebula or the Pillars of Creation. Or maybe you have a memory of going outside at night, far from city lights, and looking up to see stars stretched across the sky.

All of these images have one thing in common: they’re static snapshots. They capture a single moment in time. But most things in space are dynamic and moving! While astronomers can learn a lot about our Universe from images like these, what we really need is a movie.

This is why a team of international scientists are building the Large Synoptic Survey Telescope, or LSST. It’s under construction right now on the top of a mountain in Chile. When completed, this telescope will have a main mirror that’s eight and a half meters across—that’s like 27 feet—and the largest camera ever built, the size of a small car. Inside the camera will be a detector with 3.2 gigapixels. That’s like several hundred iPhones in every snapshot.

When LSST comes online in 2022, it will begin mapping the entire southern sky. Every three nights, it will take one all-sky image. Then, over the course of a decade, it will stitch them together into the highest resolution movie of the night sky ever made. And, it’ll be in full color, because LSST will use six different color filters!

LSST is going to revolutionize pretty much every area of astrophysics. Everything from finding asteroids moving in our own Solar System, to observing stars explode as supernovae in distant galaxies.

But to do this, we recognize that the software is at least as important as the science. My team at the University of Washington is writing software to process the images that come from the LSST in real time. We’re talking 15 terabytes of data every night—that’s more than you can fit on your computer’s hard drive. And we have to process every image within 60 seconds of the shutter closing. Our software will take new images from the telescope, compare them to older images, and find anything that has changed. Those changes will then be broadcast in a public alert stream so that scientists can filter and search to find the targets they’re most interested in. All of our work is open and public, because we want scientists and folks like you to be able to use our tools.

So, in 2022, the movie begins! I am incredibly excited to share the ever-changing, dynamic cosmos with you. We’re going to find new kinds of variable and moving sources we didn’t even know to look for! Coming soon to a night sky near you: everyone’s new favorite space picture. LSST—it’s actually a movie.

Dr. Rawls

My PhD defense took place in Las Cruces on April 8, and was successful! If you’re interested, you can watch my presentation and/or view my slides. However, please be aware the intended audience for this talk is fellow astronomers, not the general public.


I’ve spent the last week or so revising my dissertation, and I’m happy to report it passed the graduate school’s format review today. Once the final copies are printed (yes, multiple copies; yes, printed) and accepted, I will add it to the Astronomy Thesis Collection online and write a post summarizing the main results. I’ll be back in New Mexico in May to celebrate graduation with my family, and I intend to consume even more burritos before embarking on a road trip north.


A Thesis, Proposed

Graduate school is a bit of an odd beast. It’s not really college, it’s not quite a job, and it’s certainly not easy. In the US, getting a PhD in the sciences typically involves a couple years of classes, several exams, some work as a teaching assistant, and eventually a self-directed research project called a thesis. The whole shebang takes some 4-8 years on average. AstronoMerrdiff’s graduate school journey began in San Diego with a somewhat atypical MS-only program, and then wound its way to Las Cruces for a PhD. (The “normal” path is to earn a Master’s degree en route to the PhD at a single institution.) Finally, back in February, after years of related and not-so-related research, successfully completing a host of departmental prerequisites, and a hectic few days of last-minute changes, I stood in front of my department and outlined the project I will undertake for my thesis dissertation:

Red Giants in Eclipsing Binaries
as a Benchmark for Asteroseismology.

Any questions? …Well, since this is my primary purpose in life for the next while, I figure the least I can do is spend a few paragraphs explaining my own little corner of astronomy.

In a nutshell, I’m studying red giant stars that are in eclipsing binary systems. Many of the giant stars have sound wave oscillations going on inside that we observe as small changes in brightness (this is called asteroseismology, and tells us about a star’s interior which is otherwise impossible to see). But not all of the giant stars oscillate. I want to figure out why. The fact that these stars are in eclipsing binaries makes them relatively easy to physically model and characterize. We think the oscillations might be weaker or non-existent when there are lots of starspots or tidal forces, but we’re not sure.

Want more? Here is the talk I gave for the “Three Minute Thesis” Competition held recently at my university. While I didn’t win, I thought I did pretty well. My classmate Kyle Uckert took home first place for his outstanding talk about searching for microbial life on other worlds. I had a lot of fun, though, and I learned how challenging it is for me to give a talk without visual cues (like multiple slides) and a strict time limit.

My slide for the Three Minute Thesis Competition. Image credits: G Perez, IAC, SMM (left), NASA (right), J Orosz (right)

Have you heard about how we’ve found over 1000 planets orbiting distant stars?

The Kepler space telescope finds planets by staring at stars. When a planet passes in front of a star, we see less light. This technique lets us not only DETECT planets, but also characterize them. For instance, a big planet will block more light than a small one.

OK, so, planets are great, but that’s not what my thesis is about. I study stars! It turns out that Kepler is also incredibly useful when the situation is a little different: instead of a planet orbiting a star, you have two stars orbiting each other.

Just by observing how the brightness changes with time, we can learn a lot of things about these binary stars, such as how long it takes for them to go around once and how much hotter one is than the other.

But Kepler alone doesn’t give us the full picture. For that, I use a telescope right here in New Mexico, at Apache Point Observatory, which spreads out all the different colors of light into a rainbow. I watch characteristic dark areas move from red to blue and back again, which tells me the velocities of the stars as they orbit. I then use that information together with the data from Kepler to get sizes, masses, and other properties for both stars.

Now, let me step back for a moment and ask: why do we care? Well, stars are astronomers’ main tool. Unlike other sciences, we can’t interact with what we study. What we CAN do is carefully measure light. And virtually all of the light we see bouncing around the Universe started out deep inside a star. So wouldn’t it be nice if we could look deeper and study the interiors of stars?

As it turns out, many stars, including our Sun, have sound wave oscillations going on inside that we can observe as small changes in brightness. And just like earthquakes help us study the interior structure of the Earth, these STARquakes let us study the insides of stars. This is called asteroseismology.

Conveniently enough, some of the biggest stars oscillate slowly enough that our friend Kepler can see it. This includes Red Giants, the kind of star our Sun will become when it runs out of hydrogen fuel in a few billion years.

In fact, based on what we know about their insides, we think ALL Red Giant stars should have these starquakes. So, we were surprised when we found several Red Giants that DON’T.

The good news is, because these stars are in binaries, that makes them relatively easy to study. I’m looking at binary stars with Red Giants that DO oscillate, and comparing them to binary stars with Red Giants that DON’T. Along the way, I’m using the systems that DO oscillate as a way to check quantities like mass and size that we can get from both techniques.

My research uses observations of binary stars together with asteroseismology to learn how all stars live and evolve.