Meet the New Host of Ask Science

Dr. Lee Falin signs off and introduces the new host of Ask Science, astrophysicist Dr. Sabrina Stierwalt. Learn about how Dr. Stierwalt got interested in galaxies and her 3 tips for young people considering careers in science.

Sabrina Stierwalt, PhD
5-minute read
Episode #128

After nearly 3 years and 128 episodes, I've decided to pass the baton to a new host of Ask Science.

I'm so excited to introduce you to the new host of the Ask Science podcast: Dr. Sabrina Stierwalt!

Sabrina is an astrophysicist who studies far away galaxies. I sat down to talk to Sabrina about how she got interested in astrophysics, plus, what advice she has for young people considering careers as scientists:

Dr. Lee Falin: What kind of science do you do?

Dr. Sabrina Stierwalt: Thanks for the kind introduction Lee. I'm so happy to be here. 

I am an extragalactic astrophysicist, which means I research galaxies beyond our own to understand how they form and evolve. I want to know why some galaxies are very dynamic - readily forming stars and growing super massive black holes - while others are more passive and don’t seem to have changed much over most of the universe’s 14 billion year history.

Dr. Lee Falin: What first inspired you to pursue science as a career?

Dr. Sabrina Stierwalt: I didn’t really know that I wanted to be an astrophysicist until I was in college.  Before that, as a middle and high school student, I was always interested in math. It’s a universal language! The rules of math are always the same and I think that’s pretty powerful. Plus, I’ve always liked busting stereotypes, and I was the only girl on the math team.

Once I got to college, I realized that I wanted to apply that math knowledge to something, and after my first trip to an observatory, I was completely hooked on astronomy. There I was on top of a mountain with more stars overhead than I had ever seen in my life thanks to the lack of city lights. It also helped that I was looking through a multi-million dollar telescope pointing at the galaxies I had chosen to study.

M81 Galaxy. Image Credit: nasa.gov

I remember having to stand on a shaky ladder and lift a really heavy tank of liquid nitrogen - nitrogen that had been chilled to such a low temperature (-320o F) that it is a liquid instead of a gas. Astronomers filled tanks surrounding our detectors with liquid nitrogen to keep those detectors cold and to prevent any internal signals from popping up in our data that we may mistake for extragalactic sources. I almost dropped that tank multiple times because you can’t touch it without thick gloves. Since they weren’t accustomed to having women around, they only had enormous, man-sized gloves at the observatory, I wanted to run my own observations though, so I refused to ask for help. Eventually, I got it done.

Now a big part of my job as an astrophysicist is traveling all over the world to different telescopes to collect my data. I have visited telescopes in Australia, India, Chile, and even on top of a volcano in Hawaii.

Dr. Lee Falin: What's been your most surprising or inspiring discovery to date?

Dr. Sabrina Stierwalt: I do a lot of research on interacting galaxies - massive galaxies, like the Milky Way that we live in, that are colliding with each other. Did you know that one day the Milky Way and our nearest big galaxy neighbor, the Andromeda Galaxy, will collide? Lucky for us that day is far, far in the future, so there's no need to worry.

Galaxies are made up of stars, gas, and dust. When they collide, most of that material gets thrown into the center of the collision, called the center of mass of the system. When you have a bunch of gas and dust colliding, this in turn inspires intense bursts of star formation and eventually the growth of super massive black holes.

My collaborators and I recently found an incredibly dense starburst – an unusually high level of star formation in a very compact region in space – that was triggered by a collision between two massive galaxies. This is one of the most intense starbursts that astronomers have ever found. Using our knowledge of how stars form out of gas clouds, astronomers can predict how dense starbursts can really be. The starburst my team and I have found is surpassing some of these theoretical limits and making us rethink some of the current models.

To make this discovery I used a new telescope in the Chilean desert called ALMA or the Atacama Large Millimeter Array. ALMA is so sensitive that it can detect the trails left by Pluto-sized planets in the dust around other Sun-like stars in our galaxy. ALMA can also detect other galaxies that are so distant that the light they emitted when they were forming, only one billion years after the Big Bang, is just reaching us now. The “millimeter” in ALMA’s name emphasizes that the telescope looks at light with millimeter and sub-millimeter wavelengths, which includes wavelengths that we have never been able to see before because astronomers did not have the detector technology to do it.

If you want to learn more about cutting edge research that is pushing the forefront of our knowledge in astronomy, definitely keep an eye out for new discoveries coming from ALMA. I will be sure to report on any of these exciting discoveries on the Ask Science show.

Dr. Lee Falin: What advice do you have for young people who are interested in science?

Dr. Sabrina Stierwalt: I have 3 tips for young people who are interested in science and possibly pursuing careers as scientists.

Image Credit: nrao.edu

First, ask questions. The most important part of being a scientist is to look at the world around you, find something you don’t understand, and then try to figure it out. Every kind of scientist does this – biologists, chemists, as well as astrophysicists.  If you are in class, don’t hesitate to ask a question simply because you think you're the only one who doesn’t know the answer. Most likely, other students have the same question, or, if they don’t, they just may not have thought of it yet.

Second, learn to code. In the very near future, there are going to be a lot of jobs that require coding skills and knowing how to manipulate large amounts of data, but not enough people with the skills to fill them. If you can write a Python script or run an SQL query, you will have so many opportunities to pursue what interests you. Two easy ways for young people to start coding are the tutorials at code.org and the exciting program Girls Who Code.

Third, keep in mind that there are many ways to be a scientist. Scientists aren’t just men in lab coats. They can be. but they don’t have to be. They are doing field work in the jungle or at the bottom of the ocean. They are helping patients in hospitals. They are observing space with telescopes on top of volcanoes.

Science plays a role in everything that we do. Scientists launch spacecraft that land on comets, and they formulate your shampoo to give your hair the perfect amount of shine. I am a scientist, and you can be a scientist too.

I'm thrilled to be taking over the Ask Science podcast because I get to learn and discover our world along with you. 

Galaxy image courtesy of Nasa.gov.  ALMA image courtesy of nrao.edu.

Please note that archive episodes of this podcast may include references to Ask Science. Rights of Albert Einstein are used with permission of The Hebrew University of Jerusalem. Represented exclusively by Greenlight.

About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.