Postdoc Spotlight: Planetary Geophysicist Miki Nakajima

Miki Nakajima
Wednesday, April 26, 2017 

Miki Nakajima was born and raised in a "small" town in Tokyo. It was unusual, she says, for Japanese people (especially women) to study and work in the US long-term. But ever since she was in junior high she wanted to be a scientist. During her undergrad at the Tokyo Institute of Technology, she decided to major in Earth and planetary sciences, partly because it was something she could touch, imagine, and draw, but also because she would get the opportunity to travel to the US if she majored in it. A trip to Stanford? The Grand Canyon? Zion National Park? Las Vegas? She couldn’t turn that down! But what she once was told was unusual soon became reality. After completing her Ph.D. in planetary science at the California Institute of Technology, Nakajima became a postdoctoral fellow at DTM. Today, she is doing interdisciplinary work building theoretical models alongside world-renown experts while mentoring and encouraging the next generation of Japanese students to break out of their shells and explore new worlds, just like she did.

We talked to Nakajima about what research projects she’s currently working on, the research she hopes to do in the future, and more, in our latest Postdoc Spotlight.

Miki Nakajima with the James Webb Space Telescope (JWST) at NASA Goddard, and it will be launched next year. She is very much looking forward to its future observations! Photo courtesy of Miki Nakajima, DTM.

DTM: When did you first become interested in your field of research? Why?

Miki Nakajima: In junior high, I thought I would like to be a scientist because I realized that figuring something out was quite fun. During my undergrad, I was deciding whether I wanted to major in physics or Earth and planetary sciences. I decided to go with EPS, partly because professors in EPS seemed to be having a great time. Mostly, though, I liked something that I could touch, imagine, and draw, and I thought studying planets would be perfect. In addition, I would get to go on a field trip to the US if I majored in EPS, which also affected my decision to some extent (we went to Grand Canyon, Zion, Stanford campus, Las Vegas, and so on—it was fun!).

DTM: How did you first hear about DTM? What brought you here?

Nakajima: I had heard about DTM for years, but I got to know more about it when Lindy Elkins-Tanton became the director. I also realized that a number of exceptional scientists have been affiliated with DTM and GL and I thought it would be a wonderful place to work at (and I was right!). It is my great honor to be part of this community.

DTM: What excites you about your work?

Nakajima: My work is interdisciplinary, so it is really fun to always be learning new research topics in new fields. Carnegie has been a wonderful place for me because there are world experts in various research fields, such as planetary science, geophysics, geochemistry, geology, astronomy, astrophysics and so on. I also like having discussions on new ideas with my colleagues. Everyone is very helpful and cooperative, and I love this environment very much. Also, having beer hour and playing soccer after work is fun too.

DTM: What research projects are you working on now at DTM?

Nakajima: Fortunately, I have been working on so many interesting projects! In my Ph.D. thesis, I worked on the origin of the Earth and Moon based on a numerical method called Smoothed Particle Hydrodynamics (SPH) (some movies are listed here) to understand the initial states of the Earth and Moon. Now I am working with Erik Hauri on how much volatiles would have been present when the Moon formed. Also, Peter van Keken and I have been working on the evolution of the Earth's mantle over time. In addition to DTM scientists, I am collaborating with Robin Canup at Southwest Research Institute on the origin of the Martian moons, as well as with other exceptional scientists in the US, Europe, and Japan.

This is a numerical simulation based on the standard giant impact model (Hartmann and Davis 1975; Cameron and Ward 1976). A mars-size impactor hit the Earth, which created a debris disk around the planet. The Moon formed from the disk. Color scales with the entropy of forsterite in J/K/kg. This is the work of Nakajima, M. and Stevenson D.J. at Caltech. (related publications; Nakajima & Stevenson, 2014 and 2015)

DTM: What research do you hope to pursue at your next job?

Nakajima: I have been working on interdisciplinary research that connects various research fields, and I would like to continue to contribute this effort. Through my Ph.D., I mainly focused on developing and using SPH, but now I am learning new numerical skills and I would like to expand my horizons using those. I am very interested in developing models that can explain geochemical, geological, and astronomical observations, as well as make theoretical predictions for future space missions.

DTM: Where do you see yourself in 20 years?

Nakajima: I hope to enjoy science with a nice personal life. Fortunately, science is making progress day-by-day and it is almost impossible to make long-term future science plans. But of course, space missions require long-term planning -- and recently I started being involved in a space mission that is supposed to bring a sample back from a Martian moon Phobos (the Martian Moons eXploration mission, or MMX). It is scheduled to launch in 2024, and now we are now trying to predict what materials we would obtain. We are hoping that our model and the sample would constrain the origin of the moons.

Nakajima with the proto-Earth and an impactor that hit the Earth and formed the Moon (taken at NASA Goddard). It's been still a big mystery how the Moon got there. Photo courtesy of Miki Nakajima, DTM.

DTM: If you could meet one science icon, dead or alive, who would it be and why?

Nakajima: I really wish I had a chance to see Vera Rubin. Her scientific achievements were phenomenal, and I highly appreciate her extraordinary contributions to gender equality in science. I attended her memorial service hosted by DTM, and I was so touched by hearing wonderful stories about her. She has been and will be with us at all times.

DTM: Any other interesting anecdotes about your life or career you want to share?

Nakajima: I was born and grew up in a "small” town (the population is ~100k) in Tokyo and did not ever imagine that I would become a scientist working in the US because it is quite unusual for Japanese people, especially for women, to study and work in the US long term. I really like the environment here where you are encouraged to express yourself freely and suggest (occasionally) crazy ideas. I am really hoping that more and more Japanese students will come out of their shells and explore new worlds. I have been involved in activities, such as giving seminars to Japanese students in the US and Japan and joining science activities via Skype with elementary school students in Japan. I am hoping to encourage Japanese students to study abroad and I would like to continue my efforts doing that.

Miki Nakajima
Personal Website

Interview by Robin Dienel // April 26, 2017

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