Meet the AAS Keynote Speakers: Dr. Giada Arney

In this series of posts, we sit down with a few of the keynote speakers of the 245th AAS meeting to learn more about them and their research. You can see a full schedule of their talks here, and read our other interviews here!


When I saw Dr. Giada Arney is an astrobiologist, the first interview question that popped into my head was to ask if she believes in aliens. I didn’t ask her this, because I can only assume that’s the first thing literally everyone asks her when they find out her job. From the title of her plenary talk, Are We Alone? The Search for Life on Habitable Worlds, we might just get an answer at AAS 245. 

As a planetary scientist and astrobiologist at NASA, Dr. Arney studies exoplanets and their biosignatures. Biosignatures is a broad term for chemical observations that can’t be explained by non-life processes. This makes them a very broad way to quantify what life can look like in the Universe; astrobiologists don’t want to just look for signatures of Earth-like life. These biosignatures come from spectra taken of planets that pass in front of the face of their star (called transit spectroscopy). As the light passes through the planet’s atmosphere, it will be absorbed and scattered, creating the ‘signature’ lines at specific wavelengths indicating which element it interacted with. By looking at the full spectra of many wavelengths, astrobiologists can pick out what elements are in the atmosphere and their relative abundances

Dr. Arney has always wanted to be an astronomer, and her career trajectory has “been a path to my dream job”. She received her Ph.D. in astronomy from the University of Washington in 2016. Her work there included observations of Venus’ atmosphere and using early Earth – the “Pale Orange Dot” due to atmospheric haze – as an exoplanet analog. After graduating she was a NASA postdoctoral fellow working on photochemical modeling of exoplanet atmospheres, and in 2017 became a civil servant scientist at Goddard. 

via AAS

The field of planetary science and astrobiology has exploded in the past decade, and the future is bright. Missions like K-2 and TESS have uncovered nearly 6,000 planets as of December 2024, with thousands of candidates waiting to be confirmed or killed. (That is the real, technical term that they use.) Upcoming projects like the DAVINCI and VERITAS missions to Venus are making strides in understanding our own solar system. Venus is specifically of interest for astrobiology because there is some suggestion that Venus used to be able to host life, although it can’t anymore. Understanding that transition between habitable to uninhabitable and the signatures of each is important for studying planets that we can’t actually send probes to (like those outside our solar system). 

The Habitable Worlds Observatory, for which Dr. Arney is the interim Project Scientist, is scheduled to launch in the early 2030’s. It’ll be the first mission specifically designed to directly image planets and will allow us to take incredibly detailed spectra of their atmospheres, possibly giving us the first evidence of biosignatures on other worlds. But not finding any signatures of life on nearby planets would be an equally interesting result, because it would allow astrobiologists to quantify just how rare our biosphere is. The kinds of biosignatures possible is also expanding, as the library of known chemical processes and their spectral signatures is expanding. There are thousands of possible spectral lines, and cataloguing all of them will be necessary to properly understand what we see in the atmospheres of other worlds. 

 Dr. Arney’s advice for very-early career researchers is to develop your communication skills. In particular, with interdisciplinary work like astrobiology, it’s super important to be an expert in your subfield and to be able to work with people who are experts in their subfields. You don’t have to know everything, you just have to know how to work with the people who can fill in the gaps.

Are We Alone? The Search for Life on Habitable Worlds is on Wednesday January 15 at 11:40 AM ET in Potomac Ballroom AB.


Edited by: Jessie Thwaites

Featured Image Credit: AAS

Author

  • Lindsey Gordon

    Lindsey Gordon is a fourth year Ph.D. candidate at the University of Minnesota. She works on AGN jets, radio relics, MHD simulations, and how to use AI to study all those things better.

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