Will NASA’s Dragonfly Mission Encounter Dust Devils on Titan?

Dust Devils on Titan

Brian Jackson, Ralph D. Lorenz, Jason W. Barnes, and Michelle Szurgot

Summarized by Lisette Melendez

What data were used? In 2019, NASA announced a brand-new mission: Dragonfly. The objective? To visit Titan, the largest moon of Saturn and the only place in our universe (besides Earth) where distinct evidence of surface liquid has been discovered. Titan’s environment is very similar to that of very early Earth, with a nitrogen-rich atmosphere and volcanic activity. By studying Titan’s chemistry, scientists can discover more about the origin of life itself. It’s a very exciting mission, but it’s important for scientists to prepare for all the different obstacles the rotorcraft will encounter on Titan’s surface, including hazardous weather phenomena like dust devils.

An illustration of NASA’s Dragonfly rotorcraft-lander approaching the dunes on Saturn’s exotic moon: Titan. Credits: NASA/JHU-APL

We’ve learned more about weather patterns on Titan through NASA’s Cassini spacecraft, which orbited Saturn from 2004 to 2017. This study focuses on how dust storms are identified on other celestial bodies and what implications they hold for the Dragonfly mission. Cassini identified three regional dust storms within the equator near the “Shangri-La” dune fields that were chosen as Dragonfly’s landing spot. The study of these dust storms in Titan’s unique environment (with clouds and rain of methane!) can help us learn more about how they operate and life dust in the first place. This study also draws from observations by the Huygens probe for information on Titan’s temperatures and atmosphere.

Methods: In order to determine the weather conditions necessary for a dust storm on Titan, scientists need data on various atmospheric circumstances, such as temperature, elevation, and pressure. By analyzing the images and observations collected by Cassini and Huygens and combining these findings with data collected by observing dust devils here on Earth, scientists were able to model the surface conditions that were suitable for dust devil formation as well as the size of these storms. The study focused on dust devils on the equator because that’s where we have the most data available about Titan’s weather conditions.

An illustration of the Cassini-Huygens space-research mission, which was a collaboration between NASA, the European Space Agency (ESA), and the Italian Space Agency (ISA) to study Saturn and its many moons. Credit: NASA/JPL

Results: Many of the atmosphere conditions identified on Titan are favorable for the formation of dust devils. On Earth, dust devils are generally hindered by the presence of liquid because the increased particle cohesion (i.e., how sticky the particles are to one another) prevents wind from being able to lift the dust particles. Observations show that the equator of Titan is very arid and dry, with methane downpours only occurring in areas once every 10 Earth years. By looking at surface humidity levels measured by Huygens, it shows that the surface is too dry for even cloud formation. The abundance of dunes and dust storms provides further evidence that Titan has the ideal environment for dust devils.

An image of a dust devil in Kansas. Credit: The Thunderbolts Project

However, there are some surface conditions on Titan that may reduce the occurrence of dust devils, including the possibility of insufficient wind speeds. Additional work is required to model typical speeds on Titan’s surface.

Why is this study important? This study is important because it helps predict the occurrence of dust devils on Titan when Dragonfly is scheduled to arrive in 2034. This study outlines what remains unknown about the formation of dust devils and how Dragonfly presents the opportunity to study wind-related phenomena in a novel environment.

The big picture: After analyzing the environment on the surface of Titan based on the data currently available, it is concluded that the dust devils will most likely not pose a threat to the Dragonfly rovercraft (since they are too slow in the given conditions). Nevertheless, the mission can provide crucial insight to the creation of dust devils and how frequently they occur on other celestial bodies. Dragonfly provides us the opportunity to learn so much more about extraterrestrial worlds, and we’re all very excited for its departure!

Citation: Jackson, B., Lorenz, R. D., Barnes, J.W., & Szurgot, M. (2020). Dust devils on Titan. Journal of Geophysical Research: Planets, 125, e2019JE006238. https://doi.org/10.1029/2019JE006238

A First to Remember

Hello, it’s Lisette, a geology student who’s had the honor to take multiple classes with Dr. Sheffield!

I would like to talk about my summer undergraduate research experience through the Leadership Alliance at the Department of Earth and Planetary Sciences at Brown University. The program itself is called the Summer Research – Early Identification Program, and it was the first REU that I’ve ever applied to, and it really was a summer to remember! By the end of this article, I hope to convey why the Leadership Alliance is an amazing program that professors should encourage undergraduate students, especially those from underrepresented minorities, who have an interest in research to apply!

Scenery around Brown University.

So, what is the program exactly? The SR-EIP serves as an opportunity for undergraduate students to conduct research at an academic institution and receive career mentoring simultaneously in order to curtail the shortage of underrepresented minority groups earning PhDs. During my first week in the program, I attended various seminars that stressed the importance of diversity in STEM as well as coached us on the leadership skills necessary to advance in any field one pursues. We met and learned the stories of some truly amazing women in the STEM field, including Dr. Medeva Ghee, the executive director of the Leadership Alliance. She told us about how she was the first woman to intern at a company she applied for during her undergraduate career and how this spurred her drive to make science a more inclusive discipline for everyone. These workshops would continue throughout my stay at Brown twice a week during group meetings and after weekly dinners. My particular favorite was the one where a group of graduate students and professors at Brown discussed their afflictions of imposter syndrome because it was such a relief to know I wasn’t the only one who felt that way.

On the first day, I met the professor who was going to guide me on my first research experience, Dr. Mustard, as well as the graduate student who was there to support me: Alyssa Pascuzzo. They were monumental during my summer because they offered endless support and encouragement. Dr. Mustard continually checked up on my progress and was always excited to hear about the new skills I had learned. We also had weekly meetings where we would go over scientific articles about the polar caps of Mars and he would teach me more about the world of academia, including how to make the most out of conferences and the various paths one can take to land a career in research.

Presenting at my first research conference.

In tandem, I cannot overstate how important and motivational Alyssa Pascuzzo was throughout the summer and beyond! Every single day she was there with me, guiding me throughout the research process but still allowing me the freedom to choose my own project and how to go about it. She taught me how to use ArcGIS and MATLAB and showed me resources on how to become more proficient at both. I really appreciated how she would take the time to send me even more scientific articles about what I was studying and made sure to go over them afterwards for clarity and understanding. She also served as a grounding friend in a completely new environment and was always there for advice and encouragement. She helped me create my first research poster and stayed late to help me practice my presentation for the Leadership Alliance National Symposium. Even now, longer after summer has passed, she still serves as an exceptional mentor. And I think that’s what makes the Leadership Alliance such a great program for underrepresented students: it truly fosters a sense of community and belonging in those just starting their path in the intimidating yet exciting world of research. You have the opportunity to make so many long-lasting connections with people both inside and outside of your field of interest, and all of the members are open and thrilled to help you make the most of your experience.

If you know any undergraduate student (or are one yourself!) who has expressed interest in research, I sincerely hope you encourage them to apply for the Leadership Alliance. Their program covers a wide range of research areas (including humanities and social sciences through the Leadership Alliance Mellon Initiative) and builds a strong network of mentors that one has for life. We can aid in the diversification of the research workforce together!

 

Recently excavated human skulls provide insight into human migration from Southeast Asia to Australia

Somewhere beyond the sea: Human cranial remains from the Lesser Sunda Islands (Alor Island, Indonesia) provide insights on Late Pleistocene peopling of Island Southeast Asia

Sofía C. Samper Carro, Felicity Gilbert, David Bulbeck, Sue O’Connor, Julien Louys, Nigel Spooner, Danielle Questiaux, Lee Arnold, Gilbert Price, Rachel Wood, Mahirta

Summarized by: Lisette E. Melendez. Lisette Melendez is a geology major and astronomy minor at The University of South Florida. She is currently a junior, but has her sights set on going to graduate school for planetary Geology. She loves rocks, space, and everything pink.

What data were used? Newly excavated human remains from three test pits in Tron Bon Lei
(Wallacean Islands, Indonesia) are being compared to human remains from Asia and Australia to test for similarities. Other elements that were found in the excavation include shellfish, fish remains, and fish hooks were used to characterize the living environment.

Methods: This study used dating of various elements and observation of skull traits to estimate ages of the cranial remains. The first element studied was the amount of carbon- 14 in the specimen because carbon-14 can date items up to approximately 50,000 years old. Uranium and Thorium are both elements that are preserved in fossilized teeth and those elements were also measured to reinforce the reliability of the age estimates from carbon. Physical traits of the skull fragments were analyzed to estimate the age and sex of the samples. Age estimation was based on how worn down the teeth were and degree of cranial suture closure (tissues that fuse together as you get older).

The human remains recovered from Tron Bon Lei (Wallacean Islands, Indonesia).

Results: The dating measurements of these Wallacean specimens suggest that the skeletons were buried around 11.5 to 13 thousand years ago, at the end of the Pleistocene Epoch. They are smaller than any of the other cranial remains from Indonesia, Australia, and New Guinea, but the small size of these remains are similar in size to Holocene- age remains, supporting the model that southeastern Indonesian populations were isolated.

Why is this study important? This study helps us unravel the environment of southeast Asia and understand living conditions thousands of years ago.

The big picture: This study shows that the Wallacean islands may be an example of island dwarfing, suggesting that these populations may have been relatively isolated, at least up to the late Pleistocene. Island dwarfing typically occurs when there is a scarce amount of resources on an island, which was only exacerbated by the genetic isolation that occurred on this island.

Citation: Samper Carro, S. C. et al. Somewhere beyond the sea: Human cranial remains from the LesserSunda Islands (Alor Island, Indonesia) provide insights on Late Pleistocene peopling of Island Southeast Asia. J. Hum. Evol. 134, 102638 (2019). Online.