oscillating chemistry in zero gravity and beyond
(From motivation to long-term vision to immediate objective)
(From motivation to long-term vision to immediate objective)
How did life originate? Nobody knows. Life might not even be native to our Earth - it might have come from asteroids or the interstellar medium. While pioneering laboratory studies recently made progress for prebiotic (origin-of-life) chemistry, the question arises whether such reactions would also work in zero- or hypergravity environments.
With Ø-scillation, we won't answer these big questions at once. Instead, we aim to contribute one more small step towards a future answer by prototyping and using a proxy reaction: how do zero- and hypergravity affect the reaction rates in oscillating reactions?
To this end, we develop a robust, compact, and simplified version of the Briggs-Rauscher experiment; an oscillating chemistry event often called the Iodine clock, which cycles through amber and blue colors. The hypothesis to be tested is that different gravity environments do not alter the reaction rates of the involved chemistry. If this can be confirmed, we might be able to add another tiny piece to the puzzle.
The 20-year vision behind this project is to leverage the expertise we gain and push forward one small step at a time. We aim to expand Ø-scillation into suborbital flights and ISS experiments, ultimately paving the way for cube satellite setups that can examine actual prebiotic chemistry in zero gravity.
Video 1: Ø-scillation on the Zero G parabolic flight. We finally flew our experiment in May 2021! You can also see me experiencing Marsian, Moon and zero-gravity environments.
Video 2: One full cycle of the Briggs-Rauscher reaction, changing color from blue to amber and back to blue within 20 seconds; hosted in our final setup.
How did life originate? (Motivation)
A short question, but one that has driven humankind for millennia. Still, nobody knows the answer. The beginning exploration of space and the rise of exoplanet science with its discovery of temperate worlds open up a new avenue in the search for the origin of life. Multidisciplinary research and pioneering laboratory studies have shown potential pathways for abiogenesis, forming precursors for RNA (e.g. Powner et al., 2009; Patel et al., 2015; Xu et al, 2018; Rimmer et al., 2018). But do the mechanisms working in a laboratory, and proposed to work on a young Earth, also work in more extreme environments?
What if life has not actually formed on Earth? Some theories postulate that life might have formed on asteroids, and was then distributed onto Earth (e.g. Ciesla & Sanford, 2012). Moreover, in our search for habitable exoplanets, one can wonder if and how life might have originated on very extreme planets - ones ranging from the size and low-gravity of the Moon to so called Super-Earths, that can have up to 8 times the surface gravity of our Earth.
What do we hope to contribute? (Long-term vision)
Our goal is to study if this Earth-bound prebiotic chemistry could also work in extreme environments ranging from zero G to multiple G, by investigating how altered gravity affects the mixing and reaction rates, accelerating or decelerating the chemistry. To answer this, we are designing a set of experiments to be conducted over the next 20 years which will help us to answer this question. In our first proposal in this long series, we want to make use of the unique opportunity provided by a parabolic flight, which will let us experience a fluent variation of gravity environments from hyper- to zero-gravity and back. In doing so, we will build up on and expand the scope of previous experiments (e.g., Fujieda et al., 1996, 1999 and many others).
What is our goal here? (Immediate objective)
Ø-scillation serves both as a technical prototype and a science experiment.
In this study, we develop a robust, compact, and simplified version of the Briggs-Rauscher experiment, an oscillating chemistry event often called the Iodine clock. The hypothesis to be tested is that different gravity environments do not change the reaction rates of this oscillating chemistry experiment. Starting from three main components Potassium Iodate, Hydrogen Peroxide and Starch, the reaction changes color from blue to amber in a cyclic way. Each color cycle takes about 20 seconds, and a total of 5-10 cycles are completed. The full experiment runs for about 2-3 minutes. See Video 1 and Schematic 1 for one cycle of the reaction and Figs. 1-3 for the technical drawings and final assembly.
In the parabolic flight, we experimentally measure the reaction rates by monitoring the color change over all 5-10 cycles while undergoing 2-3 flight parabolas. We record the color change using optical video cameras, mounted onto the experimental setup (Fig. 3). In the post-flight analysis, we extract the color information from each video pixel, and record a time series of the color expression. We also mount a TerMITe sensor on the setup, which record the 3D acceleration, temperature, pressure, and more during flight (Fig. 4). We then cross-correlate the color-change time series with the TerMITe's accelerometer data (Fig. 5).
Our experimental setup allows for 4 simultaneous experiments, allowing us to assess any intrinsic variance of the reaction. Finally, we compare the outcome of the flight experiments with our ground-based studies (conducted at Earth gravity), investigating whether any significant changes have occurred. Going forward, we additionally aim to assess the dependency of hypergravity environments in centrifuge setups.
Figure 1: The full design, with the acrylic block at its center, the mounting stage and camera above, and everything eluminated by an LED strip. Credit: Maximilian N. Günther
Schematic 1: the steps taking part during the Briggs-Rauscher reaction.
Figure 2: The CAD modeling and resulting design drawing for the clear acrylic block. Hosting the Petri dishes and syringes, this is the heart of the setup. Credit: Maximilian N. Günther, Joel Villaseñor, Richard Hall
Figure 4: A TERMITES sensor, which we will use to monitor the 3D acceleration, temperature, pressure, and more during flight. Credit: Carson Smuts
Figure 5: Example of TERMITES data taken with termites on a Zero G flight in 2018. The orange curve shows the acceleration in z-direction, reflecting the gravity experienced during the parabolas. Credit: Carson Smuts
Maximilian N. Günther, with (alphabetical order) Matt Carney, Juliana Cherston, Maggie Cobletz, Ariel Ekblaw, Natalia Guerrero, Richard Hall, Corinna Kufner, Xin Liu, Janusz Petkowski, Sukrit Ranjan, Paul Rimmer, Jessica Santivañéz, Dimitar Sasselov, Sara Seager, Clara Sousa-Silva, Carson Smuts, Valentina Sumini, Zoe R. Todd, Joel Villaseñor
Ciesla, F. J., & Sandford, S. A. (2012). Organic Synthesis via Irradiation and Warming of Ice Grains in the Solar Nebula. Science, 336(6080), 452 LP – 454. https://doi.org/10.1126/science.1217291
Fujieda, S., Mogami, Y. Zhang, W., & Araiso, T. (1996). Instrumental Achievements Experimental System Assembled for Studying the Chemical Oscillation Behavior of Belousov-Zhabotinskii Reactions in the Microgravity. Analytical Sciences, 12(5), 815–818. https://doi.org/10.2116/analsci.12.815
Fujieda, S., Mogami, Y., Moriyasu, K., & Mori, Y. (1999). Nonequilibrium / nonlinear chemical oscillation in the virtual absence of gravity. Advances in Space Research, 23(12), 2057–2063. https://doi.org/10.1016/S0273-1177(99)00163-5
Powner, M. W., Gerland, B., & Sutherland, J. D. (2009). Synthesis of activated pyrimidine ribonucleotides in prebiotically plausible conditions. Nature, 459(7244), 239–242. https://doi.org/10.1038/nature08013
Patel, B. H., Percivalle, C., Ritson, D. J., Duffy, C. D., & Sutherland, J. D. (2015). Common origins of RNA, protein and lipid precursors in a cyanosulfidic protometabolism. Nature Chemistry, 7(4), 301–307. https://doi.org/10.1038/nchem.2202
Rimmer, P. B., Xu, J., Thompson, S. J., Gillen, E., Sutherland, J. D., & Queloz, D. (2018). The origin of RNA precursors on exoplanets. Science Advances, 4, eaar3302. https://doi.org/10.1126/sciadv.aar3302
Xu, J., Ritson, D. J., Ranjan, S., Todd, Z. R., Sasselov, D. D., & Sutherland, J. D. (2018). Photochemical reductive homologation of hydrogen cyanide using sulfite and ferrocyanide. Chemical Communications, 54(44), 5566–5569.