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Space Environment and Planetary System Science Kanako Seki Laboratory

Space Environment and Planetary System Science
Kanako Seki Laboratory

Advancing the Frontier in Space:
Unraveling Space Weather and the Essential Conditions for Habitable Terrestrial Planets

The vast space surrounding us is a dynamic plasma world where space radiation flies about and plasma particles interact with each other in complex ways through electromagnetic field variations. The field of Space Environment and Planetary System Science has developed rapidly since the dawn of the space age. In our laboratory, we combine scientific satellite observations with our own numerical simulations/models to study universal plasma processes in universe, space weather phenomena that are becoming indispensable to modern society, and the effects of atmospheric escape on habitability of terrestrial planets.

Research on space weather phenomena on Earth, Mars, and beyond

“Space weather” refers to variable conditions on the Sun, throughout space, and in the planetary environment that can influence the performance and reliability of space-borne and ground-based technological systems and endanger human life and health. Phenomena related to the space weather include auroras and space radiation (high-energy particles) variations. Around Earth, we are conducting research through close collaboration between satellite observations by the geospace exploration satellite “Arase,” ground-based observations, and numerical simulations. The approach of the integrated studies that combines diverse data tailored to the scientific challenges we aim to address. The space environment surrounding a planet varies significantly depending on whether the planet possesses a global intrinsic magnetic field. As the frontier of the human exploration expands from the Moon to Mars, extending current Earth-based research into planetary space weather has become an urgent necessity. We participate also in Mars exploration missions such as NASA's MAVEN and JAXA’ s MMX. We combine these observations with our own numerical models to advance our understanding of planetary space weather phenomena such as Martian aurorae.

Research on space climate to understand the impact of stellar activities on planetary environments

An atmosphere is essential for maintaining a habitable surface environment with oceans like Earth. Understanding atmospheric escape to space, which determines the conditions for atmospheric retention, is one of the key issues in elucidating the recipe for a second Earth. In particular, understanding how various proposed atmospheric escape mechanisms depend on stellar activity and planetary magnetic field strength is key to elucidating the diversity and universality of terrestrial exoplanets. To address this issue, we have developed original numerical models that have been tested by observations of planets in our solar system and are beginning to apply them to exoplanets. For example, our recent studies have revealed that intense solar activity at that time may have caused significant atmospheric escape from ancient Mars, leading to the loss of most of its atmosphere and habitable environment. Our research has also shown that the presence of an intrinsic magnetic field can suppress atmospheric escape from Venus-like exoplanets, significantly extending their atmospheric retention (habitable) period. Additionally, we are conducting research on how space radiation interacting with the atmosphere influences the formation of prebiotic molecules based on photochemical models.

Installation of aurora observation cameras in Canada.

Global MHD simulation results of the interaction between the solar wind and ancient Mars. The lines and color code show magnetic field lines and atmospheric escape rates, respectively.

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My motto is, "If you learn without thinking, you cannot understand truly. If you think without learning, you will be self-righteous."This is a quote from Confucius in the Analects, emphasizing the importance of balancing learning and thinking. During my student days, I was conscious of the importance of not blindly accepting knowledge but rather thinking for myself. However, as my workload increased and I became busier with work, I found myself relying more on experience and intuition, leading to a tendency to prioritize thinking over learning. This can be particularly dangerous for researchers in the field of Space Environment and Planetary System Science, as we tackle uncharted territory/knowledge in deep space, where common ground rules may not apply.
Reflecting on this, I recently took on the role of Editor for an international academic journal at a time when my duties as an Aid to the University President had come to a conclusion. By immersing myself in an environment where I am constantly exposed to the latest knowledge and continue to learn, I have the opportunity to continuously question my own thinking. In the process of moving between learning and thinking, I feel the true joy of being a researcher when light begins to shed on previously unknown phenomena. I will continue to approach the mysteries of the universe with humility, striving to learn and think, and enjoy the challenge of exploring the unknown.