Solar and Space Physics for the Nation: An Overview of the 2024–2033 Decadal Survey (2025)
Chapter: Solar and Space Physics: Unlocking the Secrets of Our Local Cosmos
Solar and Space Physics: Unlocking the Secrets of Our Local Cosmos
For millennia, humans have gazed upon the Sun with reverence and wonder, and have been captivated by the shifting lights of the auroras—nature’s celestial displays. These enduring fascinations reflect a deeper drive to understand not only the forces that shape our skies but also our place in the vast and dynamic cosmos. Today, that drive fuels the field of solar and space physics in its quest to explore the heliosphere—the vast protective bubble formed by the solar wind that extends from the Sun to the outer fringes of the solar system, and beyond.
As humanity pushes toward becoming a spacefaring civilization—with plans for lunar bases and missions to Mars—our reliance on space-based and other technologies has also grown significantly. These systems, which support communication, navigation, power grids, and more, are vulnerable to disturbances from solar activity. Understanding and monitoring space weather is now essential for safeguarding both space missions and life on Earth. Recent advances in solar and space physics have revealed how solar activity and heliospheric conditions shape the near-Earth environment and influence habitability, transforming fundamental scientific discoveries into practical tools for predicting and mitigating space weather impacts.
“Humanity’s enduring curiosity about the universe propels exploration, and solar and space scientists have always been intrepid explorers.”
What Is the Heliosphere?
The solar wind—a continuous stream of charged particles from the Sun—creates and maintains the heliosphere, a vast “bubble” that extends far beyond the orbit of Pluto and defines the outer boundary of our solar system as it interacts with the interstellar medium. All the planets of the solar system, including Earth, are embedded deep inside the heliosphere. The heliosphere is a dynamic environment, constantly shaped by fluctuations in the solar wind, solar eruptions like coronal mass ejections, and the Sun’s 11-year activity cycle, all of which cause changes in its size, structure, and interaction with the surrounding interstellar medium.
The heliosphere defines the space environment of our home, Earth. Studying the heliosphere helps us understand how stars like our Sun influence the planets around them, which is essential for assessing the potential habitability of distant worlds—and it also advances our understanding of plasma—the hot, charged gas that makes up stars, the solar wind, and much of the visible universe.
Missions like NASA’s Parker Solar Probe and the Geospace Dynamics Constellation are delivering and planning to deliver unprecedented observations of how plasma behaves in the heliosphere and near-Earth space, revealing the physical processes that shape both our solar system and other astrophysical environments. This knowledge is also critical for protecting Earth’s technological infrastructure, as variations in space plasma can disrupt satellites, communications, navigation systems, and power grids—and it plays a vital role in ensuring the safety and sustainability of future human exploration of the Moon and Mars, where exposure to space weather and radiation is a significant challenge.
What Is Space Weather?
Space weather refers to conditions in space primarily driven by solar activity—such as solar flares and eruptions—that can affect the near-Earth environment. It is a critical area of applied solar and space physics with direct implications for national infrastructure and security.
While it can produce the stunning auroras seen near the poles, space weather can also disrupt satellites, interfere with communication and navigation systems, impact power grids, affect agriculture, and expose astronauts and high-altitude airline passengers to elevated radiation levels. It can cause widespread economic disruptions, with estimated costs reaching billions of dollars across affected industries. Continued investment in research, monitoring, and forecasting is essential to safeguard national assets and build resilience against these natural but potentially damaging phenomena.
Just as with Earth’s weather, accurate forecasting is key for managing space weather impacts. New technologies and techniques—such as helioseismology, which probes the Sun by observing the behavior of solar sound waves, much like seismologists study Earth’s interior using earthquakes—and machine learning are enhancing forecasting capabilities, potentially providing warnings hours to days in advance.
Recent Achievements
Scientific advances in solar and space physics over the past decade have led to remarkable discoveries throughout the heliosphere.
For the first time, a human-made object—the Parker Solar Probe—“touched” the Sun’s upper atmosphere, making exciting discoveries, including the occurrence of “magnetic switchbacks,” unexpected rotations of the solar magnetic field. The Voyager spacecraft, launched in 1977, made history when they crossed the heliopause—the boundary where the Sun’s influence ends and interstellar space begins—becoming the first human-made objects to leave the protective bubble of the heliosphere and enter the space between the stars.
Located atop the summit of Haleakalā on the island of Maui, Hawaii, the Inouye Solar Telescope features the largest primary mirror ever used in a solar telescope—measuring 4.24 meters (13.9 feet) across—along with advanced adaptive optics and cutting-edge imaging technology, enabling it to capture the highest-resolution images of the Sun ever recorded.
NASA’s Global-scale Observations of the Limb and Disk (GOLD) mission observed plasma bubbles in Earth’s upper atmosphere and enabled observations of the lower thermosphere temperature and composition, as well as the ionosphere, at an unprecedented temporal and spatial resolution.
NASA’s Solar Terrestrial Probes and Explorers programs have contributed several important missions over the past decade. For example, the Ionospheric Connection Explorer (ICON) mission, operational from October 2019 through November 2022, provided the first wide-scale quantification of the significance of atmosphere–ionosphere coupling mechanisms and revealed the importance of winds at 100–150 km altitudes in driving ionospheric variability.
Other missions continue to provide new scientific insights. Launched in 2015, NASA’s Magnetospheric Multiscale (MMS) mission remains active, and ongoing analysis of its data continues to advance the understanding of the microphysics of magnetic reconnection. Similarly, data from NASA’s Van Allen Probes—operational from 2012 to 2019—continues to
yield important new insights into wave-particle interactions in Earth’s radiation belts.
Space weather prediction has advanced significantly over the past decade, driven by improvements in numerical modeling, observational data, and computational power. Scientists can now simulate the complex dynamics of the space environment with greater accuracy than ever before. NOAA’s Space Weather Prediction Center uses these models to forecast geomagnetic activity and other space weather phenomena. Tools such as the Space Weather Modeling Framework support operational forecasting by integrating solar, heliospheric, and geospace conditions—providing critical insights and lead times of up to an hour before geomagnetic storms impact Earth.
Future Opportunities
Building on the investments of the past decades, the next decade brings tremendous opportunities to enrich our understanding of the space around us and prepare humanity for the future.
The decadal survey sets forth a two-part vision and mission for solar and space physics for the coming decade: research and exploration to discover the secrets of the local cosmos and applied science to expand and safeguard humanity’s home in space.
The first part of the mission reflects the curiosity-driven motivations for advancing solar and space physics research. The second part reflects the increasing importance of space weather for society. While these are two distinct and equally important reasons for investing in solar and space physics, they are integrally linked and have overlapping scientific goals; progress on one part of the mission invariably enables progress on the other.
The decadal survey provides a thematic roadmap to enrich understanding of the space around us and to prepare us for the future. Its bold vision can only be achieved through increased funding, a comprehensive research strategy, international collaboration, and the efforts of a thriving solar and space physics workforce.
