First Billion Years of Solar System History (planet formation/emergence of life)

What processes marked the initial stages of planet and satellite formation?

What was the nature of Jupiter’s formation, and how different was it from that of Neptune, Uranus, and Saturn?

How did the impactor flux decay in the early solar system, and how did this affect the timing of the emergence of life on Earth?

Volatiles and Organics: The Stuff of Life (organic materials, water, etc.)

What is the history of volatile compounds, especially water, in the solar system?

What is the nature of organic material in the solar system and how has it evolved?

What global mechanisms affect the evolution of volatiles on planets?

The Origin and Evolution of Habitable Worlds

What planetary processes generate and sustain habitable worlds, and where are the habitable zones in the solar system?

Does (or did) life exist beyond Earth?

Why have the terrestrial planets differed so dramatically in their evolution?

What hazards do solar system objects present to Earth’s biosphere?

Processes: How Planets Work

How do processes that shape the character of planets operate and interact?

What does the solar system tell us about the development of extrasolar planetary systems, and vice versa?


  1. Understanding the structure and dynamics of the Sun’s interior, the generation of solar magnetic fields, the origin of the solar cycle, the causes of solar activity, and the structure and dynamics of the corona. Why does solar activity vary in a regular 11-year cycle? Why is the solar corona several thousand times hotter than its underlying visible surface, and how is the supersonic solar wind produced?

  2. Understanding heliospheric structure, the distribution of magnetic fields and matter throughout the solar system, and the interaction of the solar atmosphere with the local interstellar medium. What is the nature of the interstellar medium, and how does the heliosphere interact with it? How do energetic solar events propagate through the heliosphere?

  3. Understanding the space environments of Earth and other solar system bodies and their dynamical response to external and internal influences. How does Earth’s global space environment respond to solar variations? What are the roles of planetary ionospheres, planetary rotation, and internal


National Research Council, New Frontiers in the Solar System: An Integrated Exploration Strategy, National Academy Press, Washington, D.C., 2002.


National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, National Academy Press, Washington, D.C., 2002.

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