Big Questions for Heliophysics
Heliophysics is a new field of science — the determination of the mechanisms and processes of the solar system as driven by the Sun. NASA is working to study the big science questions to help us understand the complex behavior of the Sun to develop the capability to predict changes to Earth and its space environment. A collection of spacecraft, the Heliophysical Great Observatory, patrols the expanse from the Sun to the frontiers of the solar system and beyond. This observatory reveals not a placid star and isolated planets, but an immense, dynamic, interconnected system of which our home planet is part and through which space explorers must journey.
- How does solar variability affect human society, technological systems and the habitability of planets?
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Geomagnetic storms (magnetic storms on Earth due to solar activity) produce the awe-inspiring Aurora borealis and Aurora australis -- the Northern and Southern lights. However, they can also cause a variety of highly undesirable consequences. Electrical current surges in power lines, interference in the broadcast of radio, television, and telephone signals, and problems with defense communications are all associated with magnetic storms.
- What are the hazards and resources in the Solar System environment that will affect the extension of human presence in space?
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Harsh conditions in the space environment pose significant risks for the journey of exploration. Although space is a near-vacuum, the very-thinly-spread particles and fields are like an ocean that can affect the spacecraft and astronauts that travel through it. Like seafaring voyagers, space explorers must be constantly aware of the current space weather and be prepared to handle the most extreme conditions that might be encountered.
- How and why does the Sun vary and what are the consequences?
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The Sun varies in every way we can observe it. The Sun give off light in the infrared, visible, ultraviolet, and at x-ray energies, and it gives off magnetic field, bulk plasma (the solar wind) and energetic particles moving up to nearly the speed of light, and all of these emissions vary. These variations occur on timescales from fractions of a second to hundreds of years and longer.
- What are the fundamental physical processes of the space environment?
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The sun, interplanetary space, planetary magnetospheres, and most of the rest of the universe are made up of plasma, which is an electrically-charged gas. Because they are plasma, electro-magnetic forces are extremely important. There is a tight coupling between the matter (in the form of sub-atomic particles) and the electric and magnetic fields. Motion of plasma in the sun generates the solar magnetic field, and the magnetic stresses built up are what cause the sun to vary. Magnetic reconnection, a rapid reconfiguration of the magnetic field, can accelerate matter up to very high energies and make hazardous radiation. Other more gradual processes can also accelerate particles up to hazardous energies. Understand the intricate interplay between matter and electro-magnetism in the space environment is what requires a system-level study that we call Heliophysics.