Big Questions for Explorers
- 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.
- How do planets, stars, galaxies and cosmic structure come into being?
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In order to understand how the Universe has changed from its initial simple state following the Big Bang (only cooling elementary particles like protons and electrons) into the magnificent Universe we see as we look at the night sky, we must understand how stars, galaxies and planets are formed.
- When and how did the elements of life in the Universe arise?
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Following the Big Bang and the gradual cooling of the Universe the primary constituents of the cosmos were the elements hydrogen and helium. Even today, these two elements make up 98% of the visible matter in the Universe. Nevertheless, our world and everything it contains—even life itself—is possible only because of the existence of heavier elements such as carbon, nitrogen, oxygen, silicon, iron, and many, many others. How long did it take the first generations of stars to seed our Universe with the heavy elements we see on Earth today? When in the history of the Universe was there a sufficient supply of heavy elements to allow the formation of prebiotic molecules and terrestrial-like planets upon which those molecules might combine to form life.
- 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 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.
- 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 origin, evolution and fate of the Universe?
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Two of the most profound questions that all cultures, both past and present, have asked are: where did we come from and what is our destiny? Throughout history philosophers, theologians, and scientists have debated these questions. NASA Science seeks to provide quantitative information pertinent to these basic elements of human curiosity by enabling scientists and engineers to construct instruments and make measurements on these topics that were once the purview of thought experiments only.