Heliophysics Overview

Heliophysics is the study of the Sun, and how it influences the very nature of space — and, in turn, the atmospheres of planets and the technology that exists there. Space is not, as is often believed, completely empty; instead, we live in the extended atmosphere of an active star. Our Sun sends out a steady outpouring of particles and energy -- the solar wind – as well as a constantly writhing magnetic system. This extensive, dynamic solar atmosphere surrounds the Sun, Earth, the planets, and extends far out into the solar system.

Studying this system not only helps us understand fundamental information about how the universe works, but also helps protect our technology and astronauts in space. NASA seeks knowledge of near-Earth space, because -- when extreme -- space weather can interfere with our communications, satellites and power grids. The study of the Sun and space can also teach us more about how stars contribute to the habitability of planets throughout the universe.

Mapping out this interconnected system requires a holistic study of the Sun’s influence on space, Earth and other planets.  NASA has a fleet of spacecraft strategically placed throughout our heliosphere -- from Parker Solar Probe at the Sun observing the very start of the solar wind, to satellites around Earth, to the farthest human-made object, Voyager, which is sending back observations on interstellar space. Each mission is positioned at a critical, well-thought out vantage point to observe and understand the flow of energy and particles throughout the solar system -- all helping us untangle the effects of the star we live with. 

See https://www.nasa.gov/topics/solarsystem/index.html