# Solar Wind
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Who / What
The **solar wind** is a continuous stream of charged particles—primarily electrons and protons, along with heavier ions like alpha particles—emitted from the Sun’s outermost atmospheric layer, the corona. These particles are superheated plasma with kinetic energies ranging from 0.5 to 10 keV, traveling outward through space at speeds of approximately **400–700 km/s** under the influence of solar magnetic fields.
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Background & History
The concept of the solar wind was first theorized in the early 20th century as scientists sought to explain phenomena like auroras and cosmic rays. The term itself was coined by **Eugene Parker**, an American astrophysicist, in his groundbreaking 1958 paper *"Dynamical Problems of Interplanetary Gas and Plasma."* Parker proposed that the Sun continuously ejects a supersonic plasma stream into space, later named after him. Early observations from spacecraft like **Mariner 2 (1962)** confirmed its existence by detecting charged particles escaping the solar system.
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Why Notable
The solar wind plays a critical role in shaping space weather and influencing planetary environments. Its interaction with Earth’s magnetosphere creates phenomena such as auroras, disrupts satellite communications, and poses risks to spacecraft electronics. Beyond Earth, it erodes atmospheres of Mars and other bodies, demonstrating its erosive power over cosmic timescales. Studying the solar wind also provides insights into stellar plasma physics and the dynamics of interplanetary space.
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In the News
Recent advancements in heliophysics have intensified interest in the solar wind due to its growing impact on modern technology. NASA’s **Parker Solar Probe (launched 2018)**, the fastest human-made object, is designed to study its origins and composition up close, offering unprecedented data on how the Sun drives space weather. Additionally, increasing concerns about geomagnetic storms—caused by solar wind disturbances—highlight its relevance for power grids, GPS systems, and satellite operations in an era of heightened digital dependency.
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Key Facts
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