Space Weather

‘Space Weather’ is a term that describes space environment conditions, especially around the Earth. It involves a variety of Earth space responses to both electromagnetic radiation, and particle and magnetic field outputs from the Sun Solar photons determine the most basic properties of the Earth's upper atmosphere and ionosphere, while the particles and fields interact with Earth's own field to produce the magnetosphere and all of its associated phenomena. These couplings and their consequences can produce disturbed conditions that result when the Sun is active, including ionospheric disturbances and geomagnetic storms. Observations of the erupting solar corona and its manifestations in the space around the Earth have provided a good idea of how the different features of solar behavior, such as solar wind and interplanetary magnetic fields, or coronal mass ejections and flares, relate to terrestrial responses such as auroras and induced ground currents. Practical applications of space weather knowledge include diagnosing the orbital decay and operational anomalies of Earth-orbiting spacecraft, and satellite-enabled communications and navigation problems. Studies of space weather also provide insights and context for interpreting observations of less-accessible planetary and extrasolar planet–star interactions contributing to the larger perspective on these important connections.