Summary of "What Is Space Weather?"

Space weather is the Sun’s “weather”: outflows and eruptions of hot, electrically charged gas and magnetic fields that travel through space and can affect Earth.

Space weather — overview

Space weather encompasses the continuous and transient streams of charged particles and magnetic fields emitted by the Sun. These phenomena travel through the solar system and interact with planetary magnetic fields and atmospheres, producing effects ranging from beautiful auroras to disruption of technological systems.

Solar wind

The solar wind is the constant flow of charged particles (plasma) from the Sun.
It continuously interacts with Earth’s magnetic field and shapes the near-Earth space environment.

Interaction with Earth

Charged particles are guided by Earth’s magnetic field toward the polar regions.
Collisions between those particles and atmospheric oxygen and nitrogen produce auroras:
- Aurora Borealis in the Northern Hemisphere and Aurora Australis in the Southern Hemisphere.
- Visible as green and red glowing curtains, depending on the species and altitude of the emitting atoms and molecules.
Earth’s magnetic field and atmosphere provide most of our protection from the solar wind and energetic particles.

Transient solar events

Solar flares and coronal mass ejections (CMEs) are sudden, intense releases from the Sun that can include:
- X‑rays
- High‑energy charged particles
- Large magnetic field structures
When these events reach Earth, they can:
- Disrupt radio communications
- Damage or degrade satellites
- Induce currents in power grids that can lead to electrical outages

Monitoring and forecasting (methodology and mitigation)

Satellites such as the GOES (Geostationary Operational Environmental Satellite) series carry instruments like the Solar X‑ray Imager to detect increases in solar X‑rays and energetic particles.
Space weather forecasters (for example, at the Space Weather Prediction Center) analyze satellite observations and issue alerts and warnings.
Early detection by instruments (e.g., GOES‑R series) provides lead time for power companies, satellite operators, and other stakeholders to take protective actions.