Spectacular auroras renewed interest in geomagnetic storms — bursts of charged particles and magnetic fields, often from coronal mass ejections (CMEs) — that produce the northern lights. CMEs can travel through the solar system and, when they interact with Earth's magnetic field, drive auroras and disrupt electronics, satellites and radio systems. Space weather forecasting trails terrestrial meteorology by decades, though recent U.S. satellites since 2017 are improving observations. A very large solar storm could one day cause widespread technological disruption, so better monitoring and preparedness are important.
Ask a Met: What We Really Know About Space Weather — Auroras, CMEs and Risks to Technology
Spectacular auroras renewed interest in geomagnetic storms — bursts of charged particles and magnetic fields, often from coronal mass ejections (CMEs) — that produce the northern lights. CMEs can travel through the solar system and, when they interact with Earth's magnetic field, drive auroras and disrupt electronics, satellites and radio systems. Space weather forecasting trails terrestrial meteorology by decades, though recent U.S. satellites since 2017 are improving observations. A very large solar storm could one day cause widespread technological disruption, so better monitoring and preparedness are important.
06:21 PM, 11/15/2025Science
Ask a Met: What Do We Actually Know About Space Weather?
Spectacular auroras this week prompted a closer look at the geomagnetic storms that create the northern lights. Normally this column answers reader questions, but seeing those displays made me ask directly: what do we really understand about weather in space?
Meteorologist Jonathan Belles: Space doesn't have rain or snow, so the word "storm" means something quite different out there. We're talking about disturbances in plasma, particles and magnetic fields rather than precipitation.
The sun constantly emits light and streams of electrically charged particles — the solar wind — along with magnetic fields. A common source of intense space weather is a coronal mass ejection (CME): a huge eruption of plasma and magnetic field from the sun that can travel through the solar system. Some CMEs are powerful enough to travel far beyond the orbit of Pluto.
How CMEs affect Earth
When a CME reaches Earth's vicinity, its magnetic field can interact with Earth's magnetic field. That interaction funnels charged particles toward the polar regions, exciting atoms in the upper atmosphere and producing the colorful auroras. Most of the energy and particles are deflected, trapped, or redirected by Earth's magnetic field, but some reach the upper atmosphere and ionosphere where they cause visible displays and can alter electrical and radio environments.
Why space weather matters
Strong solar storms can interfere with satellites, GPS signals, radio communications, and power grids. Modern life relies heavily on technologies that are vulnerable to intense space-weather events, so identifying and forecasting major eruptions is important for mitigation and preparedness.
Forecasting: still catching up
Space weather science lags terrestrial meteorology by several decades in research, observations, and forecasting capability — roughly 50–60 years, by many estimates. Observational capacity is improving: the U.S. has launched multiple solar-observing satellites in recent years (including at least three operating since 2017) to better monitor the sun and give earlier warning of potentially dangerous eruptions.
That said, long-term forecasts remain imperfect. Scientists warn that a sufficiently large solar storm could one day cause widespread technological disruptions — not likely tomorrow, but possible on a timescale of years to centuries. Preparing infrastructure and improving forecasting tools are key to reducing that risk.
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