What are solar flares and coronal mass ejections (CMEs)? Explain how they can cause radio blackouts on Earth

Recent warnings from ISRO about potential radio blackouts due to intense solar storms highlight a growing concern: our increasing vulnerability to space weather.

Published on Feb. 4, 2026

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The Sun's dynamic activity, including solar flares and coronal mass ejections (CMEs), can have significant impacts on Earth's technology and communication systems. Solar flares emit intense radiation that can ionize the ionosphere and disrupt high-frequency radio communications, while CMEs can trigger geomagnetic storms that damage satellites, strain power grids, and degrade GPS accuracy. Understanding these space weather phenomena and improving forecasting capabilities are crucial for mitigating the risks and harnessing the potential of solar activity.

Why it matters

As our reliance on space-based technology and infrastructure continues to grow, the need to understand and prepare for the effects of space weather becomes increasingly important. Solar flares and CMEs can have widespread and potentially catastrophic consequences, impacting everything from aviation and maritime communication to power grids and GPS-dependent systems. Improving our ability to predict and respond to these events is crucial for ensuring the resilience of modern society.

The details

Solar flares are sudden, intense bursts of radiation that travel at the speed of light, primarily impacting Earth's radio communications almost immediately. Coronal mass ejections (CMEs), on the other hand, are massive expulsions of plasma and magnetic field from the Sun's corona, taking 15 hours to several days to reach Earth but with a far more widespread and potentially disruptive impact. When CMEs arrive at Earth, they interact with the planet's magnetosphere and ionosphere, causing geomagnetic storms that can disrupt radio communications, damage satellites, strain power grids, and degrade GPS accuracy.

  • The 2003 Halloween storms caused significant damage to several satellites.
  • The 1989 Quebec blackout, caused by a geomagnetic storm, left six million people without power for nine hours.

The players

Indian Space Research Organisation (ISRO)

India's national space agency that has issued warnings about potential radio blackouts due to intense solar storms.

NOAA's Space Weather Prediction Center (SWPC)

A key resource for real-time space weather updates and forecasting.

Aditya-L1

An ISRO mission dedicated to observing the Sun and providing early warnings of space weather events.

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What’s next

ISRO's Aditya-L1 mission, launched in September 2023, is expected to provide continuous, real-time observations of solar activity, giving crucial early warnings of space weather events. Additionally, advancements in space weather modeling and data assimilation are enhancing predictive capabilities, allowing organizations like NOAA's Space Weather Prediction Center to provide more accurate and timely forecasts.

The takeaway

As our dependence on space-based technology continues to grow, understanding and preparing for the impacts of space weather will become increasingly vital. Improving our ability to predict and respond to solar flares and coronal mass ejections is crucial for ensuring the resilience of modern society and harnessing the potential of these space weather phenomena.