Powerful solar flares knock out radio signals across the US

NASA explained in a tweet that solar flares are powerful bursts of radiation that cannot harm humans on the ground but can disturb the atmosphere where GPS and communications signals travel.

Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth’s atmosphere to physically affect humans on the ground. However – when intense enough – they can disturb the atmosphere in the layer where GPS & communications signals travel.

— NASA Sun & Space (@NASASun) August 7, 2023

As per NASA, the previous solar flare happened on Friday, August 5, and peaked at 6:21 pm Eastern Time. This solar flare was also an X-class occurrence but slightly more substantial than Monday’s flare, with an intensity of X1.6.

Impact on ground

Solar flares and CMEs do not directly threaten humans on the ground, as Earth’s atmosphere protects us from harmful radiation. However, they can penetrate the atmosphere in the layer where GPS and communications signals travel, resulting in interference or loss of signals. They can also damage satellites and spacecraft exposed to the solar storm.

For instance, last September, ESA and NASA’s Solar Orbiter spacecraft encountered a CME that was ejected from the Sun a few days earlier. The spacecraft was designed to withstand the harsh environment of the heliosphere, the region of space dominated by the Sun’s influence. However, other satellite missions may not be so lucky if caught off guard by a solar flare or a CME.

Solar activity follows an 11-year cycle, with high and low activity periods. The current cycle, known as Solar Cycle 25, began in December 2019 and is expected to peak in July 2025. Scientists use various instruments and satellites to monitor the Sun’s activity, such as NASA’s Solar Dynamics Observatory and NOAA’s Geostationary Operational Environmental Satellite system. By studying the Sun’s behavior, they hope to understand its impact on Earth and space better.