Watch: Powerful solar flare knocks out shortwave radio across Pacific

More powerful flares are expected today.
Ameya Paleja
An illustration of a solar flare
An illustration of a solar flare


A medium-intensity solar flare briefly knocked out shortwave radio communication over the Pacific Ocean in the evening hours of February 7. The flare originated from the sunspot AR3213, which is currently facing the Earth.

Sunspots are areas of high magnetic field intensity capable of temporarily halting the convection process on the Sun's surface. This causes the temperature in the area to drop significantly, making it appear darker when observed from the Earth, hence the name sunspots.

Scientists have been observing sunspots over centuries and have determined that their number increases as the Sun approaches the peak of its solar cycle. The cycle that takes 11 years to complete sees the solar poles flip at their peak, accompanied by many solar flares and coronal mass ejections.

Solar flares

Solar flares are eruptions of electromagnetic radiation caused when the energy stored in intense magnetic fields is suddenly released. This causes material on the solar surface to heat to millions of degrees in a concise period, releasing radiation from radio rays to gamma rays.

The intensity of these flares is classified on their strength, where classes A, B, and C are low-intensity flares, with Class X being the highest intensity flares. M-class flares are moderate-intensity flares.

The Earth's atmosphere absorbs most of the radiation coming from solar flares. However, the intense energy from medium to high-intensity solar flares can disrupt molecules in the upper layers of the atmosphere, which are used for radio communication and navigational purposes.

Sunspot AR3213

AR3213 is a massive sunspot that stretches 62,000 miles (100,000 km) on the solar surface, large enough to fit eight Earth-sized planets. On February 7, it let out an M-class solar flare, which NASA's Solar Dynamics Observatory captured.

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According to, this event caused a blackout over shortwave radio at about 6:07 pm EST (2307 GMT).

While this was short-lived, more sunspots are now facing the Earth. According to predictions from the National Oceanic and Atmospheric Administration (NOAA), chances of further M-class flares have now increased to 55 percent.

Sunspot AR3213 is also facing the Earth, and there is a 15 percent likelihood that it might give out a higher intensity flare, belonging to the X-Class. If it does, there is a likelihood of a significant radio blackout that could affect many people in other parts of the globe.

Solar scientists are still figuring out ways to predict the time of eruption for a solar flare accurately.

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