NOAA detects largest solar flare since 2017: What are they and what threats do they pose?

A powerful burst of energy on New Year's Eve created the largest solar flare that has been detected since 2017.

The event may sound serious, but the National Oceanic and Atmospheric Administration (NOAA) clarified that the general public had nothing to fear. However, the agency did put out a warning that the flare did pose the threat of temporarily disrupting high-frequency radio signals.

NOAA’s Space Weather Prediction Center also released an image of the flare Sunday, which appeared as a glowing spot on the sun's surface.

NASA’s Solar Dynamics Observatory similarly captured an image of the massive flare, which the space agency colorized in yellow and orange to emphasize the extreme intensity of the heat and ultraviolet light that the flare emitted.

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What are solar flares and what threats do they pose?

Considered our solar system's largest explosive events, solar flares occur when magnetic energy associated with sunspots is released, creating intense bursts of radiation.

Solar flares can last mere minutes, or can drag on for hours, depending on their intensity. NASA classifies solar flares based on their strength, with B-class being the smallest and X-class – which is what was detected Sunday – being the largest.

Weaker solar flares won't be noticeable here on Earth, but those with enough energy output to rank as an X-class have the potential to disrupt radio communications, electric power grids and navigation signals. In extreme cases, such powerful flares even pose risks to spacecraft and astronauts, according to NASA.

Each letter represents a ten-fold increase in energy output and includes a scale of 1 to 9 in each class. The exception is the X-class since there are flares that have been recorded exceeding 10 times the power of an X-1.

The most powerful of those occurred in 2003, when the sensors measuring it overloaded, accoding to NASA. The flare was later estimated to be about an X-45, which could have packed enough of a wallop to create long-lasting radiation storms that harm satellites and even give airline passengers flying near the poles small doses of radiation.

X-class flares also have the potential to create global transmission problems and world-wide blackouts, NASA says.

New Year's Eve solar flare is strongest in 6 years

Fortunately, Sunday's solar flare didn't come close to that 2003 output.

But the flare, rated as an X-5, was the strongest to be observed since Sept. 10, 2017 when an X8.2 flare occurred, according to NOAA.

The agency also tied the flare to the same region that produced an X-2.8 flare on Dec. 14 that caused radio blackouts in South America.

Solar flares and other solar activity, such as solar storms, are only expected to become more common by 2025 as the Sun reaches the height of its 11-year cycle, known as the solar maximum. The growing activity has brought with it fears of a potential "internet apocalypse" if a lengthy outage is triggered.

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at elagatta@gannett.com