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![](https://www.innovations-report.com/wp-content/uploads/post-pictures/solar-flare_572437.jpg)
An M-class solar flare erupts from the right side of the sun in this image from shortly before midnight EST on Jan. 12, 2015. The image blends two wavelengths of light -- 171 and 304 angstroms -- as captured by NASA's Solar Dynamics Observatory.
Credit: NASA/SDO
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 and communications signals travel.
To see how this event may affect Earth, please visit NOAA's Space Weather Prediction Center at http://spaceweather.
This flare is classified as an M5.6-class flare. M-class flares are a tenth the size of the most intense flares, the X-class flares.
The number provides more information about its strength. An M2 is twice as intense as an M1, an M3 is three times as intense, etc.