The sun let off its most powerful flare of 2013 Thursday, according to NASA.
The M-class flare is less strong than some of the flares given off by the sun in 2012, but Thursday's explosion was associated with an Earth-directed coronal mass ejection—a phenomenon that emits billions of charged particles into space. Those particles can temporarily interfere with satellites, including the ones that are responsible for GPS systems and airplane navigation.
Solar radiation is absorbed by the time it hits the Earth's atmosphere, so solar storms cannot have any physical effects on humans. But particularly strong solar storms can knock power grids offline, and a solar storm in 1859, called the Carrington Event, knocked telegraph lines out of commission for several days. In 1989, a solar storm knocked Quebec's power out for nine hours.
Though the beginning of 2013 has been relatively quiet for solar storms, there were several so-called "X-class" flares during 2012, one of which temporarily knocked military satellites offline. Thursday's flare was the weakest flare that is still able to cause adverse effects to satellites.
NASA says the sun reaches a state called "solar maximum" every 11 years where it is more likely to give off strong, frequent storms — it'll hit that peak toward the end of this year.
"It is normal for there to be many flares a day during the sun's peak activity," NASA says.
SOHO also captured this coronagraphic (a telescopic attachment designed to block out the direct light from a star so that nearby objects can be seen) image of the coronal mass ejection as it moves further out into the heliosphere. (Credit: ESA&NASA/SOHO/GSFC)
NASA's Solar Dynamics Observatory captured this image of an M6.5 class flare at 3:16 a.m. EDT Thursday. This image shows a combination of light in wavelengths of 131 and 171 Angstroms. (Credit: NASA/SDO)