Authorities warned of satellite service disruptions and GPS data errors as particles from the largest solar flares in 11 years began washing over Earth on the morning of Sept. 8, Japan time.
The particles have no impact on the human body, but past major flares have caused GPS trouble, damaged satellites and triggered blackouts, prompting the warning from the National Institute of Information and Communications Technology (NICT).
The Sept. 6 solar flares were the first in the X-class -- the most intense on the five-class scale -- seen since December 2006, with X-ray emissions from the second and much larger of the two at some 1,000 times normal output. NICT had initially projected the particles emitted by the flares would reach Earth between 3 p.m. and midnight on Sept. 8. However, the burst of energy was even larger than first thought, prompting NICT to push the projected arrival time up by about six hours.
While there have not yet been any reports of trouble, the flare's effects may emerge over the next two to three days, according to NICT. While smartphone and car GPS units automatically correct for positioning errors, the institute warned that "errors could be greater than usual."
Meanwhile, NASA has announced that two more large flares were observed at about 11:30 p.m. on Sept. 7, Japan time, the second also in the most intense X-class, though they emitted just one-seventh the X-rays of the Sept. 6 event.
Disruptions caused by past solar flares includes a major blackout in Canada in 1989 and damage to a Japanese X-ray observation satellite in 2000, while in 2006 a solar flare temporarily knocked out or hobbled GPS receivers.
Meanwhile, the aurora borealis can sometimes be seen in the skies of northern Hokkaido after an intense solar flare.
According to National Institute of Polar Research associate professor Ryuho Kataoka, there was also a smaller solar flare at about 5 a.m. on Sept. 5, Japan time. Kataoka added, "When there is a string of flares they increase in scale and speed, and there is now a possibility of an unexpectedly large magnetic storm. This isn't yet on a level that can harm Japan, but there is a risk of blackouts at extreme northern and southern latitudes."