Scientists are warning that a blast of charged particles from the sun may disrupt GPS and wireless communications from Friday afternoon to midnight, Japan Time.
Large eruptions called solar flares occur in dark spots of the sun. A large-scale solar flare occurred shortly before 9:00 PM, Japan Time, on Wednesday.
Researchers at the National Institute of Information and Communications Technology say a similar sized flare was last observed 11 years ago, in 2006.
They say charged particles released by the latest eruption are likely to reach the Earth between around 3:00 PM and 12:00 AM Friday.
The institute warns that the particles will disrupt the Earth's magnetic field. It says this could cause GPS devices to show errors up to several tens of meters. Some wireless communications could also be affected.
The latest solar flare will reportedly have no impact on human health.
Solar flares have affected the Earth in the past. A flare in 1989 caused massive blackouts in Canada, and one in 2003 damaged a Japanese satellite.
Experts say solar flares can also generate auroras far from the north and south poles, in places where the phenomenon is not usually observed.