Sun remains active with fourth strong solar flare of 2013

GREENBELT, Md., May 15 (UPI) -- NASA says activity on the sun is ongoing as the fourth X-class solar flare of this year erupted late Tuesday, causing temporary radio blackouts on Earth.

The latest flare, which peaked at 9:48 p.m. EDT Tuesday, was rated as an X1.2 flare, on a numerical scale in which each number is 10 times as intense, so for example an X2 is 10 times as powerful as in X1, the space agency said Wednesday.

The flare was also associated with a non-Earth-directed coronal mass ejection, NASA said. Flares and CMEs are related phenomena; solar flares are powerful bursts that send light and radiation into space, while CMEs blast billions of tons of solar material out from the sun's surface.

The CME associated with this latest flare left the sun at around 745 miles per second, beginning at 10:18 p.m. EDT Tuesday, scientists said.

It isn't Earth-directed, NASA said but may pass the orbits of several space missions including the Spitzer space telescope and mission operators have been notified.