July 4 2011

The massive sunspot, which astronomers say is the size of Jupiter, is the strongest solar flare in four years, NASA said.

The Class X flash – the largest such category – erupted on Tuesday, according to the US space agency.

“X-class flares are the most powerful of all solar events that can trigger radio blackouts and long-lasting radiation storms,” disturbing telecommunications and electric grids, NASA said.

NASA’s Solar Dynamics Observatory saw a large coronal mass ejection (CME) associated with the flash that is blasting toward Earth at about 900 kilometres per second, it said.

The charged plasma particles are expected to reach the planet’s orbit on Thursday (US time).