The Sun unleashed a torrent of X-rays on Wednesday, blacking-out high-frequency radio communications in North and South America, including states around the Gulf of Mexico still recovering from Hurricane Katrina. And forecasters say more major solar flares may be on the way.
The solar flare was the fourth largest in 15 years, in terms of X-ray emissions, and the fifth largest since 1976.
It spewed from a sunspot cluster six times the diameter of Earth. Because the active area was just rotating over the Sun鈥檚 horizon, the flare was not pointed directly at Earth (see it , in animated gif format). But the planet still felt its effects.
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鈥淲e did get a minor solar radiation storm out of this, which is very unusual given the sunspot鈥檚 position,鈥� says Larry Combs, a space weather forecaster for US National Oceanic and Atmospheric Administration Space Environment Center (SEC) in Boulder, Colorado.
The flare 鈥� which erupted at 1340 EDT (1840 GMT) 鈥� caused a complete blackout for those using high-frequency radio communications on the day-lit side of Earth. Air traffic controllers experienced moderate communications problems on Wednesday, Combs says.
Extreme situation
The area that produced the flare, now known as sunspot region 808, was also responsible for producing brilliant auroras in August. The sunspot has since made one revolution around the Sun. If the region remains active, firing more particles our way, September could be a good month for aurora-watching as well.
The sunspot could rotate to the centre of the face of the Sun, as seen from Earth, by next week. If it released a solar flare then, Earth would be in its direct path. 鈥淚f that particular storm had been right at the centre of the Sun, there鈥檚 no doubt that it could have been extreme situation for radio blackouts,鈥� Combs told New 杏吧原创.
This region has 鈥済reat flare potential鈥� according to SEC reports, and could produce moderate-to-strong radio blackouts on Earth in the coming days as the sunspot cluster traverses the Earth-facing side of the Sun.
The number of sunspots varies on an 11-year cycle. It is currently near the trough of the cycle, but that does not preclude the formation of strong flares, as this week has shown.
