Yahoo News Giant Sunspot Sparks Massive Solar Flares
Some of the most significant solar flare activity in nearly 25 years is producing spectacular pictures and could impact on communication signals on Earth, experts warn.
The activity triggered from a massive sunspot in a region of the sun known as AR2192 began on 19 October and can be seen with the naked eye if the conditions are right.
Since then six "substantial" flares have been recorded and the level of solar activity is likely to be high for the next few days as the sunspot grows.
NASA's Solar Dynamics Observatory (SDO), which watches the sun constantly, captured images of the event.
It reported: "Solar flares are powerful bursts of radiation.
"Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however - when intense enough - they can disturb the atmosphere in the layer where GPS and communications signals travel."
The latest flare is classified as X3.1-class.
X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, and X3 is three times as intense.
The flare erupted from an extensive active region on the sun that, at almost 80,000 miles across, is the largest in 24 years.
The US National Oceanic and Atmospheric Administration (NOAA) said communications impacts were "likely in the Atlantic Ocean region".
SpaceWeather.com said: "Big sunspots tend to produce strong flares, and AR2192 is no exception.
"It is crackling with magnetic activity. In the past three days alone it has unleashed 3 X-class flares and 8 M-flares. The most intense of these flares have caused HF radio blackouts and other communication disturbances on the dayside of Earth."
It added that the activity is seen best with the naked eye when the sun is dimmed by low cloud or fog.
According to NASA a solar flare is "an intense burst of radiation coming from the release of magnetic energy associated with sunspots. Flares are our solar system’s largest explosive events".
