Solar flare triggers radio blackout


Solar FlareThe sun fired off yet another intense solar flare 7/5, the latest in a series of storms from a busy sunspot being closely watched by space telescopes and astronomers. NASA’s Solar Dynamics Observatory snapped a daunting new image of a strong M-class solar flare that peaked 7/6 at 7:44 a.m. ET. The M6.1 flare triggered a moderate radio blackout that has since subsided, according to a Post story.

Radio blackouts can occur when the ionosphere is bombarded with X-rays or extreme ultraviolet light from solar eruptions. Disturbances in the ionosphere can change the paths of high and low frequency radio waves, which can affect robustness and data quality carried on these signals.

Radio blackouts are categorized on a scale from R1 (minor) to R5 (extreme). An R2 radio blackout can result in limited degradation of both high- and low-frequency radio communication and GPS signals, NASA officials said.

The eruption came from a sprawling sunspot, called Active Region 1515, which has been particularly dynamic this week. In fact, the sunspot region has now spewed 12 M-class solar flares since July 3, NASA officials said in a statement. The sunspot region is huge, stretching more than 62,137 miles long (100,000 kilometers) in length, they added.

This sunspot region has also produced several coronal mass ejections (CMEs), which are clouds of plasma and charged particles that are hurled into space during solar storms. Powerful CMEs have the potential to disrupt satellites in their path and, when aimed directly at Earth, can wreak havoc on power grids and communications infrastructure.

The CMEs that were triggered by this week’s solar flares, however, are thought to be moving relatively slowly, and will likely not hit Earth since the active region is located so far south on the face of the sun, NASA officials said. [More Solar Flare Photos from Sunspot AR1515]

But, the sunspot is slowly rotating toward Earth, and scientists are still monitoring its activity.

“Stay tuned for updates as Region 1515 continues its march across the solar disk,” officials at the Space Weather Prediction Center, a joint service of NOAA and the National Weather Service, wrote in an update.

X-class solar flares are the strongest sun storms, with M-class flares considered medium-strength, and C-class the weakest. Today’s M6.1 eruption is a little over half the size of the weakest X-class flare, NASA officials said.

The sun is currently in an active phase of its roughly 11-year solar weather cycle. The current cycle, known as Solar Cycle 24, is expected to peak in mid-2013.

See the story here


  1. Good talk. So, where did these blackouts occur? I backtracked this story to the Huffington Post and then to and from there to NOAA.

    see this link:

    Couldn’t find any specifics there either. Were these radio blackouts worldwide? Nationwide? Podunk? Were they long-term or short term? Did anyone notice? Anyone care? Did the sky fall? Maybe I just slept through it. Sigh.

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