ANCHORAGE (KTUU) - The sun released another huge burst of energy in the form of a solar flare on Sunday. This is the latest in a series of solar flares from a specific active region of the sun. The flare on Sunday has been classified as an X8.2. The “X” indicates it is in the most intense class of flares and the number shows the strength, for example an X2 is twice as strong as an X1, an X3 is three times as strong, etc.
While solar flares emit intense bursts of x-rays and extreme ultraviolet rays, what creates the aurora are Coronal Mass Ejections, or CMEs. Chris Fallen, Research Assistant Professor with the Geophysical Institute at the University of Alaska Fairbanks, describes a CME like this, “it’s like a big ball of plasma, hot solar wind and plasma emanating from the sun and it travels at a very high rate of speed.”
Fallen says solar flares and CMEs are really two separate events which typically, but not always, occur together.
The fast moving particles released from the sun during CMEs slam into Earth’s atmosphere and cause the aurora. It takes two to four days for the particles from the sun to hit Earth’s atmosphere which means if we’re going to see the aurora from this latest eruption it will most likely occur Tuesday night, September 12.
Due to the sun’s rotation, the active sunspot is now on the side of the sun’s disc, not facing Earth directly. Earth is unlikely to get a direct hit so the aurora might not be as powerful.
According to Fallen, “the Coronal Mass Ejection was more off to the side of the Earth but the way the sun’s magnetic field is structured right now there is still a chance that this Coronal Mass Ejection could at least graze the Earth, but at this moment, it’s a little too early to say quite where that mass of plasma is going to go.”
Solar flares are powerful bursts of radiation but NASA says, “harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground.” If the radiation is strong enough, it can interrupt communication signals including HF radios and GPS.
Last Thursday, this same region emitted two major solar flares. The first was a X2.2. The second an X9.3. This series of flares from this active region began on August 29, 2017.