The first of two coronal mass ejections have slammed into Earth's magnetic field and space weather forecasters predict this rare one-two punch could result in ‘supercharged' auroral displays.
Incoming! Sun Launches Two CMEs at Earth
On Monday (Sept. 8), the sun generated an M-class (moderate) flare from active region (AR) 2158, which was facing Earth at the time. Solar observatories started tracking a magnetic bubble of energetic solar plasma - known as a coronal mass ejection (CME) - heading our way. On Wednesday (Sept. 10), the same active region generated a second, more powerful X-class flare that also generated an Earth-directed coronal mass ejection.
Today, the first of the two CME's has hit, triggering a geomagnetic storm - albeit a minor one. However, space weather forecasters and sky watchers alike are excited by the prospect for the second CME that is predicted to slam into the Earth's magnetosphere by late Friday.
"A G3 (Strong) Geomagnetic Storm Watch is still in effect for September 13th due to the combined influence of this CME and the one projected to arrive late on the 12th," writes an NOAA Space Weather Prediction Center bulletin.
NEWS: Sun Erupts With Powerful Earth-Aimed Solar Flare
Currently, a "G1″ geomagnetic storm is underway, which is classed as a minor storm, but it may reach a moderate (or "G2″) strength over the coming hours. When the second CME begins interacting with the magnetosphere tonight, a major (or "G3″) storm may commence, bringing potentially spectacular auroral displays to higher latitudes.
The NOAA have also warned that the interplanetary environment surrounding Earth will see an increase in solar radiation. We are currently experiencing an "S1″ (minor) solar radiation storm which signifies the presence of highly energetic particles that have arrived with the first CME. When the second CME hits, the solar radiation storm may be upgraded to a moderate, or "S2″, level.
The prediction of the severity of geomagnetic storms and solar radiation storms is critical for satellite operators and power grid managers, for example. As local space is buzzing with high-energy particles from the sun (mainly electrons and protons), communications satellites can be at risk. Forewarning of solar radiation storms help operators to keep their satellites safe.
Epic Aurora Photos From the Space Station
Likewise, as geomagnetic storms get under way, an increased quantity of highly charged particles not only create wonderful auroral displays, they can also induce powerful electrical currents through the atmosphere, potentially overloading national power grids. Preventative measures are put in place by reducing the current flowing through power grids, making them less susceptible to costly (and potentially dangerous) overload scenarios.
"We don't expect any unmanageable impacts to national infrastructure from these solar events at this time, but we are watching these events closely," said SWPC Director Thomas Berger on Thursday during a press conference.
Earth often gets hit by CMEs, but what is rare about these events is that we have two Earth-directed CME's hitting our planet within hours of one another. This may "supercharge" the effects of the first geomagnetic storm that is currently vibrating through the Earth's global magnetic field.
NEWS: Solar Boom: Sun Blasts X-Class Flare Right At Us
Though exciting, the likelihood of geomagnetic storms can be hard to predict. Although we know a CME is headed our way, its magnetic orientation needs to be just right to fully interact with the Earth's magnetosphere. Should these magnetic conditions be met, however - and the CME's magnetic field is "geoeffective" - both the CME's magnetic field and the Earth's magnetic field will interact in such a way that the solar plasma the CME contains can be dumped deep inside the magnetosphere's "shell", dictating how extensive and intense the resulting aroral displays will be.
During the most intense geomagnetic storms, aurorae can be seen at surprisingly low latitudes. But sometimes, even the biggest CMEs can pass the Earth with very little impact. In short, space weather prediction is a very tough science, but with our increased understanding of the solar environment and the sophisticated solar observatories we put into space, we are able to at least forecast when a CME will hit and prepare accordingly.
So keep your eye on the skies tonight and through the weekend for the possibility of seeing Nature's most impressive light display, particularly if you are located in high latitude regions of the planet.