JACKSONVILLE, Fla. - On Sunday night into Monday morning, the Solar Dynamics Observatory Satellite of NASA showed a solar flare on the sun released a coronal mass ejection towards Earth that could impact us on Thursday.
The solar flare was not particularly large, but NOAA has issued A G1 (Minor) geomagnetic storm watch, in effect for Thursday. The G1 Watch has been issued due to the likely response associated with the arrival of an asymmetric halo coronal mass ejection glancing blow late on the Wednesday to early Thursday. The CME was first observed in at 8:25 p.m. on Sunday.
Current background solar wind speeds are slower than routine model predictions, so the forecast arrival timing of the CME has been slowed from the WSA-Enlil CME model run prediction.
Potential impacts on Earth
- A more visible aurora (Northern Lights) in northernmost to mid latitudes with clear skies
- Satellite communication may be effected on a minor scale
- Weak power grid fluctuations are possible but not likely
- As a precaution, the SWPC Forecast Office has switched from their primary operational spacecraft, DSCOVR, to our backup, ACE, through the duration of an anticipated CME event.
Should you be worried?
Nope- these happen pretty often. NASA estimates there are around 150 solar storms per year, although most do not effect Earth, instead the explode out from the sun into empty space.
What does all of this mean?
According to NASA, solar activity associated with Space Weather can be divided into four main components: solar flares, coronal mass ejections, high-speed solar wind, and solar energetic particles.
- Solar flares impact Earth only when they occur on the side of the sun facing Earth. Because flares are made of photons, they travel out directly from the flare site, so if we can see the flare, we can be impacted by it.
- Coronal mass ejections, also called CMEs, are large clouds of plasma and magnetic field that erupt from the sun. These clouds can erupt in any direction, and then continue on in that direction, plowing right through the solar wind. Only when the cloud is aimed at Earth will the CME hit Earth and therefore cause impacts.
- High-speed solar wind streams come from areas on the sun known as coronal holes. These holes can form anywhere on the sun and usually, only when they are closer to the solar equator, do the winds they produce impact Earth.
- Solar energetic particles are high-energy charged particles, primarily thought to be released by shocks formed at the front of coronal mass ejections and solar flares. When a CME cloud plows through the solar wind, high velocity solar energetic particles can be produced and because they are charged, they must follow the magnetic field lines that pervade the space between the Sun and the Earth. Therefore, only the charged particles that follow magnetic field lines that intersect the Earth will result in impacts.
Coronal Mass Ejection
According to NOAA, a coronal mass ejection is a huge explosion of magnetic field and plasma from the Sun's corona. When CMEs impact the Earth’s magnetosphere, they are responsible for geomagnetic storms and enhanced aurora. CMEs originate from highly twisted magnetic field structures, or “flux ropes”, on the Sun, often visualized by their associated “filaments” or “prominences”, which are relatively cool plasmas trapped in the flux ropes in the corona. When these flux ropes erupt from active regions on the Sun (regions associated with sunspots and very strong magnetic fields), they are often accompanied by large solar flares; eruptions from quiet regions of the Sun, such as the “polar crown” filament eruptions, sometimes do not have accompanying flares.
CMEs travel outward from the Sun typically at speeds of about 300 kilometers per second. The fastest CMEs erupt from large sunspot active regions, powered by the strongest magnetic field concentrations on the Sun. These fast CMEs can reach Earth in as little as 14-17 hours. Slower CMEs, typically the quiet region filament eruptions, take several days to traverse the distance from the sun to Earth. Because CMEs have an embedded magnetic field that is stronger than the background field of the solar wind, they will expand in size as they propagate outward from the Sun. By the time they reach the Earth, they can be so large they will fill half the volume of space between the Sun and the Earth. Because of their immense size, slower CMEs can take as long as 24 to 36 hours to pass over the Earth, once the leading edge has arrived.
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