A long-duration, M3-class solar flare erupted on the Sun Thursday morning, sending a plasma wave of charged particles — known as a Coronal Mass Ejection (CME) — toward Earth at an estimated speed of 630 miles per second.
The CME is expected to reach earth on Saturday morning. Early predictions suggested the possibility of strong geomagnetic disturbances, with intensified aurora (also known as Northern Lights) visible as far south as the central U.S.
While M-class CME’s can cause communications blackouts, indications from NASA are that this one should cause no adverse effects.
Solar flares are classified by the strength of their x-ray emissions as measured near Earth by the GEOS spacecraft. Classes include A, B, C, M and X, with each class 10 times more powerful than its predecessor. Within this logarithmic scale of classes is a linear scale ranging from 1-9, such that an M3 flare is three times as powerful as an M1.
The strength of a solar flare is not the only factor in predicting its effect on Earth’s magnetosphere, however, as size, direction and speed also play roles. This particular M3 is described as a halo CME, indicating that it is wide and directed toward Earth.
The video above, from NASA’s Solar Dynamics Observatory, shows a close-up of sunspot 1401 region as the flare erupts in a combination of light wavelengths. Across the top is a graph of corresponding X-ray measurements taken by the GOES 15 satellite.
