It’s #SunDay! Here’s your space weather report for Oct. 9-15: •3 M-class flares •0 C-class flares •19 coronal mass ejections •1 geomagnetic storm This video from NASA’s Solar Dynamics Observatory shows the week’s activity. After the Oct. 10 geomagnetic storm, which led to aurora sightings across northern Europe, Canada, and the northeastern United States, it was a relatively calm week on the Sun. The Moon makes a special guest appearance in this week’s video beginning at about 0:36. Note the sharp outline of the Moon’s edge. That’s because the Moon has almost no atmosphere to scatter sunlight. At about 2:30, we also see a calibration maneuver, which the spacecraft performs periodically to account for changes in its instruments’ optics over time. More about solar activity: go.nasa.gov/4bLKwte

It’s #SunDay! Here’s your space weather report for the week of Sept. 18 - Sept. 24: • 0 M-class flares • 1 C-class flare • 14 coronal mass ejections • 0 geomagnetic storms This video from NASA’s Solar Dynamics Observatory shows the week’s activity, though a momentary data gap (which has since been resolved) left out imagery from Sept. 24. It was another quiet week on the Sun. The coronal holes that took form last week — the dark “stripes” that indicate cooler, darker regions where fast solar wind escapes to space — have continued sending high-speed streams toward Earth, though none powerful enough to create a geomagnetic storm. September 22 marked the beginning of autumn in Earth's Northern Hemisphere, as well as a high point in “aurora season.” Aurora season happens twice a year around the equinoxes, when Earth’s roughly 23-degree “tilt” tips our planet’s magnetic field so it more easily lines up with the Sun’s magnetic field. As a result, in September and October and in March and April (around the equinoxes), geomagnetic storms and auroras tend to become more common and more intense. The phenomenon is known as the Russell-McPherron effect. More about solar activity: go.nasa.gov/4bLKwte