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: