As we move into the peak of solar cycle 25, activity on the Sun has been ratcheting up.
As we move into the peak of solar cycle 25, activity on the Sun has been ratcheting up. One sign of that appeared in Earth’s atmosphere in the form of an impressive display of the aurora borealis, or northern lights, which was visible to observers on the ground beyond the Arctic Circle and deep into the midlatitudes in October 2024.
Millions of skywatchers were treated to the green, pink, and red lights of the aurora overnight on October 10-11. At 1:55 a.m. Eastern Time (05:55 Universal Time) on October 11, the VIIRS (Visible Infrared Imaging Radiometer Suite) on the NOAA-20 satellite acquired this image of the aurora. The VIIRS day-night band detects nighttime light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as city lights, reflected moonlight, and auroras.
In this view, the northern lights appear as ribbons of white crossing parts of Minnesota, Wisconsin, and Michigan in the U.S., and several provinces in Canada. But auroras are dynamic, and different coverage and patterns of light would have been visible at other times of the night. While these satellite data are shown in grayscale, viewers on the ground saw colors from green (the most common) to purple to red. Atmospheric compounds found at different altitudes influence an aurora’s color.
Read more at NASA Earth Observatory
Photo Credit: Waschdel via Pixabay
