GEOMAGNETIC STORM WATCH: NOAA has issued a minor geomagnetic (G1-class) storm watch for today, March 9th, when a CME is expected to graze Earth's magnetic field. Normally, the glancing blow would not cause a magnetic storm. However, at this time of year, even a weak impact can do the job because of the equinox Russell-McPherron effect. Aurora alerts: SMS Text
THESE RED LIGHTS ARE NOT AURORAS: Last Sunday, March 3rd, a CME hit Earth's magnetic field. The surprisingly strong impact sparked a G2-class geomagnetic storm with bright auroras around the Arctic Circle. Upon closer inspection, however, not all of those lights were auroras. Some were "SAR arcs":
During the storm, Märt Varatu photographed this red 'bow over Kiia küla, Estonia. "It was a strong SAR arc," he says.
SARs were discovered in 1956 at the beginning of the Space Age. Researchers didn’t know what they were and unwittingly gave them a misleading name: "Stable Auroral Red arcs" or SARs. In fact, they are not auroras.
Auroras appear when charged particles rain down from space, hitting the atmosphere and causing it to glow like the picture tube of an old color TV. SARs form differently. They are a sign of heat energy leaking into the upper atmosphere from Earth’s ring current system, a donut-shaped circuit carrying millions of amps around our planet. During the geomagnetic storm of March 3rd, this ring current sprang a significant leak.
The same red arcs were widely observed from Latvia to eastern Russia. Vladimir Nerush photographed this fragment just east of Moscow:
"It emerged from the trees and passed right by the Pleiades," says Nerush. "The red color was so pure."
Indeed, SAR arcs are among the reddest things in the sky, with a monochromatic glow at 6300 Å that comes from atomic oxygen in the upper atmosphere. The human eye is relatively insensitive to light at this wavelength; we have a hard time seeing SAR arcs. Cameras catch them easily, though. Pro tip for photographers: Use a 6300 Å filter.
more images: from Juris Seņņikovs of Dobele, Latvia; from Ilgonis Vilks of Jurmala, Latvia
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18K GOLD "LOVE YOU TO THE MOON" LOCKET: This is a very special locket. It's heart-shaped, plated with 18K gold, and we will fly it again during this year's total eclipse of the sun. Keep reading...
On Jan. 26, 2024, the students of Earth to Sky Calculus launched this locket to the stratosphere onboard a cosmic ray research balloon. At the apex of the flight, it floated 111,535 feet above the Sierra Nevada mountains of central California:
Buy it now for $149.95, and we'll fly it again--FOR FREE--during the total solar eclipse on April 8, 2024. The students will be launching multiple balloons from the path of totality in Texas. Your pendant will go along for the ride, touching the shadow of the Moon at the edge of space. (Simply type "FLY IT AGAIN" in the comments box at checkout.)
The locket, which opens to hold a personal photo or other small item, comes with a greeting card showing the jewelry in flight and telling the story of its journey to the edge of space.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
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