SpaceWeather.com Archive — Wed, Aug 21, 2024

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LUNAR OCCULTATION OF SATURN: This morning along a path of totality stretching from South America to Europe, sky watchers saw the full Moon swallow Saturn. The lunar occultation lasted more than 45 minutes and produced some very rare photos of ringed Saturn near the cratered edge of the Moon. Browse the gallery!

An HDR animation of the occultation from Raffaello Lena in Rome, Italy

Realtime Saturn Photo Gallery
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AURORAS SHOULD NOT BE ORANGE (BUT THEY ARE): During last week's severe (G4-class) geomagnetic storm, Tony Bendele of Pennsylvania saw something rare and a little mysterious. "Orange auroras!" he says. "Yes, Orange. I had never seen this color in auroras before." Note the boxed hue in Bendele's Aug 12th photo:

"At first, I thought something was wrong, so I checked this image numerous times. The color orange is really there," he says.

What's so mysterious? There's no element in Earth's atmosphere capable of making bright orange. It's simple chemistry. Every aurora color has a matching atom or molecule. For instance, oxygen atoms produce red and green. Nitrogen molecules give us purple and, sometimes, pink. Theoretically, N2, N2+, and O2+ can produce emissions at orange wavelengths. However, these emissions are very weak compared to other colors produced by the same molecules. Auroras should not be orange.

Yet look at this picture taken during the same storm by Friedrich Deters just North of Minneapolis, Minnesota:

Orange was all over the sky--a phenomenon observed not only by Deters in Minnesota and Bendele by Pennsylvania, but also by many others across North America and Europe.

Aurora physicist Kjellmar Oksavik of the University of Bergen in Norway has given the phenomenon a lot of thought, and he believes he has the answer: "It's not a mystery molecule. It's a mixing of different colors."

During typical geomagnetic storms, red auroras and green auroras are well separated; red on top, green on the bottom. However, when geomagnetic storms become intense, as happened on Aug. 12th, red and green can overlap in a zone 150 km to 200 km high. "The mixture fools the camera and the eye to believe that it is orange. In reality, it is both red and green at the same time," he says.

Mystery solved? Probably. It should be easy to check as Solar Cycle 25 intensifies. Photographers, be alert for orange, and submit your pictures here.

more orange: from Caroline Haldeman near Flagstaff, AZ; from Joel Ryan of Southland, New Zealand; from Noeleen Lowndes near Skagway, AK; from Cynthia Farr-Weinfeld of Sebago Lake in Raymond, Maine; from Ed Kreminski of Westerville, Ohio

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STORM TROOPER WHISKEY DECANTER: It's the perfect gift for a Star Wars fan--the Storm Trooper Whiskey Decanter. The 750 ml decanter hitched a ride onboard a cosmic ray balloon floating 106,066 feet above the Sierra Nevada mountains of central California:

You can have it for $124.95. The decanter comes with a greeting card showing the item in flight, and telling the story of its journey to the stratosphere and back again. All purchases from the Earth to Sky Store help pay the helium bill for our student ballooning program.