THE NEXT STREAM OF SOLAR WIND: A minor stream of solar wind flowing from a southern hole in the sun's atmosphere is expected to reach Earth on Oct. 3rd or 4th. Its impact probably won't spark a full-fledged geomagnetic storm. Lesser geomagnetic unrest and auroras are possible, however, especially around the Arctic Circle. Aurora alerts: SMS Text.
A "STEVE STORM" HITS SCANDINAVIA: When a stream of solar wind hit Earth's magnetic field last Friday, Sept. 27th, forecasters expected an aurora storm around the Arctic Circle. Turns out, it was more of a "STEVE storm." Many sky watchers in Scandinavia saw the mauve ribbon of light for the very first time. Göran Strand photographed the event from Handöl, Sweden:
"I finally got to see STEVE," says Strand, who is a veteran observer of auroras, but had never seen STEVE before. "It all started when I noticed a faint green corona outside our mountain cabin. I grabbed my camera gear and headed out into the night. At my first stop along this road I encountered STEVE."
STEVE (Strong Thermal Emission Velocity Enhancement) looks like an aurora, but it is not. The phenomenon is caused by hot (3000°C) ribbons of gas flowing through Earth’s magnetosphere at speeds exceeding 6 km/s (13,000 mph). These ribbons appear during some geomagnetic storms, revealing themselves by their soft purple/mauve glow.
STEVE normally appears at latitudes around +50N to +55N, on rare occasions dipping down into the +40s. In this case, however, the sightings were at unusually high latitudes, topping +60N in Handöl, Sweden (+63.3N); Ruovesi, Finland (+62.0N); Turku, Finland (+60.5N) and, if we round up a little, Laguja, Estonia (+58.2N). This event shows that the habitat of STEVE may reach farther north than previously thought.
Realtime STEVE Photo Gallery
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A GREEN FLASH ON VENUS: You've heard of green flashes on the sun. But what about green flashes on Venus? They're real, and now is a good time to observe them. All you need is a body of water, a sunset, and a telescope.
"I saw one last week," reports eye-witness Paolo Palma of Rome, Italy. "At the end of the day on Sept. 26th I was watching the sunset from my deck overlooking the Tyrrhenian Sea. A fragment of the setting sun seemed to break away and turn a strong shade of green, like a leaf falling on the nearby sea."
It was a green flash--something that happens fairly often to the setting sun when temperature inversions and strong thermal gradients develop above the sea surface.
"The sky was clear," continues Palma, "and I had my Dobsonian telescope with me. I decided to swing my telescope up to Venus, which itself was only a few degrees above the horizon. As it sank toward the sea, it had a green flash, too!"
Green flashes on the sun happen because the low atmosphere acts like a prism, splitting the solar disk into primary R-G-B colors. Temperature gradients above the sea surface can magnify the green into an eye-catching flash. It's a type of mirage.
The same physics that makes green flashes on the sun can make green flashes on Venus. In fact, green flashes on Venus may be even easier to create.
Atmospheric optics expert Les Cowley explains: "Planets and especially point-source stars need less stringent conditions as evidenced by Paolo's observation of Venus spreading into a color strip while it was still well above the horizon. Mirages just do not get that high. Normal atmospheric refraction is sufficient to do this." When Venus approaches the horizon, mirage conditions kick in, magnifying the green for a truly verdant flash.
Now is a good time to observe Venusian green flashes. The second planet is just emerging from solar conjunction. So, when the sun sets into the waves, Venus is not far behind, sampling the same thermal conditions as the green-flashing sun. Seaside sky watchers should be alert for the phenomenon in the evenings ahead.
Observing tips: Venus may not be easy to find in the bright twilight of sunset. Having trouble? Try using binoculars when the sun is safely below the horizon. Please be very careful not to accidentally look at the sun through unfiltered optics of any kind. Even when the sun is hanging low, magnified sunlight can cause serious eye damage.
Realtime Green Flash Photo Gallery
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CROWD-FUNDING SPACE WEATHER RESEARCH: Did you know that cosmic rays in Earth's atmosphere are intensifying? It's true. We're monitoring the phenomenon with regular space weather balloon flights to the stratosphere. This student science program is not supported by any government grant or corporate sponsorship. Instead, we raise our research funds by selling these:
This pendant, and others like it, have touched the edge of space. We fly them to the stratosphere alongside our cosmic ray sensors for fundraising.
You can have one for $199.95. With a sterling silver backface that says "I Love You to the Moon and Back," these blue jewels make great anniversary, Christmas and birthday gifts. All sales support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education