THE LIGHT SHOW BEGINS: As predicted, Earth is entering a stream of high-speed solar wind on Jan 18th. This morning in Alaska, first contact with the stream produced a bright outburst of auroras. Sacha Layos sends this picture from the outskirts of Fairbanks:
"Temperatures dipped down to -45F, but that didn't stop us diehards from going out anyway," says Layos. "The auroras came out to play for the first time in over a week!"
The solar wind is flowing from a large hole in the sun's atmosphere. It's a broad stream that should influence our planet for the next two to three days. Arctic sky watchers can expect continued episodes of bright auroras in the nights ahead. Free: Aurora Alerts
VENUS IN A DROP OF WATER: Recipe for a great photo: Splatter a pane of glass with droplets of water. Place the glass in front of the sunset. Point a camera at the droplets and--click!
Photographer John Bell of Haversham, Bucks, UK followed the recipe and obtained the picture above on Jan. 17, 2017.
"I had been looking at macro photos of flowers through droplets and thought I'd try the same with the evening sky," explains Bell. "I taped a photoframe glass to a tree branch in my garden and framed the droplets using my Canon 5D MK2 with a sigma 106mm macro lens. The view was of Venus by a neighbour's tree."
Water droplets act as inverting lenses, so in the original photo the sunset was upside down. "Easily fixed," says Bell, who restored order by rotating the image 180 degrees. "Focusing was a bit difficult," he adds. "After all, water droplets are not perfect lenses." The result, however, was perfectly beautiful. More exposures are available here.
Realtime Space Weather Photo Gallery
FAR-OUT VALENTINE'S GIFT: For the past two years, Spaceweather.com and the students of Earth to Sky Calculus have been launching balloons to keep track of surging cosmic rays in the atmosphere. Our radiation monitoring program receives no support from corporate sponsors or government grants. Instead, we are crowd-funded. To that end, we offer for your consideration a truly far-out Valentine's gift:
On Dec. 18, 2016, the students of Earth to Sky Calculus flew 30 of these pendants to the stratosphere. You can have one for $69.95--including the rose, which has been pressed for safekeeping. Each order comes with a Valentine's card showing the pendant+rose in flight and telling the story of their trip to the stratosphere.
More out of this world gifts may be found in the Earth to Sky store. All proceeds support cosmic ray balloon flights and STEM education.
EARTH'S MAGNETIC FIELD RINGS LIKE A BELL: In the Lofoten Islands of Norway, Spaceweather.com reader Rob Stammes operates a magnetic observatory. Twenty-four hours a day, he measures the strength and direction of the local magnetic field as well as electrical currents running through the ground. During geomagnetic storms, his chart recordings go haywire. On Jan. 13th, something different happened. They rang like a bell:
"For about an hour, electrical currents in the ground beneath my observatory flowed back and forth with a sinusoidal period near 2 minutes," says Stammes. "This is rare."
These are natural ultra-low frequency oscillations known to researchers as "pulsations continuous" (Pc). The physics is familiar to anyone who has studied bells or resonant cavities. Earth's magnetic field carves out a cavity in the surrounding solar wind. Gusts of solar wind can make the cavity "ring" akin to a bell (references: #1, #2, #3). Human ears cannot hear this ringing; it is electromagnetic rather than acoustic. The physical effect is felt beneath our feet. As the cavity vibrates, magnetic fields swing back and forth, causing electrical currents to flow through the ground below.
The Pc waves Stammes detected are a variety known as Pc4, which oscillate in the frequency range 6.7–22 mHz. Such waves are good at energizing particles trapped in Earth's magnetic field and often cause local outbursts of bright auroras.
Realtime Airglow Photo Gallery