UNEXPECTED SOLAR FLARE: Yesterday, Nov. 29th at 1723 UT, new sunspot AR2615 surprised forecasters when it suddenly erupted, producing an impulsive M1-class solar flare. NASA's Solar Dynamics Observatory caught the flash of extreme ultraviolet (UV) radiation:
Following months of negligible solar flare activity, the sudden emergence of AR2615 and its subsequent explosion caught forecasters off guard. A pulse of UV and X-radiation from the explosion ionized the upper layers of Earth's atmosphere over the Pacific Ocean: map. This affected the normal propagation of radio waves. Mariners and ham radio operators may have noticed brief fade-outs and/or unexpected hops at frequencies below ~10 MHz.
A few hours later, it happened again. At 23:38 UT on Nov. 29th, AR2615 produced an M1.2-class flare, causing a short-lived radio blackout over Australia.
This is *not* a major space weather event, but it is a break from the sun's recent deepening quiet. NOAA forecasters estimate a 10% chance of additional M-flares on Nov. 30th. Free: Solar flare alerts.
Realtime Space Weather Photo Gallery
MESOSPHERIC BORE (IT'S NOT WHAT YOU THINK): This month, a lot is happening in the mesosphere. The mesosphere is a layer of Earth's atmosphere above the stratosphere; it is the realm of sprites, noctilucent clouds (NLCs), and airglow. Starting on Nov. 17th, NASA's AIM spacecraft spotted bright noctilucent clouds forming in the mesosphere above Antarctica. Then, in an apparently unrelated development on Nov. 24th, the normal dome of airglow over China split in two. Xiao Shuai photographed the event from Mount Balang in Sichuan:
This is called a "mesospheric bore"--and not because it's dull. A bore is a type of atmospheric wave with deep ripples at its leading edge. Indeed, you can see the ripples in Shuai's photo separating the zone of airglow from clear sky.
Bores fall into the category of "gravity waves"—so called because gravity acts as the restoring force essential to wave motion. Analogy: Boats in water. When a boat goes tearing across a lake, water in front of the boat is pushed upward. Gravity pulls the water back down again and this sets up a wave.
In this case, instead of water, rarefied air is the medium through which the wave propagates. The sudden boundary in the airglow layer is probably akin to a hydraulic jump. But what created the disturbance in the first place? (What is the 'boat'?) No one knows.
"There may be updates in the coming days as scientists from NASA and the Chinese Academy of Science check data from satellites to learn more about this event," says Jeff Dai, who has been helping Xiao Shuai process and communicate his extraordinary images. "Also, we encourage other photographers from Thailand, Myanmar, Bangladesh and India to submit their images of the wave."
BUY A TICKET TO THE EDGE OF SPACE: Christmas shopping for a young scientist? Consider this: For the holiday season only, we're reducing the cost of payload space on Earth to Sky Calculus balloons from $500 to only $299.95. Buy an edge of space gift certificate before Dec. 25th and your student can send an experiment, photo, or keepsake item to the stratosphere, completely supported by an Earth to Sky Calculus launch and recovery team.
This is not only a great Christmas gift, but also a good kickstarter for science fair projects. Experiments will be flown and returned along with video footage, GPS tracking, temperature, pressure, altimetry and radiation data.
To take advantage of the discounted rate, payment must be received before Dec. 25th. However, the flight can take place at any time in the next 12 months.
Conditions: No mammals. Plants and non-pathogenic microbes are allowed. Generally speaking, experiments should weigh less than ~300 grams and occupy a volume less than ~64 cubic inches. A Skype brainstorming session is included with each certificate. Dr. Tony Phillips and other members of the Earth to Sky team will chat with students to help them craft an experiment that will work in the harsh environment of the stratosphere.
More edge of space Christmas gifts may be found in the Earth to Sky Store.