AN UPTICK IN SOLAR FLARE ACTIVITY: Two new sunspots are rapidly emerging on the solar disk, and one of them (AR2615) is crackling with C- and M-class solar flares. So far the eruptions are minor. However, they do represent a noteable uptick in activity compared to the absolute quiet of recent months. Free: Solar flare alerts.
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 more 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. Stay tuned.
NOCTILUCENT CLOUDS APPEAR OVER ANTARCTICA: This just in from NASA's AIM spacecraft: The sky above Antarctica is glowing electric blue. A ring of bright noctilucent clouds (NLCs) has formed around the South Pole, shown here in a Nov. 24th image taken by the spacecraft's Cloud Imaging and Particle Size (CIPS) Instrument:
"This season started on Nov. 17th, and is tied with 2013 for the earliest southern hemisphere season in the CIPS data record," says Cora Randall, a member of the AIM science team at the University of Colorado.
NLCs are Earth's highest clouds. They form more than 80 km above Earth's surface. Indeed, they are a mixture of Earth and space: Wisps of summertime water vapor rising from the planet below wrap themselves around meteoroids, forming tiny crystals of ice. Emphasis on summertime; NLCs appear on the eve of summer in both hemispheres.
There is growing evidence that noctilucent clouds are boosted by climate change. In recent years they have been sighted at lower latitudes than ever before, and they often get started in earlier months as well.
"The early start of the 2016 season was not at all a surprise," says Randall. "The southern hemisphere polar stratospheric winds switched to their summer-like state quite early this year."
Readers, you can monitor developments over Antarctica right here on Spaceweather.com. "Daily daisies" from NASA's AIM spacecraft are automatically posted every 24 hours, showing the dance of electric-blue around the frozen continent.
Realtime Noctilucent Cloud Photo Gallery
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.
Realtime Space Weather Photo Gallery