STRUGGLING SUNSPOT: A new sunspot (AR2690) emerged on Dec. 6th, breaking a string of 5 spotless days. Today, Dec. 7th, it is already fading away: 24-hr movie. Sunspots tend to struggle during the declining phase of the solar cycle, and this one is no exception. It will likely be gone tomorrow. Free: Aurora Alerts.
WHEN WILL THE NEXT STREAM OF SOLAR WIND ARRIVE? On Dec. 6th, as Earth was exiting a fast-moving stream of solar wind, a subsiding tremor of magnetic activity sparked bright auroras over Abisko, Sweden. David Williams witnessed the display as it emerged over the crest of Mt. Nouljia:
"Our Lights Over Lapland tour group arrived at the Aurora Sky Station at about 10pm," says Williams. "No sooner had we set up our cameras when these intense auroras formed apparently just up the mountainside."
Now the onlookers of that amazing display are wondering, when will it happen again? As Earth exits one stream of solar wind, another is on the way. Estimated time of arrival: Dec. 10th or 11th. The stream of gaseous material is flowing from a canyon-shaped hole in the sun's atmosphere stretching down from the sun's north pole. Minor geomagnetic storms and bright Arctic auroras are possible when the solar wind arrives.
ATMOSPHERIC RADIATION IS INCREASING: Since the spring of 2015, Spaceweather.com and the students of Earth to Sky Calculus have been flying balloons to the stratosphere over California to measure cosmic rays. Soon after our monitoring program began, we quickly realized that radiation levels are increasing. Why? The main reason is the solar cycle. In recent years, sunspot counts have plummeted as the sun's magnetic field weakens. This has allowed more cosmic rays from deep space to penetrate the solar system. As 2017 winds down, our latest measurements show the radiation increase continuing apace--with an interesting exception, circled in yellow:
In Sept. 2017, the quiet sun surprised space weather forecasters with a sudden outburst of explosive activity. On Sept. 3rd, a huge sunspot appeared. In the week that followed, it unleashed the strongest solar flare in more than a decade (X9-class), hurled a powerful CME toward Earth, and sparked a severe geomagnetic storm (G4-class) with Northern Lights appearing as far south as Arkansas. During the storm we quickened the pace of balloon launches and found radiation dropping to levels we hadn't seen since 2015. The flurry of solar flares and CMEs actually pushed some cosmic rays away from Earth.
Interestingly, after the sun's outburst, radiation levels in the stratosphere took more than 2 months to fully rebound. Now they are back on track, increasing steadily as the quiet sun resumes its progress toward Solar Minimum. The solar cycle is not expected to hit rock bottom until 2019 or 2020, so cosmic rays should continue to increase, significantly, in the months and years ahead. Stay tuned for updates as our balloons continue to fly.
Technical note: The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies, which span the range of medical X-ray machines and airport security scanners, trace secondary cosmic rays, the spray of debris created when primary cosmic rays from deep space hit the top of Earth's atmosphere.
Realtime Space Weather Photo Gallery
FAR OUT CHRISTMAS GIFTS: Helium doesn't pay for itself. That's why the students of Earth to Sky Calculus fly cool things to the edge of space on board their cosmic ray balloons--so you can buy them in our Christmas Store:
Crystal balls, solar eclipse pendants, pyramids, pickles and much more: they've all been to the edge of space and back, and they all make great holiday gifts. Every dollar spent in the store supports STEM education and high-altitude space weather research. Shop now!
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education