SOLAR WIND STORM: The solar wind around Earth is blowing faster than 650 km/s--an electrified gale that is sparking G1 and G2-class geomagnetic storms on Sept 16th. High latitude sky watchers should be alert for auroras after local nightfall. Free: Aurora Alerts
MORNING PLANETS ALIGN: Set your alarm for dawn. Three planets and the crescent Moon are gathering for a beautiful alignment before sunrise. Alan Dyer sends this preview from Gleichen, Alberta:
"This was the view on the morning of Sept. 12th, of Venus, Mercury (then at greatest elongation from the Sun) and Mars in the dawn sky, along with the star Regulus." says Dyer. "With Earth in the picture, this was an image of all four rocky terrestrial planets in one frame!"
In the mornings ahead, the crescent Moon will join the show, hopping from one planet to the next. Venus and the Moon will look especially lovely together on Sept. 17th and 18th, while on the 19th and 20th Venus and Regulus pass one another less than 1 degree apart. Look east before sunrise and enjoy the show! Sky maps: Sept. 17, 18, 19, 20.
Realtime Space Weather Photo Gallery
PHYSICS OF AN EXPLODING SPACE WEATHER BALLOON: This month, the students of Earth to Sky Calculus have been launching space weather balloons at a frenetic pace, more than half a dozen so far. Their goal: To monitor the effect of September's surprising solar flares on Earth's upper atmosphere. At the apex of every flight, the balloon explodes and the payload parachutes back to Earth. On Sept. 13th, a new upward-facing camera photographed the pop:
This image illustrates recent findings about the physics of exploding balloons. In Oct. 2015, researchers Sébastien Moulinet and Mokhtar Adda-Bedia of the Ecole Normale Supérieure published a Physical Review Letter entitled "Popping Balloons: A Case Study of Dynamical Fragmentation." In it, they reported the results of a series of fun yet informative laboratory experiments in which one balloon after another was popped and analyzed.
Basically, there are two ways a balloon can pop: along a single seam (the "opening regime") or along many tears (the "fragmentation regime"). This video shows the two regimes in action. Which way the balloon decided to pop depends on the stress in the rubber membrane. When the stress is low, it can be relieved with a single tear, but when the stress is high, many tears are required to do the job.
Clearly, space weather balloons explode in the fragmentation regime. This is hardly a surprise. When space weather balloons are launched, they measure no more than 6 to 8 feet in diameter. By the time they reach the stratosphere, they have stretched into a sphere as wide as a house. That's a lot of tension to release! More information about this research is available from the American Physical Society.
ROSE QUARTZ CRYSTAL ECLIPSE PENDANTS: On Aug. 21st during the Great American Solar Eclipse, the students of Earth to Sky Calculus launched 11 space weather balloons from the path of totality. They aimed to photograph the Moon's shadow from the stratosphere--and they succeeded. As a fundraiser, some of the balloons carried jewelry. Here is a rose quartz crystal pendant entering the Moon's shadow more than 90,000 feet above the Malheur National Forest in eastern Oregon:
During the 2.5 hour flight, the pendants were wrapped in the Moon's shadow for more than two minutes, experiencing a spooky darkness colder than -50 C.
You can have one for $149.95. Each crystal pendant comes with a unique gift card showing the jewelry passing through the Moon's shadow and floating at the top of Earth's atmosphere. The interior of the card tells the story of the flight and confirms that this gift has been to the edge of space and back again.
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education