NEUTRONS ON A PLANE: Want to experience space weather? It's easy. Just step on board an airplane. Cosmic rays from deep space penetrate Earth's atmosphere where air travelers absorb them during long trips. On March 9th, the students of Earth to Sky Calculus flew to Sweden for an Arctic space weather balloon launch. During the flight from Los Angeles to Stockholm, they used a bubble chamber to search for neutrons--and they found them. In this photo, each bubble (three are circled for illustration) shows where a neutron passed through the chamber and vaporized a superheated droplet:
Among researchers it is well known that neutrons are an important form of cosmic rays, providing much of the biologically effective radiation dose at altitudes of interest to aviation and space tourism. Low-energy neutrons also cause single-event upsets in aircraft avionics.
By counting the bubbles in the chamber, it is possible to estimate the total dose of neutron radiation during our flight. The answer is 18 uSv--even more than the dose of X-rays and gamma-rays, which the students also measured. Lesson: When measuring aviation radiation, don't forget the neutrons! Stay tuned for more results from our ongoing research trip to the Arctic Circle.
Realtime Space Weather Photo Gallery
SOMETHING SPECIAL ABOUT MARCH: If you feel like March has been a good month for auroras ... you're right. According to 75 years of historical records analyzed by solar physicist David Hathaway, the months around equinoxes are almost twice as likely as solstices to have geomagnetic disturbances. Indeed, according to this plot, March may be the best month of the year for Arctic auroras:
Photo credit: Caroline/AdventureMutzz of Ersfjordbotn, Norway. Mar. 8, 2017
Researchers have long known that auroras favor equinoxes, but they didn't fully understand why until NASA launched the THEMIS satellites 10 years ago. In 2007, THEMIS detected magnetic 'ropes' occasionally connecting Earth's upper atmosphere directly to the sun. Solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras.
It turns out that rope-like magnetic connections between the sun and Earth are favored in spring and fall. It's a matter of geometry: As Earth goes around in its orbit, Earth's tilted magnetic poles make different angles with respect to the Sun, tipping back and forth with a one-year cadence. Around the time of the equinoxes, Earth's magnetic field is best oriented for "connecting-up" with the sun.
Northern spring is coming. Arctic sky watchers, enjoy the green!
NORTHERN LIGHTS SPACE PENDANT: To raise money for their trip to the Arctic Circle, on March 2nd the students of Earth to Sky Calculus flew a payload-full of Northern Lights pendants to the edge of space above California. You can have one for $69.95. Each piece of jewelry comes with a greeting card telling the story of the pendant's trip to the stratosphere and certifying its peak altitude: 112,200 feet above Earth's surface.
Bonus: Would you like your pendant to fly above the Arctic Circle as well? Make a note in the COMMENTS box at checkout and we will take your pendant to Sweden for a second trip to the stratosphere.
More far-out gifts may be found in the Earth to Sky Store. All proceeds support STEM education and high-altitude ballooning.
Realtime Space Weather Photo Gallery