THE SOLAR WIND HAS ARRIVED: As predicted, today Earth is entering a stream of high-speed solar wind. Flowing from a canyon-shaped hole in the sun's atmosphere, the stream could affect our planet for at least the next two days. Arctic sky watchers should be alert for auroras on Feb.16-17. Free: Aurora alerts.
NEUTRONS IN THE STRATOSPHERE: In a joint operation on Feb.12th, Spaceweather.com, the students of Earth to Sky Calculus, and their sister club Earth to Sky Maritime, launched a neutron counter to the stratosphere onboard a high altitude balloon. Neutrons are an important form of cosmic radiation because they provide much of the biologically effective radiation dose at altitudes of interest to aviation and space tourism. How are these particles distributed through our atmosphere? This is what we wanted to find out.
We've just finished reducing the data and can report that the experiment was a success. Neutrons were detected throughout the 2 hour flight covering altitudes from ground level to 113,200 ft:
This first data set shows that neutrons, like gamma rays, peak at the entrance to the stratosphere in a layer known as the Regener-Pfotzer Maximum. Moreover, neutron counts are significantly elevated not only in the stratosphere, but also at lower altitudes where planes fly (20,000 ft to 45,000 ft)--something to think about the next time you buy an airline ticket.
We've been monitoring cosmic rays in the atmosphere for more than two years, and find that deep space radiation has been intensifying. Previous payloads measured only X-rays and gamma-rays, however. The addition of a neutron counter to the payload is a major upgrade, providing a more complete picture of the radiation environment. Stay tuned for updates as we improve our technique and gather more data in future flights.
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EARTH ECLIPSES THE SUN: On Valentine's Day, Feb. 14th, NASA's Solar Dynamics Observatory witnessed an eclipse of the sun -- by our very own planet. Earth passed directly between the spacecraft and the solar disk, producing a near-total blackout:
This event marks the beginning of eclipse season for SDO. Twice a year, in the weeks leading up to the equinoxes, Earth can pass directly between the sun and SDO. This is the "spring season." Between now and mid-March, these eclipses will repeat once a day around 07:30 UT.
At the beginning of the season, eclipses are short, only a few minutes long. Their duration increases to 72 minutes, mid-season, before tapering off to minutes again as the season winds down. Because most eclipses are relatively short, there is still plenty of uninterrupted time for SDO to monitor activity on the sun. Researchers estimate a scant 2% data loss averaged over the weeks ahead.