March 6, 2019
Your birthday is not just a date on a calendar. It is the yearly return of a moment when the universe became more observant, more feeling,...
A February without Sunspots
Birthday · March 6, 2019
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APOD published March 6, 2019. Credit: Alan Friedman (Averted Imagination). A publication-date match, not a photo taken on your date. Independent of NASA.
Where have all the sunspots gone? Last month the total number of spots that crossed our Sun was ... zero. Well below of the long term monthly average, the Sun's surface has become as unusually passive this solar minimum just like it did 11 years ago during the last solar minimum. Such passivity is not just a visual spectacle, it correlates with the Sun being slightly dimmer, with holes in the Sun's corona being more stable, and with a reduced intensity in the outflowing solar wind. The reduced wind, in turn, cools and collapses Earth's outer atmosphere (the thermosphere), causing reduced drag on many Earth-orbiting satellites. Pictured in inverted black & white on the left, the Sun's busy surface is shown near solar maximum in 2012, in contrast to the image on the right, which shows the Sun's surface last August, already without spots (for a few days), as solar minimum was setting in. Effects of this unusually static solar minimum are being studied.
Image credit: Alan Friedman (Averted Imagination)