June 29, 2015
Long before your first heartbeat, stars were busy forging the elements you would one day call your own.
Sunspot Group AR 2339 Crosses the Sun
Birthday · June 29, 2015
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APOD published June 29, 2015 · Video still. Credit: Stanislav Korotkiy (AstroAlert) & Mikhail Chubarets; Music: Pas de Deux (Bird Creek). A publication-date match, not a photo taken on your date. Independent of NASA.
How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent a few weeks ago as the active region AR 2339 came around the limb of the Sun and was tracked for the next 12 days by NASA's Solar Dynamic Observatory. In the featured time lapse video, some sunspots drift apart, while others merge. All the while, the dark central umbral regions shift internally and their surrounding lighter penumbras shimmer and wave. The surrounding Sun appears to flicker as the carpet of yellow granules come and go on the time scale of hours. In general, sunspots are relatively cool regions where the local magnetic field pokes through the Sun's surface and inhibits heating. Over the past week, an even more active region -- AR 2371 -- has been crossing the Sun and releasing powerful flares that have resulted in impressive auroras here on Earth. Follow APOD on: Facebook, Google Plus, or Twitter
Image credit: Stanislav Korotkiy (AstroAlert) & Mikhail Chubarets; Music: Pas de Deux (Bird Creek)