The shortest day of the year has come and gone and the countdown to summer (in the Northern Hemisphere) has begun. From a day length of 6 hours 15 minutes yesterday the next 183 days will see the length of the day – at this latitude – increasing by an average of over 3 minutes every day reaching a day length of almost 17 hours at the summer solstice.
At 11:12 UT (6:12 a.m. EST), the world didn’t end (as far as I can tell), but it was a significant time none-the-less. That was the exact minute of the Winter Solstice in the Northern Hemisphere (or the Summer Solstice in the Southern Hemisphere) — when the daylight hours are shortest and the sun reaches its most southern position in the sky at noon.
The sun at solstice 12:12 CET on 21.12.2012: image NASA
NASA Solar Dynamics Observatory (SDO) captured the time of solstice from orbit. Although the SDO is always imaging the sun through a multitude of filters, this is a great excuse to showcase the fantastic beauty of our nearest star, while putting all the doomsday nonsense behind us.
The sun didn’t unleash a killer solar flare or devastating coronal mass ejection, but it is undergoing a fascinating period in its solar cycle.
As can be seen from the SDO image above, the solar magnetic field is twisted and warped, channeling million-degree plasma high into the sun’s atmosphere in the form of beautiful coronal loops. This is all because the sun is fast approaching “solar maximum” — an exciting time when the sun’s magnetic field is most stressed.
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