May 20, 2013
On your birthday, photons that left distant stars before humans walked the Earth finally completed their journey. You began yours.
Blue Sun Bursting
Birthday · May 20, 2013
A little universe, just for you
Your date.
Ready to give.
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APOD published May 20, 2013. Credit: Alan Friedman. A publication-date match, not a photo taken on your date. Independent of NASA.
Our Sun is not a giant blueberry. Our Sun can be made to appear similar to the diminutive fruit, however, by imaging it in a specific color of extreme violet light called CaK that is emitted by the very slight abundance of ionized Calcium in the Sun's atmosphere, and then false color-inverting the image. This solar depiction is actually scientifically illuminating as a level of the Sun's chromosphere appears quite prominent, showing a crackly textured surface, cool sunspots appearing distinctly bright, and surrounding hot active regions appearing distinctly dark. The Sun is currently near the maximum activity level in its 11 year cycle, and has emitted powerful flares over the past week. During times of high activity, streams of energetic particles from Sun may impact the Earth's magnetosphere and set off spectacular auroras.
Image credit: Alan Friedman