Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2013 May 20
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Blue Sun Bursting
Image Credit & Copyright: Alan Friedman (Averted Imagination)

Explanation: 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 colour 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 colour-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 aurorae.

Tomorrow's picture: space rectangle


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