Resembling a fiery blue marble, the sun is captured in this dramatic extreme-ultraviolet-light image by NASA's STEREO spacecraft on September 27.

While the sun is at its maximum level of activity on its 11-year sunspot cycle, its surface the past month appears strangely quiet, with few solar storms and nearly no brighter active regions.

Astronomers theorize that this solar cycle's maximum may in fact be a double peak and that we are between peaks now. They also think that both sunspot and storm activity may pick up later this fall or in the winter early next year.

—Andrew Fazekas