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.
Image courtesy STEREO/ESA/NASA
A lighthouse in northern Norway is illuminated by the green glow of northern lights dancing in the skies above Narvick, Norway, on March 20.
Comet Pan-STARRS appears almost lost in the ghostly glow, seen with its tiny fuzzy tail in the above image, near the horizon just to the left of the lighthouse base.
The colorful stellar nursery known as the Lagoon nebula is captured through a backyard telescope on August 1.
Located some 5,000 light-years from Earth in the southern constellation Sagittarius, this giant cloud of gas and dust stretches some 100 light-years across and is faintly visible with the naked eye from dark locations.