The Two Faced Moon

The moon is "tidally locked" to Earth, meaning only one hemisphere faces us. We know that side well, with its dark regions called maria, or "seas," of cooled magma. Oddly, however, these maria are virtually absent from the back side of the moon, as has been revealed to us by probes (and seen in person by Apollo 8 astronauts). The proverbial "dark side of the moon" also is much more

 pockmarked by craters.

The starkly different hemispheres have been partly explained by the far side having a crust roughly 9 miles (15 kilometers) thicker than that of the near side. The crust on the side facing us could have more easily cracked under the onslaught of meteorites, causing maria-forming magma to be released from deeper in the moon. But that crustal asymmetry is an enigma itself

Witch's Broom

This image of a supernova remnant called the Witch's Broom received high commendation in the Deep Space category. It shows scattering debris from a Milky Way star that exploded several thousand years ago. These cosmic filaments are part of the Veil Nebula, one of the largest supernova remnants in the sky. It lies some 1,400 light-years away in the constellation Cygnus.