#PencilNebula | This shock wave plows through space at over 500,000 kilometers per hour. Moving toward to bottom of this beautifully detailed color composite, the thin, braided filaments are actually long ripples in a sheet of glowing gas seen almost edge on. About 5 light-years long and a mere 800 light-years away, the Pencil Nebula is only a small part of the #VelaSupernovaRemnant.
'Proctor Crater, Mars' | This view from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter is of the Proctor Crater. The relatively bright, small ridges are ripples. From their study on Earth, and close-up examination by the MER rovers, scientists surmise that the ripples are composed of fine sand.