An Galaxy Edge On - NGC 891

Galaxy NGC 891, or Caldwell 23, is an edge-on unbarred spiral galaxy about 30 million light-years away in the constellation Andromeda. It was discovered by William Herschel on October 6, 1784. The galaxy is a member of the NGC 1023 group of galaxies in the Local Supercluster.

NGC 891 looks as we think the Milky Way would look like when viewed edge-on (some astronomers have even noted how similar to NGC 891 our galaxy looks as seen from the Southern Hemisphere) and in fact both galaxies are considered very similar in terms of luminosity and size; studies of the dynamics of its molecular hydrogen have also proven the likely presence of a central bar. Despite this, recent high-resolution images of its dusty disk show unusual filamentary patterns. These patterns are extending into the halo of the galaxy, away from its galactic disk. Scientists presume that supernova explosions caused this interstellar dust to be thrown out of the galactic disk toward the halo.

Credit: NASA/ESA/Hubble

A Total Lunar Eclipse over Tajikistan

Credit: Jean-Luc Dauvergne (Ciel et Espace); Music: Valère Leroy & Sophie Huet (Space-Music)

If the full Moon suddenly faded, what would you see? The answer during the total lunar eclipse of 2011 June was recorded in a dramatic time lapse video from Tajikistan. During a total lunar eclipse, the Earth moves between the Moon and the Sun, causing the moon to fade dramatically. The Moon never gets completely dark, though, since the Earth’s atmosphere refracts some light. As the above video begins, the scene may appear to be daytime and sunlit, but actually it is a nighttime and lit by the glow of the full Moon. As the moon becomes eclipsed and fades, the wind dies down and background stars can be seen reflected in foreground lake. Most spectacularly, the sky surrounding the eclipsed moon suddenly appears to be full of stars and highlighted by the busy plane of our Milky Way Galaxy. The sequence repeats with a closer view, and the final image shows the placement of the eclipsed Moon near the EagleSwanTrifid, and Lagoon nebulas. Nearly two hours after the eclipse started, the moon emerged from the Earth’s shadow and its bright full glare again dominated the sky.