Beautiful island universe M94 lies a mere 15 million light-years distant in the northern constellation of the hunting dogs, Canes Venatici . A popular target for earth-based astronomers , the face-on spiral galaxy is about 30,000 light-years across. Its remarkable features include prominent dust lanes, a bright, point-like nucleus, and a bright, bluish ring dominated by the light of young, massive stars. The massive stars in the ring are all likely less than 10 million years old, indicating the galaxy experienced a well-defined era of rapid star formation. As a result, while the small, bright nucleus is typical of the Seyfert class of active galaxies, M94 is also known as a starburst galaxy . Because M94 is relatively nearby, astronomers can explore in detail reasons for the galaxy's burst of star formation.

These are galaxies of the Hercules Cluster , an archipelago of island universes a mere 500 million light-years away . Also known as Abell 2151, this cluster is loaded with gas and dust rich, star-forming spiral galaxies but has relatively few elliptical galaxies, which lack gas and dust and the associated newborn stars. The colors in this remarkably deep composite image clearly show the star forming galaxies with a blue tint and galaxies with older stellar populations with a yellowish cast. The sharp picture spans about 3/4 degree across the cluster center, corresponding to over 6 million light-years at the cluster's estimated distance. In the cosmic vista many galaxies seem to be colliding or merging while others seem distorted - clear evidence that cluster galaxies commonly interact. In fact, the Hercules Cluster itself may be seen as the result of ongoing mergers of smaller galaxy clusters and is thought to be similar to young galaxy clusters in the much more distant, early Universe .

The Chameleon is a small constellation near the south celestial pole . Boasting no bright stars , it blends inconspicuously with the starry southern sky. But, taken in dark skies over Namibia, this image reveals a stunning aspect of the shy constellation -- a field of dusty nebulae and colorful stars. Blue reflection nebulae are scattered through the scene, but most eye-catching is the complex of silvery dust clouds that only faintly reflect starlight, punctuated by dense dark nebulae . The dark nebulae stand out because they block out background stars. This view of the cosmic dust clouds spans about 4 degrees on the sky.

Earth's Moon and planet Jupiter made a beautiful pairing in the night sky late last week. This skyscape recorded on July 11 from Brittany in north western France captures the bright conjunction through a cloud bank. The clouds add drama and mystery to the scene but they were also positioned to reduce the intense moonlight. As a result, the exposure captures Jupiter's own Galilean moons (lower right) as tiny pinpricks of light, lined up and hugging both sides of the solar system's ruling gas giant . Later this week, the Moon is headed for a conjunction with Mars and Venus in the dawn sky.

A volcano on Krakatoa is still erupting. Perhaps most famous for the powerfully explosive eruption in 1883 that killed tens of thousands of people, ash from a violent eruption might also have temporarily altered Earth's climate as long as 1500 years ago. In 1927, eruptions caused smaller Anak Krakatau to rise from the sea, and the emerging volcanic island continues to grow at an average rate of 2 cm per day. The latest eruption of Anak Krakatau started in 2008 April and continues today. In this picture , Anak Krakatau is seen erupting from Rakata , the main island of the Krakatoai group. High above, stars including the Big Dipper are clearly apparent.

If Earth received this message from deep space , could we decode it? The people from the Cosmic Call project sent the above image as the first page of a longer message. The message was broadcast toward local stars by radio telescope during the summer of 1999. Another message was sent in 2003. The single-dish, 70-meter diameter telescope that send the messages is located in Ukraine on the Crimean peninsula near the town of Yevpatoria . This first page of the Cosmic Call 1999 message, shown above, involves only numbers and so is easier for puzzle solvers to decode than a more famous message broadcast toward distant star cluster M13 in 1974. (The solution is here .)

Noctilucent or night-shining clouds lie near the edge of space . From about 80 kilometers above Earth's surface, the icy clouds can still reflect sunlight even though the Sun itself is below the horizon as seen from the ground . Usually occurring at high latitudes in summer months, the diaphonous apparitions are also known as polar mesospheric clouds and may be connected to global change in the lower atmosphere. This impressive 360 degree panorama made from 34 separate images captures an impressive display of noctilucent clouds all over the sky. It was recorded last month from Vallentuna, Sweden. The photographer reports that the display was like a noctilucent cloud storm, one of the best he's ever witnessed .

What lights up this castle of star formation? The familiar Eagle Nebula glows bright in many colors at once. The above image is a composite of three of these glowing gas colors. Pillars of dark dust nicely outline some of the denser tower s of star formation . Energetic light from young massive stars causes the gas to glow and effectively boils away part of the dust and gas from its birth pillar. Many of these stars will explode after several million years, returning most of their elements back to the nebula which formed them. This process is forming an open cluster of stars known as M16 .

Born in supernovae, pulsars are spinning neutron stars, collapsed stellar cores left from the death explosions of massive stars. Traditionally identified and studied by observing their regular radio pulsations , two dozen pulsars have now been detected at extreme gamma-ray energies by the Fermi Gamma-ray Space Telescope . The detections include 16 pulsars identified by their pulsed gamma-ray emission alone. This gamma-ray all-sky map, aligned with the plane of our Milky Way Galaxy, shows the pulsar positions, with the 16 new Fermi pulsars circled in yellow (8 previously known radio pulsars are in magenta). Bizarre stellar corpses, the Vela , Crab, and Geminga pulsars on the right are the brightest ones in the gamma-ray sky. Pulsars Taz, Eel, and Rabbit are named for the nebulae they are now known to power . The Gamma Cygni and CTA 1 pulsars at the left also reside within expanding supernova remnants of the same name.

Connecting the Pipe Nebula to the colorful regon near bright star Antares is a dark cloud dubbed the Dark River , flowing from the picture's left edge. Murky looking, the Dark River 's appearance is caused by dust obscuring background starlight, although the dark nebula contains mostly hydrogen and molecular gas. Surrounded by dust, Antares , a red supergiant star, creates an unusual bright yellowish reflection nebula. Above it, bright blue double star Rho Ophiuchi is embedded in one of the more typical bluish reflection nebulae, while red emission nebulae are also scattered around the region. Globular star cluster M4 is just seen above and right of Antares, though it lies far behind the colorful clouds, at a distance of some 7,000 light-years. The Dark River itself is about 500 light years away. The colorful skyscape is a mosaic of telescopic images spanning nearly 10 degrees (20 Full Moons) across the sky in the constellation Scorpius.