Nasa Astronomy Pictures, Good astronomy pictures from Nasa

 
Although the phase of this moon might appear familiar, the moon itself might not. In fact, this gibbous phase shows part of Jupiter's moon Europa. The robot spacecraft Galileo captured this image mosaic during its mission orbiting Jupiter from 1995 - 2003. Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt. Raised terrain is particularly apparent near the terminator, where it casts shadows. Europa is nearly the same size as Earth's Moon, but much smoother, showing few highlands or large impact craters. Evidence and images from the Galileo spacecraft, indicated that liquid oceans might exist below the icy surface.

If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe of about 100 billion stars, 32 million light-years away toward the constellation Pisces, M74 presents a gorgeous face-on view. Classified as an Sc galaxy, the grand design of M74's graceful spiral arms are traced by bright blue star clusters and dark cosmic dust lanes.

This cosmic expanse of dust, gas, and stars covers some 4 degrees on the sky in the heroic constellation Perseus. Centered in the gorgeous skyscape is the dusty blue reflection nebula NGC 1333, about 1,000 light-years away. At that estimated distance, the field of view is nearly 70 light-years across. Other reflection nebulae are scattered around, along with remarkable dark dust nebulae and the faint reddish glow of hydrogen gas. These dust and gas clouds lie near the edge of a large molecular cloud.

Last August, the Space Shuttle Endeavour crew captured this shot of the International Space Station (ISS) against the backdrop of Planet Earth. During that trip to the ISS, the space shuttle crew re-supplied the station, repaired the station, and even built more of the station. Its primary mission complete, the crew took the premier spaceship on a tour around the premier space station. Pictured during this inspection tour, the ISS is visible in front the Ionian Sea. The boot of Italy is visible on the left, while the western coastlines of Greece and Albania stretch across the top.

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size. When the Sun is in the right position and mostly hidden by thick clouds, these thinner clouds significantly diffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts.

This wide, sharp telescopic view reveals galaxies scattered beyond the stars near the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan's Quintet.

Braided, serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun, as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers.

The spherical coma of Comet Holmes has swollen to a diameter of over 1.4 million kilometers, making the tenuous, dusty cloud even bigger than the Sun. Scattering sunlight, all that dust and gas came from the comet's remarkably active nucleus, whose diameter before the late October outburst was estimated to be a mere 3.4 kilometers. In this sharp image, recorded on November 14 with the Canada-France-Hawaii Telescope, stars are easily visible right through the outer coma, while the nucleus is buried inside the condensed, bright region.

Some auroras can only be seen with a camera. They are called sub-visual and are too faint to be seen with the unaided eye. The reason is that the human eye only accumulates light for a fraction of a second at a time, while a camera shutter can be left open indefinitely. When photographing an already picturesque scene above Juneau, Alaska, USA, a camera caught green sub-visual aurora near the horizon. Auroras are sparked by energetic particles from the Sun impacting the magnetic environment around the Earth. Resultant energetic particles such as electrons and protons rain down near the Earth's poles and impact the air.

What does the Earth look like from the Moon? A new version of this space age perspective was captured by the robotic Kaguya spacecraft currently in orbit around Earth's Moon. Launched two months ago by Japan, the scientific mission of the Selenological and Engineering Explorer (SELENE), nicknamed Kaguya, is to study the origin and evolution of the Moon. Last month Kaguya reached lunar orbit and starting transmitting data and images. This frame is from Kaguya's onboard HDTV camera.

Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters. The Pleiades contains over 3000 stars, is about 400 light years away, and only 13 light years across. Quite evident in the above photograph are the blue reflection nebulae that surround the brighter cluster stars. Low mass, faint, brown dwarfs have also been found in the Pleiades.

With pine trees in dim silhouette, this skyscape from Breil-sur-Roya in southern France was captured on November 11. In the early evening scene, a satellite seems to streak through the branches, while bright, round, fuzzy Comet Holmes appears to lie just beyond them, near the stars of the constellation Perseus. Mirfak, alpha star of Perseus, is the brightest star above the comet and to the right. Next Monday (November 19), Holmes will be close enough to Mirfak to view the star through the remarkable comet's expanding coma. Recent measurements place the dusty coma's diameter at about 1.4 million kilometers, even larger than the Sun.