NASA Astronomy Picture of the Day:

Why would clouds form a hexagon on Saturn? Nobody is sure. Originally discovered during the Voyager flybys of Saturn in the 1980s, nobody has ever seen anything like it anywhere else in the Solar System. Acquiring its first sunlit views of far northern Saturn in late 2012, the Cassini spacecraft's wide-angle camera recorded this stunning, false-color image of the ringed planet's north pole. The composite of near-infrared image data results in red hues for low clouds and green for high ones, giving the Saturnian cloudscape a vivid appearance. This and similar images show the stability of the hexagon even 20+ years after Voyager. Movies of Saturn's North Pole show the cloud structure maintaining its hexagonal structure while rotating. Unlike individual clouds appearing like a hexagon on Earth, the Saturn cloud pattern appears to have six well defined sides of nearly equal length. Four Earths could fit inside the hexagon. Beyond the cloud tops at the upper right, arcs of the planet's eye-catching rings appear bright blue.

NASA Astronomy Picture of the Day:

A sensitive video camera on a summit of the Vosges mountains in France captured these surprising fireworks above a distant horizon on June 26. Generated over intense thunderstorms, this one about 260 kilometers away, the brief and mysterious flashes have come to be known as red sprites. The transient luminous events are caused by electrical breakdown at altitudes of 50 to 100 kilometers. That puts them in the mesophere, the coldest layer of planet Earth's atmosphere. The glow beneath the sprites is from more familiar lighting though, below the storm clouds. But on the right, the video frames have captured another summertime apparition from the mesophere. The silvery veins of light are polar mesospheric clouds. Also known as noctilucent or night shining clouds, the icy clouds still reflect the sunlight when the Sun is below the horizon.

Photo by Stephane Vetter

NASA Astronomy Picture of the Day:

Stars are forming in Lynds Dark Nebula (LDN) 1251. About 1,000 light-years away and drifting above the plane of our Milky Way galaxy, the dusty molecular cloud is part of a complex of dark nebulae mapped toward the Cepheus flare region. Across the spectrum, astronomical explorations of the obscuring interstellar clouds reveal energetic shocks and outflows associated with newborn stars, including the telltale reddish glow from scattered Herbig-Haro objects seen in this sharp image. Distant background galaxies also lurk on the scene, buried behind the dusty expanse. This alluring view imaged with a backyard telescope and broadband filters spans about two full moons on the sky, or 17 light-years at the estimated distance of LDN 1251.

Photo by Ara Jerahian

NASA Astronomy Picture of the Day:

The Old Astronomer's Milky Way arcs through this peaceful northern sky. Against faint, diffuse starlight you can follow dark rifts of interstellar dust clouds stretching from the galaxy's core. They lead toward bright star Antares at the right, almost due south above the horizon. The brightest beacon in the twilight is Jupiter, though. From the camera's perspective it seems to hang from the limb of a tree framing the foreground, an apple tree of course. The serene maritime nightscape was recorded in tracked and untracked exposures on June 16 from Dover, Nova Scotia, planet Earth.

Photo by Kristine Richer

NASA Astronomy Picture of the Day:

Has your world ever turned upside-down? It would happen every day if you stay fixed to the stars. Most time-lapse videos of the night sky show the stars and sky moving above a steady Earth. Here, however, the camera has been forced to rotate so that the stars remain fixed, and the Earth rotates around them. The movie, with each hour is compressed to a second, dramatically demonstrates the daily rotation of the Earth, called diurnal motion. The video begins by showing an open field in Namibia, Africa, on a clear day, last year. Shadows shift as the Earth turns, the shadow of the Earth rises into the sky, the Belt of Venus momentarily appears, and then day turns into night. The majestic band of our Milky Way Galaxy stretches across the night sky, while sunlight-reflecting, Earth-orbiting satellites zoom by. In the night sky, you can even spot the Large and Small Magellanic Clouds. The video shows a sky visible from Earth's Southern Hemisphere, but a similar video could be made for every middle latitude on our blue planet. Almost Hyperspace: Random APOD Generator

Video by BartoszWojczyński

NASA Astronomy Picture of the Day:

What created this unusual planetary nebula? NGC 7027 is one of the smallest, brightest, and most unusually shaped planetary nebulas known. Given its expansion rate, NGC 7027 first started expanding, as visible from Earth, about 600 years ago. For much of its history, the planetary nebula has been expelling shells, as seen in blue in the featured image. In modern times, though, for reasons unknown, it began ejecting gas and dust (seen in red) in specific directions that created a new pattern that seems to have four corners. These shells and patterns have been mapped in impressive detail by recent images from the Wide Field Camera 3 onboard the Hubble Space Telescope. What lies at the nebula's center is unknown, with one hypothesis holding it to be a close binary star system where one star sheds gas onto an erratic disk orbiting the other star. NGC 7027, about 3,000 light years away, was first discovered in 1878 and can be seen with a standard backyard telescope toward the constellation of the Swan (Cygnus).

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NASA Astronomy Picture of the Day:

When the lake calmed down, many wonders of the land and sky appeared twice. Perhaps the most dramatic from the dark sky was the central band of our Milky Way Galaxy, visible as a diagonal band. Toward the right were both the Small (SMC) and Large (LMC) Magellanic Clouds, satellite galaxies of our Milky Way. Faint multicolored bands of airglow fanned across the night. Numerous bright stars were visible including Antares, while the bright planet Jupiter appears just above the image center. The featured image is a composite of exposures all taken from the same camera and from the same location within 30 minutes in mid-May from the shore of Lake Bonney Riverland in South Australia. Dead trees that extend from the lake were captured not only in silhouette, but reflection, while lights from the small town of Barmera were visible across the lake. In July, Jupiter and Saturn will rise toward the east just as the Sun sets in the west.

Photo by Will Godward