The Waterfall and the World at Night

Image Credit & Copyright: Stéphane Vetter (Nuits sacrées)

Explanation: Above this boreal landscape, the arc of the Milky Way and shimmering aurorae flow through the night. Like an echo, below them lies Iceland's spectacular Godafoss, the Waterfall of the Gods. Shining just below the Milky Way, bright Jupiter is included in the panoramic nightscape recorded on March 9. Faint and diffuse, the Andromeda Galaxy (M31) appears immersed in the auroral glow. The digital stitch of four frames is a first place winner in the 2013 International Earth and Sky Photo Contest on Dark Skies Importance organized by The World at Night. An evocative record of the beauty of planet Earth's night sky, all the contest's winning entries are featured in this video.

Milky Way Over Crater Lake with Airglow

Image Credit & Copyright: John H. Moore; Annotation: Judy Schmidt

Explanation: How many different astronomical phenomena have come together to create the above vista? Several. First, in the foreground, is Crater Lake -- a caldera created by volcanism on planet Earth about 7,700 years ago. Next, inside the lake, is water. Although the origin of the water in the crater is melted snowfall, the origin of water on Earth more generally is unclear, but possibly related to ancient Earthly-impacts of icy bodies. Next, the green glow in the sky is airglow, light emitted by atoms high in the Earth's atmosphere as they recombine at night after being separated during the day by energetic sunlight. The many points of light in the sky are stars, glowing by nuclear fusion. They are far above the atmosphere but nearby to our Sun in the Milky Way Galaxy. Finally, the bright arch across the image is the central band of the Milky Way, much further away, on the average, than the nearby stars, and shaped mostly by gravity. Contrary to appearances, the Milky Way band glows by itself and is not illuminated by the airglow. The above image is a six-frame panorama taken during about two weeks ago in Oregon, USA.

Stars and Lightning Over Greece

Image Credit & Copyright: Bill Metallinos

Explanation: It may appear, at first, like the Galaxy is producing the lightning, but really it's the Earth. In the foreground of the above picturesque nighttime landscape is the Greek Island of Corfu, with town lights surrounding Lake Korrision. Visible farther in the distance are lights from the town of Preveza on the Greek mainland. In the more distant sky a thunderstorm is threatening, with two lightning strokes caught together during this 45 second wide-angle exposure taken in mid-May. The lightning branch on the left appears to be striking near Preveza, whereas the lightning strike on the right appears to be striking near Mount Ainos on the Greek Island of Cephalonia. Much farther in the distance, strewn about the sky, are hundreds of stars in the neighborhood of our Sun in the Milky Way Galaxy. Furthest away, arching over the entire panorama, are billions of stars that together compose the central band of our Milky Way.

A Hole in Mars

Image Credit: NASA, JPL, U. Arizona

Explanation: What created this unusual hole in Mars? The hole was discovered by chance in 2011 on images of the dusty slopes of Mars' Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. The hole appears to be an opening to an underground cavern, partly illuminated on the image right. Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep. Why there is a circular crater surrounding this hole remains a topic of speculation, as is the full extent of the underlying cavern. Holes such as this are of particular interest because their interior caves are relatively protected from the harsh surface of Mars, making them relatively good candidates to contain Martian life. These pits are therefore prime targets for possible future spacecraft, robots, and even human interplanetary explorers.

Moon, Venus and Planet Earth

Composite Image Credit & Copyright: Fefo Bouvier

Explanation: In this engaging scene from planet Earth, the Moon shines through cloudy skies following sunset on the evening of September 8. Despite the fading light, the camera's long exposure still recorded a colorful, detailed view of a shoreline and western horizon looking toward the island San Gabriel from Colonia del Sacramento, Uruguay. Lights from Buenos Aires, Argentina are along the horizon on the left, across the broad Rio de la Plata estuary. The long exposure strongly overexposed the Moon and sky around it, though. So the photographer quickly snapped a shorter one to merge with the first image in the area around the bright lunar disk. As the the second image was made with a telephoto setting, the digital merger captures both Earth and sky, exaggerating the young Moon's slender crescent shape in relation to the two nearby bright stars. The more distant is bluish Spica, alpha star of the constellation Virgo. Closest to the Moon is Earth's evening star, planet Venus, emerging from a lunar occultation.

Loops of Gas and Dust Rise from Planetary Disks

Magnetic loops carry gas and dust above disks of planet-forming material circling stars, as shown in this artist's conception. These loops give off extra heat, which NASA's Spitzer Space Telescope detects as infrared light. The colors in this illustration show what an alien observer with eyes sensitive to both visible light and infrared wavelengths might see.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA

NGC 1333 Stardust

Image Credit & Copyright: Al Howard

Explanation: NGC 1333 is seen in visible light as a reflection nebula, dominated by bluish hues characteristic of starlight reflected by dust. A mere 1,000 light-years distant toward the heroic constellation Perseus, it lies at the edge of a large, star-forming molecular cloud. This striking close-up view spans about two full moons on the sky or just over 15 light-years at the estimated distance of NGC 1333. It shows details of the dusty region along with hints of contrasting red emission from Herbig-Haro objects, jets and shocked glowing gas emanating from recently formed stars. In fact, NGC 1333 contains hundreds of stars less than a million years old, most still hidden from optical telescopes by the pervasive stardust. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago.

Globules in the Running Chicken Nebula

Image Credit & Copyright: Fred Vanderhaven

Explanation: The eggs from this chicken may form into stars. The above pictured emission nebula, cataloged as IC 2944, is called the Running Chicken Nebula for the shape of its greater appearance. The image was taken recently from Siding Spring Observatory in Australia and presented in scientifically assigned colors. Seen near the center of the image are small, dark molecular clouds rich in obscuring cosmic dust. Called Thackeray's Globules for their discoverer, these "eggs" are potential sites for the gravitational condensation of new stars, although their fates are uncertain as they are also being rapidly eroded away by the intense radiation from nearby young stars. Together with patchy glowing gas and complex regions of reflecting dust, these massive and energetic stars form the open cluster Collinder 249. This gorgeous skyscape spans about 70 light-years at the nebula's estimated 6,000 light-year distance.

Sun and Prominence

Image Credit & Copyright: jp-Brahic

Explanation: Dramatic prominences can sometimes be seen looming just beyond the edge of the sun. Such was the case last week as a large prominence, visible above, highlighted a highly active recent Sun. A waving sea of hot gas is visible in the foreground chromosphere in great detail as it was imaged in one specific color of light emitted by hydrogen. A solar prominence is a cloud of solar gas held just above the surface by the Sun's magnetic field. The Earth, illustrated in the inset, is smaller than the prominence. Although very hot, prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the photosphere below them. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System, some of which may strike the Earth and trigger auroras.

Martian Sunset

Image Credit: Mars Exploration Rover Mission, Texas A&M, Cornell, JPL, NASA

Explanation: What would it be like to see a sunset on Mars? To help find out, the robotic rover Spirit was deployed in 2005 to park and watch the Sun dip serenely below the distant lip of Gusev crater. Colors in the above image have been slightly exaggerated but would likely be apparent to a human explorer's eye. Fine martian dust particles suspended in the thin atmosphere lend the sky a reddish color, but the dust also scatters blue light in the forward direction, creating a bluish sky glow near the setting Sun. Because Mars is farther away, the Sun is less bright and only about two thirds the diameter it appears from Earth. Images like this help atmospheric scientists understand not only the atmosphere of Mars, but atmospheres across the Solar System, including our home Earth.

NGC 7331 and Beyond

Image Credit & Copyright: Dietmar Hager, Torsten Grossmann

Explanation: Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, long telescopic exposures often result in an image that evokes a strong sense of depth. The effect is further enhanced in this sharp image by galaxies that lie beyond the gorgeous island universe. The background galaxies are about one tenth the apparent size of NGC 7331 and so lie roughly ten times farther away. Their close alignment on the sky with NGC 7331 occurs just by chance. Seen here through faint foreground dust clouds lingering above the plane of Milky Way, this visual grouping of galaxies is also known as the Deer Lick Group.

Möbius Arch Moonrise

Image Credit & Copyright: Laurie Hatch

Explanation: Only two days past full, February's moon shines through thin clouds, rising on the left in this fisheye night skyscape. The moonlight illuminates a weathered, rounded foreground in the Alabama Hills, conveniently located east of Mt. Whitney along the Sierra Nevada range in California, USA, planet Earth. Orion the Hunter stands at the right, a familiar northern winter constellation. Bright Jupiter, the solar system's ruling gas giant, is near center at the top of the frame. Below Jupiter, Sirius, alpha star of the Big Dog, poses above a bowed and twisted landform known as Möbius Arch, its curve reminiscent of the mathematically famous surface with only one side. Of course, instead of using rock, wind, and weather, a Möbius strip is easier to make with paper, scissors, and tape.

Asteroid Tracks Among the Stars

More than 100 asteroids were captured in this view from NASA's Wide-field Infrared Survey Explorer, or WISE, during its primary all-sky survey. In August of this year, the mission was revived to hunt more asteroids, and renamed NEOWISE.

Not all of the asteroids are easy to see, but some stand out as a series of dots. Each dot in a track shows one asteroid, captured at different times as it marched across the sky. The asteroid at center left is called (2415) Ganesa.

Clusters of stars can also be seen; for example, NGC 2158 glitters like a jeweled brooch at center right. There are about 2,500 stars in this view, which is about 30 light-years across.

Clouds of gas and dust surround the region, visible only in infrared light.

These data were acquired in March 2010, before WISE was put into hibernation in 2011.

JPL manages NEOWISE for NASA's Science Mission Directorate at the agency's headquarters in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.