Morning Glory Clouds over Australia

What causes these long, strange clouds? No one is sure. A rare type of cloud known as a Morning Glory cloud can stretch 1,000 kilometers long and occur at altitudes up to two kilometers high. Although similar roll clouds have been seen at specific places across the world, the ones over Burketown, Queensland Australia occur predictably every spring. Long, horizontal, circulating tubes of air might form when flowing, moist, cooling air encounters an inversion layer, an atmospheric layer where air temperature atypically increases with height. These tubes and surrounding air could cause dangerous turbulence for airplanes when clear. Morning Glory clouds can reportedly achieve an airspeed of 60 kilometers per hour over a surface with little discernible wind. On this picture, photographer Mick Petroff photographed some Morning Glory clouds from his airplane near the Gulf of Carpentaria, Australia.

Image Credit & Licence: Mick Petroff; James Holmes
Explanation from: http://apod.nasa.gov/apod/ap090824.html

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The Milky Road

Inspired during a visit to Fort Davis, Texas, home of McDonald Observatory and dark night skies, photographer Larry Landolfi created this tantalizing fantasy view. The composited image suggests the Milky Way is a heavenly extension of a deserted country road. Of course, the name for our galaxy, the Milky Way (in Latin, Via Lactea), does refer to its appearance as a milky band or path in the sky. In fact, the word galaxy itself derives from the Greek for milk. Visible on moonless nights from dark sky areas, though not so colorful as in this image, the glowing celestial band is due to the collective light of myriad stars along the plane of our galaxy, too faint to be distinguished individually. The diffuse starlight is cut by dark swaths of obscuring galactic dust clouds. At the beginning of the 17th century, Galileo turned his telescope on the Milky Way and announced it to be composed of innumerable stars.

Image Credit & Copyright: Larry Landolfi
Explanation from: http://apod.nasa.gov/apod/ap071020.html

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Sunset on Mars: A Moment Frozen in Time

On May 19th, 2005, NASA’s Mars Exploration Rover Spirit captured this stunning view of the Sun sinking below the rim of Gusev crater on Mars. This Panoramic Camera (Pancam) mosaic was taken around 6:07 in the evening of the rover’s 489th Martian day, or sol. Spirit was commanded to stay awake briefly after sending that sol’s data to the Mars Odyssey orbiter just before sunset. This small panorama of the western sky was obtained using Pancam’s 750-nanometer, 530-nanometer and 430-nanometer color filters. This filter combination generates false-color images that are similar to what a human would see, but with the colors slightly exaggerated.

In this image, the bluish glow in the sky above the Sun would be visible to us if we were there, but an artifact of the Pancam’s infrared imaging capabilities is that with this filter combination, the redness of the sky farther from the sunset is exaggerated compared to the daytime colors of the Martian sky.

Because Mars is farther from the Sun than the Earth is, the Sun appears only about two-thirds the size that it appears in a sunset seen from the Earth. The terrain in the foreground is the rock outcrop “Jibsheet”, a feature that Spirit has been investigating for several weeks. The floor of Gusev crater is visible in the distance, and the Sun is setting behind the wall of Gusev some 80 kilometers (50 miles) in the distance.

This mosaic is yet another example from the rover of a beautiful Martian scene that also captures some important scientific information. Specifically, sunset and twilight images are occasionally acquired by the science team to determine how high into the atmosphere the Martian dust extends, and to look for dust or ice clouds. Other images have shown that the twilight glow remains visible, but increasingly fainter, for up to two hours before sunrise or after sunset. The long Martian twilight (compared to Earth’s) is caused by sunlight scattered around to the night side of the planet by abundant high altitude dust. Similar long twilights or extra-colorful sunrises and sunsets sometimes occur on Earth when tiny dust grains from powerful volcanic eruptions scatter light high in the atmosphere.

Image Credit: NASA/JPL/Texas A&M/Cornell
Explanation from: http://earthobservatory.nasa.gov/IOTD/view.php?id=5582

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Meteor and Moonbow over Wallaman Falls

Which feature takes your breath away first in this encompassing panorama of land and sky? The competition is strong with a waterfall, meteor, starfield, and even a moonbow all vying for attention. It is interesting to first note, though, what can't be seen -- a rising moon on the other side of the camera. The bright moon not only illuminated this beautiful landscape in Queensland, Australia in June 2011, but also created the beautiful moonbow seen in front of Wallaman Falls. Just above the ridge in this image is the horizontal streak of an airplane. Toward the top of the frame is the downward streak of a bright meteor, a small pebble from across our Solar System that lit up as it entered the Earth's atmosphere. Well behind the meteor are numerous bright stars and nebula seen toward the center of our Galaxy. Finally, far in the background, is the band of our Milky Way Galaxy, running diagonally from the lower left to the upper right in the image but also circling the entire sky.

Image Credit & Copyright: Thierry Legault
Explanation from: http://apod.nasa.gov/apod/ap121112.html

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Hunter's Moon over the Alps

A Full Moonset can be a dramatic celestial sight, and Full Moons can have many names. Late October's 2012 Full Moon, the second Full Moon after the northern hemisphere autumnal equinox, has been traditionally called the Hunter's Moon. According to lore, the name is a fitting one because this Full Moon lights the night during a time for hunting in preparation for the coming winter months. In this scene, Hunter's Moon shines with a rich yellow light, setting as dawn comes to the Italian Alps. Topping out at over 11,000 feet, the snowy peak known as Rochemelon glows, just catching the first reddened light of the rising Sun.

Image Credit & Copyright: Stefano De Rosa
Explanation from: http://apod.nasa.gov/apod/ap121103.html

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Moon Shadow Sequence

On the morning of November 14, 2012 the Moon's umbral shadow tracked across northern Australia before heading into the southern Pacific. Captured from a hilltop some 30 miles west of the outback town of Mount Carbine, Queensland, a series of exposures follows the progress of the total solar eclipse in this dramatic composite image. The sequence begins near the horizon. The Moon steadily encroaches on the reddened face of the Sun, rising as the eclipse progresses. At the total phase, lasting about 2 minutes for that location, an otherwise faint solar corona shimmers around the eclipsed disk. Recorded during totality, the background exposure shows a still sunlit sky near the horizon, just beyond a sky darkened by the shadow of the Moon.

Image Credit & Copyright: Ben Cooper
Explanation from: http://apod.nasa.gov/apod/ap121116.html

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Sheldon Glacier

View of Sheldon Glacier with Mount Barre in the background, seen from Ryder Bay near Rothera Research Station, Adelaide Island, Antarctica. A new NASA/British Antarctic Survey study examines why Antarctic sea ice cover has increased under the effects of climate change over the past two decades.

Image Credit: British Antarctic Survey
Explanation from: http://www.nasa.gov/topics/earth/features/antarctica20121112.html

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Hubble Captures View of 'Mystic Mountain'

This craggy fantasy mountaintop enshrouded by wispy clouds looks like a bizarre landscape from Tolkien's "The Lord of the Rings" or a Dr. Seuss book, depending on your imagination. The NASA Hubble Space Telescope image, which is even more dramatic than fiction, captures the chaotic activity atop a three-light-year-tall pillar of gas and dust that is being eaten away by the brilliant light from nearby bright stars. The pillar is also being assaulted from within, as infant stars buried inside it fire off jets of gas that can be seen streaming from towering peaks.

This turbulent cosmic pinnacle lies within a tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away in the southern constellation Carina.

Scorching radiation and fast winds (streams of charged particles) from super-hot newborn stars in the nebula are shaping and compressing the pillar, causing new stars to form within it. Streamers of hot ionized gas can be seen flowing off the ridges of the structure, and wispy veils of gas and dust, illuminated by starlight, float around its towering peaks. The denser parts of the pillar are resisting being eroded by radiation much like a towering butte in Utah's Monument Valley withstands erosion by water and wind.

Nestled inside this dense mountain are fledgling stars. Long streamers of gas can be seen shooting in opposite directions off the pedestal at the top of the image. Another pair of jets is visible at another peak near the center of the image. These jets (known as HH 901 and HH 902, respectively) are the signpost for new star birth. The jets are launched by swirling disks around the young stars, which allow material to slowly accrete onto the stars' surfaces.

Hubble's Wide Field Camera 3 observed the pillar on February 1-2, 2010. The colors in this composite image correspond to the glow of oxygen (blue), hydrogen and nitrogen (green), and sulfur (red).

Image Credit: NASA, ESA, and M. Livio, STScI
Explanation from: http://hubblesite.org/newscenter/archive/releases/2010/13/image/a/

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Panoramic view From 'Rocknest' Position of Curiosity Mars Rover

This panorama is a mosaic of images taken by the Mast Camera (Mastcam) on the NASA Mars rover Curiosity while the rover was working at a site called "Rocknest" in October and November 2012. 

The center of the scene, looking eastward from Rocknest, includes the Point Lake area. After the component images for this scene were taken, Curiosity drove 83 feet (25.3 meters) on Nov. 18 from Rocknest to Point Lake. From Point Lake, the Mastcam is taking images for another detailed panoramic view of the area further east to help researchers identify candidate targets for the rover's first drilling into a rock. 

The image has been white-balanced to show what the rocks and soils in it would look like if they were on Earth.

Image Credit: NASA/JPL-Caltech/Malin Space Science Systems
Explanation from: http://www.nasa.gov/mission_pages/msl/multimedia/pia16453.html

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Iridescent Clouds from the Top of the World Highway

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. Therefore, different colors will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too far from the Sun to exhibit striking colors. This iridescent cloud was photographed in 2010 from the Top of the World Highway outside Dawson City, in the Yukon Territory in Northern Canada.

Image Credit & Copyright: Charles Stankievech & Sophie Springer
Explanation from: http://apod.nasa.gov/apod/ap110208.html

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Andromeda in the Infrared

NASA's Spitzer Space Telescope has captured stunning infrared views of the famous Andromeda galaxy to reveal insights that were only hinted at in visible light.

This Spitzer's 24-micron mosaic is the sharpest image ever taken of the dust in another spiral galaxy. This is possible because Andromeda is a close neighbor to the Milky Way at a mere 2.5 million light-years away.

The Spitzer multiband imaging photometer's 24-micron detector recorded 11,000 separate snapshots to create this new comprehensive picture. Asymmetrical features are seen in the prominent ring of star formation. The ring appears to be split into two pieces, forming the hole to the lower right. These features may have been caused by interactions with satellite galaxies around Andromeda as they plunge through its disk.

Spitzer also reveals delicate tracings of spiral arms within this ring that reach into the very center of the galaxy. One sees a scattering of stars within Andromeda, but only select stars that are wrapped in envelopes of dust light up at infrared wavelengths.

This is a dramatic contrast to the traditional view at visible wavelengths, which shows the starlight instead of the dust. The center of the galaxy in this view is dominated by a large bulge that overwhelms the inner spirals seen in dust. The dust lanes are faintly visible in places, but only where they can be seen in silhouette against background stars.

The data were taken on August 25, 2004, the one-year anniversary of the launch of the space telescope. The observations have been transformed into this remarkable gift from Spitzer - the most detailed infrared image of the spectacular galaxy to date.

Image Credit: NASA/JPL-Caltech/K. Gordon (University of Arizona)
Explanation from: http://www.spitzer.caltech.edu/images/1493-ssc2005-20a1-Andromeda-in-the-Infrared

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