Astronomy Picture

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 20

Eclipse City
Credit & Copyright: Alfred Lee Explanation: During July 22nd's solar eclipse, the Moon's dark shadow traced a narrow path as it raced eastward across India and China and on into the Pacific. Hong Kong was south of the shadow's path, so a total eclipse was not visible there, but a partial eclipse was still enjoyed by inhabitants of the populous city. And while many were (safely!) watching the sky, images of the partially eclipsed Sun adorned the city itself. In this downlooking photo, taken at 9:40am local time, a remarkable array of solar eclipse views was created by reflection in a grid of eastward facing skyscraper windows. The photographer's location was the 27th floor of Two Pacific Place.


Tomorrow's picture: looking up

I have passed this building on Hong Kong Side many times riding on the electric tramway which runs down the main road.. (old Uk trams are still used there) - Tony

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 21

The Whale and the Hockey Stick
Credit & Copyright: Josef Poepsel, Stefan Binnewies (Capella Observatory) Explanation: NGC 4631 is a big beautiful spiral galaxy seen edge-on (top right) only 25 million light-years away towards the small northern constellation Canes Venatici. This galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others the popular moniker of The Whale Galaxy. Either way, it is similar in size to our own Milky Way. In this gorgeous color image, the Whale's dark interstellar dust clouds, yellowish core, and young blue star clusters are easy to spot. A companion galaxy, the small elliptical NGC 4627, appears above the Whale Galaxy. At the lower left is another distorted galaxy, the hockey stick-shaped NGC 4656. The distortions and mingling trails of gas detected at other wavelengths suggest that all three galaxies have had close encounters with each other in their past. The Whale Galaxy is also known to have spouted a halo of hot gas glowing in x-rays.


Tomorrow's picture: light-weekend

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 22

The Gum Nebula
Credit & Copyright: Axel Mellinger Explanation: Named for Australian astronomer Colin Stanley Gum (1924-1960), The Gum Nebula is so large and close it is actually hard to see. In fact, we are only about 450 light-years from the front edge and 1,500 light-years from the back edge of this cosmic cloud of glowing hydrogen gas. Covered in this 41 degree-wide mosaic of H-alpha images, the faint emission region is otherwise easy to lose against the background of Milky Way stars. The complex nebula is thought to be a supernova remnant over a million years old, sprawling across the southern constellations Vela and Puppis. Sliding your cursor over this spectacular wide field view will reveal the location of objects embedded in The Gum Nebula, including the Vela supernova remnant.


Tomorrow's picture: big break

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 23

Giant Cluster Bends, Breaks Images
Credit: NASA, ESA, H. Lee & H. Ford (Johns Hopkins U.) Explanation: What are those strange blue objects? Many of the brightest blue images are of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here typically appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens. A gravitational lens can create several images of background galaxies, analogous to the many points of light one would see while looking through a wine glass at a distant street light. The distinctive shape of this background galaxy -- which is probably just forming -- has allowed astronomers to deduce that it has separate images at 4, 10, 11, and 12 o'clock, from the center of the cluster. A blue smudge near the cluster center is likely another image of the same background galaxy. In all, a recent analysis postulated that at least 33 images of 11 separate background galaxies are discernable. This spectacular photo of galaxy cluster CL0024+1654 from the Hubble Space Telescope was taken in November 2004.



Tomorrow's picture: long clouds

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 24

Morning Glory Clouds Over Australia
Credit & Licence: Mick Petroff; Tip Thanks: James Holmes (Cairns) Explanation: 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. Pictured above, photographer Mick Petroff photographed some Morning Glory clouds from his airplane near the Gulf of Carpentaria, Australia.



Tomorrow's picture: equinox at saturn

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 25

Equinox at Saturn
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA Explanation: What would Saturn's rings look like if the ring plane pointed directly at the Sun? That situation occurred earlier this month when equinox occurred on Saturn. Since the Earth is nearly in the same direction as the Sun from Saturn, the rings appeared to disappear from Earth. From the robotic Cassini spacecraft orbiting Saturn, however, the unusually illuminated ring plane could be viewed from on high. Pictured above, Saturn's rings, darker than ever seen before, were captured just a few hours before equinox on 2009 August 10. The reason for the unusual brightness of an inner ring is currently unknown, but possibly related to particle sizes there being larger than the 10 meter average thickness of the rest of Saturn's rings. Short light streaks in the frame are artificial image artifacts and have nothing to do with Saturn's ring plane. Planetary scientists will be studying ring images taken near equinox to help better understand the dynamics and particle size distribution of the Solar System's most extensive ring system.



Tomorrow's picture: the classics

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 26

Classic Orion Nebulae
Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography) Explanation: The Great Nebula in Orion, also known as M42, is one of the most famous nebulae in the sky. The star forming region's glowing gas clouds and hot young stars are near the center of this colorful deep sky image that includes the smaller nebula M43 and dusty, bluish reflection nebulae NGC 1977 and friends on the left. Located at the edge of an otherwise invisible giant molecular cloud complex, these eye-catching nebulae represent only a small fraction of this galactic neighborhood's wealth of interstellar material. Captured with very modest equipment, the gorgeous skyscape was awarded Best in Show at the 2009 Starfest International Salon of Astrophotography. Judges commented that the detail and shading were exquisite in this version of a classic astronomical image. The field spans nearly 3 degrees or about 75 light-years at the Orion Nebula's estimated distance of 1,500 light-years.


Tomorrow's picture: dark sky

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 27

A Dark Sky Over Sequoia National Park
Credit: D. Duriscoe, C. Duriscoe, R. Pilewski, & L. Pilewski, U.S. NPS Night Sky Program Explanation: Scroll right to take in the view from the highest summit in the contiguous USA. The above 360-degree digitally stitched panorama, taken in mid-July, shows the view from 4,400-meter high Mt. Whitney in Sequoia National Park, California. In the foreground, angular boulders populate Mt. Whitney's summit while in the distance, just below the horizon, peaks from the Sierra Nevada mountain range are visible. Sky sights include light pollution emanating from Los Angeles and Fresno, visible just above the horizon. Dark clouds, particularly evident on the image left well above the horizon, are the remnants of a recent thunderstorm near Death Valley. High above, the band of the Milky Way Galaxy arches across the image left. Bright airglow bands are visible all over the sky but are particularly prominent on the image right. The planet Jupiter appears as the brightest point on the image left. A discerning eye can also find a faint image of the far distant Andromeda galaxy, a satellite trail, and many constellations. Today marks the 100th anniversary of the completion of the historic stone shelter on Mt. Whitney, visible toward the image right.



Tomorrow's picture: colorful sky

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 28

NGC 7822 in Cepheus
Credit & Copyright: Don Goldman Explanation: Pillars of gas, dust, and young, hot stars fill the center of NGC 7822. At the edge of a giant molecular cloud toward the northern constellation Cepheus, the glowing star forming region lies about 3,000 light-years away. Within the nebula, bright edges and tantalizing shapes are highlighted in this colorful skyscape. The image includes data from both broadband and narrowband filters, mapping emission from atomic oxygen, hydrogen, and sulfur into blue, green, and red hues. The atomic emission is powered by the energetic radiation from the hot stars, whose powerful winds and radiation also sculpt and erode the denser pillar shapes. Stars could still be forming inside the pillars by gravitational collapse, but as the pillars are eroded away, any forming stars will ultimately be cutoff from their reservoir of star stuff. This field spans around 30 light-years at the estimated distance of NGC 7822.


Tomorrow's picture: light-weekend

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 August 29

NGC 7771 Galaxy Group
Credit & Copyright: Kent Biggs Explanation: Slide your cursor over the image to identify three members of this intriguing gathering of galaxies. Known as the NGC 7771 Group, they lie almost 200 million light-years away toward the high flying constellation Pegasus. The largest galaxy, barred spiral NGC 7771, is itself about 75,000 light-years across, but will someday find itself part of a larger galaxy still. As the galaxies of the group make repeated close passages, they will finally merge into one very large galaxy. Played out over hundreds of millions of years, the process is understood to be a normal part of the evolution of galaxies, including our own Milky Way.
Editor's Note: The labeled version of the image was generated by Astrometry.net.

Tomorrow's picture: small astronauts