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Please vote for the TWO best Astronomy Pictures of the Day (image and text) of November 13-19, 2011.
(Repeated APODs are not included in the poll.)
All titles are clickable and link to the original APOD page.
We ask for your help in choosing an APOW as this helps Jerry and Robert create "year in APOD images" review lectures, create APOM and APOY polls that can be used to create a free PDF calendar at year's end, and provides feedback on which images and APODs were relatively well received. You can select two top images for the week.
We are very interested in why you selected the APODs you voted for, and enthusiastically welcome your telling us why by responding to this thread.
Thank you!
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The longer you look at this image, the more you see. Perhaps your eye is first drawn to the picturesque waterfall called Skogarfoss visible on the image right. Just as prevalent, however, in this Icelandic visual extravaganza, is the colorful arc of light on the left. This chromatic bow is not a rainbow, since the water drops did not originate in rainfall nor are they reflecting light from the Sun. Rather, the drops have drifted off from the waterfall and are now illuminated by the nearly full Moon. High above are the faint green streaks of aurora. The scene, captured one night last month, also shows a beautiful starscape far in the background, including the Big Dipper, part of the constellation of the Great Bear (Ursa Major).
Our Sun is becoming a busy place. Taken just last week, the Sun was captured sporting numerous interesting features including one of the larger sunspot groups yet recorded: AR 1339 visible on the image right. Only last year, the Sun was emerging from an unusually quiet Solar Minimum that lasted for years. The above image was recorded in a single color of light called Hydrogen Alpha, inverted, and false colored. Spicules cover much of the Sun's face. The gradual brightening towards the Sun's edges is caused by increased absorption of relatively cool solar gas and called limb darkening. Just over the Sun's edges, several scintillating prominences protrude, while prominences on the Sun's face are seen as light streaks. Possibly the most visually interesting of all are the magnetically tangled active regions containing cool sunspots. As our Sun's magnetic field winds toward Solar Maximum over the next few years, increased activity will likely create times when the Sun's face is even more complex.
Hot, young stars and cosmic pillars of gas and dust seem to crowd into 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 dark shapes are highlighted in this colorful skyscape. The image includes data from narrowband filters, mapping emission from atomic oxygen, hydrogen, and sulfur into blue, green, and red hues. The atomic emission is powered by 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 40 light-years at the estimated distance of NGC 7822.
This cosmic vista stretches almost 20 degrees across the gentle constellation Taurus. It begins at the Pleiades and ends at the Hyades, two of the best known star clusters in planet Earth's sky. At left, the lovely Pleiades star cluster is about 400 light-years away. In a familiar celestial scene, the cluster stars shine through dusty clouds that scatter blue starlight. At right, the V-shaped Hyades cluster looks more spread out compared to the compact Pleiades and lies much closer, 150 light-years distant. Of course, the Hyades cluster stars seem anchored by bright Aldebaran, a red giant star with a yellowish appearance. But Aldebaran actually lies only 65 light-years away, by chance along the line of sight to the Hyades cluster. Faint dust clouds found near the edge of the Taurus Molecular Cloud are also evident throughout the remarkable 12 panel mosaic. The wide field of view includes the youthful star T Tauri and Hind's variable nebula about four degrees left of Aldebaran on the sky.
This colorful topographical map of the Moon is centered on the lunar farside, the side not seen from planet Earth. That view is available to the Lunar Reconnaissance Orbiter though, as the spacecraft's wide angle camera images almost the entire lunar surface every month. Stereo overlap of the imaging has allowed the computation of topographical maps with coverage between 80 degrees north and south latitude. The results have about a 300 meter resolution on the lunar surface and 10 to 20 meter elevation accuracy. Data closer to the north and south poles is filled in using the orbiter's laser altimeter. In this map, white, red, green, and purple represent progressively lower elevations. In fact, the large circular splotch tending to purple hues at the bottom is the farside's South Pole-Aitken Basin. About 2500 kilometers in diameter and over 12 kilometers deep, it is one of the largest impact basins in the Solar System.
The mysterious blue reflection nebula found in catalogs as VdB 152 or Ced 201 really is very faint. It lies at the tip of the long dark nebula Barnard 175 in a dusty complex that has also been called Wolf's Cave. The cosmic apparitions are nearly 1,400 light-years away along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving the the nebula its characteristic blue color. Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity. This deep telescopic image of the region spans about 7 light-years.
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Poll: Astronomy Picture of the Week for 2011 November 13-19
Poll: Astronomy Picture of the Week for 2011 November 13-19
A closed mouth gathers no foot.