A different astronomy and space science related image is featured each day, along with a brief explanation.
http://antwrp.gsfc.nasa.gov/apod/astropix.html - 07/06/15 07:45:12 - 11/28/04 12:29:17
Colorful Clouds Near Rho Ophiuchi Image Credit & Copyright: Markus NollerDeep-Sky-Images
Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear darkAntares, a red supergiant and one of the brighter stars in the night sky, lights up the yellow-red clouds on the lower center of the featured imageRho Ophiuchi lies at the center of the blue nebula on the left. The distant globular clusterM4 is visible to the upper right of center. These star clouds are even more colorful than humans can see, emitting light across the electromagnetic spectrum.
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Zeta Oph: Runaway Star Image Credit: , JPL-Caltech, Spitzer Space Telescope
Like a ship plowing through cosmic seas, Zeta Ophiuchi produces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait. In the false-color view, bluish Zeta Oph, a star about 20 times more massive than the Sun, lies near the center of the frame, moving toward the left at 24 kilometers per second. Its strong stellar wind precedes it, compressing and heating the dusty interstellar material and shaping the curved shock front. Around it are clouds of relatively undisturbed material. What set this star in motion? Zeta Oph was likely once a member of a binary star system, its companion star was more massive and hence shorter lived. When the companion exploded as a supernova catastrophically losing mass, Zeta Oph was flung out of the system. About 460 light-years away, Zeta Oph is 65,000 times more luminous than the Sun and would be one of the brighter stars in the sky if it weren't surrounded by obscuring dust. The image spans about 1.5 degrees or 12 light-years at the estimated distance of Zeta Ophiuchi
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Aurora Australis Robert Schwarz (South Pole Station)
Not fireworks, these intense shimmering lights still danced across Earth's night skies late last month, seen here above the planet's geographic south pole. The stunning auroral displays were triggered as a coronal mass ejection blasted from the Sun days earlier impacted the magnetosphere, beginning a widespread geomagnetic storm. The six fisheye panels were recorded with digital camera and battery in a heated box to guard against -90 degree F ambient temperatures of the long winter night. Around the horizon are south pole astronomical observatories, while beyond the Aurora Australis stretch the stars of the southern Milky Way.
Venus and Jupiter are Far Image Credit & Adam Tomaszewski
On June 30 Venus and Jupiter were actually far apart, but both appeared close in western skies at dusk. Near the culmination of this year's , the two bright evening planets are captured in the same telescopic field of view in this sharp digital stack of images taken after sunset from Poznań in west-central Poland. In fact, banded gas giant Jupiter was about 910 million kilometers from Poland. That's over 11 times farther than crescent Venus, only 78 million kilometers distant at the time. But since the diameter of giant planet Jupiter is over 11 times larger than Venus both planets show about the same angular size. Of course, 16th century Polish astronomer Nicolaus Copernicus would also have enjoyed the simultaneous telescopic view including Jupiter's four Galilean moons and a crescent Venus. Observations of Jupiter's moons and Venus' crescent phase were evidence for the Copernican or heliocentric model of the solar system.
Venus and Jupiter are Close Composite Image Credit & Copyright:Wang, Letian
On June 30, Venus and Jupiter were close in western skies at dusk. Near the culmination of this year's gorgeous conjunction, the two bright evening planets are captured in the same telescopic field of view in this image taken after sunset from Bejing, China. As the two bright planets set together in the west, a nearly Full Moon rose above the horizon to the south and east. Imaged that night with the same telescope and camera, the rising Moon from the opposite part of the sky is compared with the planetary conjunction for scale in the digitally composited image. The full lunar disk covers an angle of about 1/2 degree on the sky. Visible as well in binoculars and small telescopes are Venus' crescent and Jupiter's four Galilean moons. Of course, Venus and Jupiter are still close
pixels in space
Venus, Jupiter, and Noctilucent Clouds Image Credit & Copyright: Petr Horálek
Have you seen the passing planets yet? Today the planets Jupiter and Venus pass within half a degree of each other as seen from Earth. This conjunction, visible all over the world, is quite easy to see -- just look to the west shortly after sunset. The brightest objects visible above the horizon will be Venus and Jupiter, with Venus being the brighter of the two. Featured above, the closing planets were captured two nights ago in a sunset sky graced also by high-level noctilucent clouds. In the foreground, the astrophotographer's sister takes in the vista from a bank of the Sec Reservoir in the Czech Republic. She reported this as the first time she has seen noctilucent cloudsJupiter and Venus will appear even closer together tonight and will continue to be visible in the same part of the sky until mid-August.
Tonight: open space
An Unusual Mountain on Asteroid Ceres Image Credit: JPL-CaltechUCLA, MPS/DLR/IDA
What created this large mountain on asteroid Ceres? No one is yet sure. As if in anticipation of today being AsteroidDay on Earth, the robotic spacecraft Dawn in orbit around Ceres took the best yet image of an unusually tall mountain on the Asteroid Belt's largest asteroid. Visible at the top of the featured image, the exceptional mountain rises about five kilometers up from an area that otherwise appears pretty level. The image was taken about two weeks ago from about 4,400 kilometers away. Although origin hypotheses for the mountain include volcanism, impacts, and plate tectonics, clear evidence backing any of these is currently lacking. Also visible across Ceres' surface are some enigmatic light areas: bright spots whose origin and composition that also remain an active topic of investigation. Even though Dawn is expected to continue to orbit Ceres, officially dubbed a dwarf planet, for millions of years, the hydrazine fuel used to point Dawn's communications antenna toward Earth is expected to run out sometime next year.
Tonight & tomorrow: See Venus & Jupiter together after sunsetstar clouds
2015 June 29
Sunspot Group AR 2339 Crosses the Sun Images Credit: SDO; Video compilation & Copyright: Stanislav KorotkiyAstroAlert) & Mikhail Chubarets; Music: Pas de Deux (Bird Creek)
How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent a few weeks ago as the active region AR 2339 came around the limb of the Sun and was tracked for the next 12 days by NASA's Solar Dynamic Observatory. In the featured time lapse video, some sunspots drift apart, while others merge. All the while, the dark central umbral regions shift internally and their surrounding lighter penumbras shimmer and wave. The surrounding appears to flicker as the carpet of yellow granules come and go on the time scale of hours. In general, sunspots are relatively cool regions where the local magnetic field pokes through the Sun's surface and inhibits heating. Over the past week, an even more active region -- AR 2371 -- has been crossing the Sun and releasing powerful flares that have resulted in impressive auroras here on Earth.
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