Astronomy Picture of the Day

Astronomy Picture of the Day

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.

2012 January 31
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The Helix Nebula from the VISTA Telescope
Credit: ESO/VISTA/J. Emerson; Acknowledgment: Cambridge Astronomical Survey Unit  

 

 

Explanation: Will our Sun look like this one day? The Helix Nebula is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space appear from our vantage point as if we are looking down a helix. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The Helix Nebula, given a technical designation of NGC 7293, lies about 700 light-years away towards the constellation of the Water Bearer (Aquarius) and spans about 2.5 light-years. The above picture was taken three colors on infrared light by the 4.1-meter Visible and Infrared Survey Telescope for Astronomy (VISTA) at the European Southern Observatory’s Paranal Observatory in Chile. A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.

Astronomy Picture of the Day for Jan. 29th

Astronomy Picture of the Day

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.

2012 January 29
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Molecular Cloud Barnard 68
Image Credit: FORS Team, 8.2-meter VLT Antu, ESO 

 

Explanation: Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud. Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars. The eerily dark surroundings help make the interiors of molecular clouds some of the coldest and most isolated places in the universe. One of the most notable of these dark absorption nebulae is a cloud toward the constellation Ophiuchus known as Barnard 68, pictured above. That no stars are visible in the center indicates that Barnard 68 is relatively nearby, with measurements placing it about 500 light-years away and half a light-year across. It is not known exactly how molecular clouds like Barnard 68 form, but it is known that these clouds are themselves likely places for new stars to form. In fact, Barnard 68 itself has been found likely to collapse and form a new star system. It is possible to look right through the cloud in infrared light.

Astronomy Picture of the Day for Jan. 28th

Astronomy Picture of the Day

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.

2012 January 28
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Planet Aurora Borealis
Image Credit & Copyright: Göran Strand 

Explanation: Illuminated by an eerie greenish light, this remarkable little planet is covered with ice and snow and ringed by tall pine trees. Of course, this little planet is actually planet Earth, and the surrounding stars are above the horizon near Östersund, Sweden. The pale greenish illumination is from a curtain of shimmering Aurora Borealis also known as the Northern Lights. The display was triggered when a giant solar coronal mass ejection (CME) rocked planet Earth’s magnetosphere on January 24th and produced a strong geomagnetic storm. Northern hemisphere skygazers will also recognize the familiar orientation of stars at the left, including the Pleiades and Hyades star clusters and the stars of Orion. Increasing solar activity has caused recent auroral displays to be wide spread, including Aurora Australis, the Southern Lights, at high southern latitudes.

Astronomy Picture of the Day for Jan. 27th

Astronomy Picture of the Day

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.

2012 January 27
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NGC 3239 and SN 2012A
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, University of Arizona 

 

Explanation: About 40,000 light-years across, pretty, irregular galaxy NGC 3239 lies near the center of this lovely field of galaxies in the galaxy rich constellation Leo. At a distance of only 25 million light-years it dominates the frame, sporting a peculiar arrangement of structures, young blue star clusters and star forming regions, suggesting that NGC 3239 (aka Arp 263) is the result of a galaxy merger. Appearing nearly on top of the pretty galaxy is a bright, spiky, foreground star, a nearby member of our own Milky Way galaxy almost directly along our line-of-sight to NGC 3239. Still, NGC 3239 is notable for hosting this year’s first confirmed supernova, designated SN 2012A. It was discovered early this month by supernova hunters Bob Moore, Jack Newton, and Tim Puckett. Indicated in a cropped version of the wider image, SN 2012A is just below and right of the bright foreground star. Of course, based on the light-travel time to NGC 3239, the supernova explosion itself occurred 25 million years ago, triggered by the core collapse of a massive star.

Astronomy Picture of the Day for Jan. 23

Astronomy Picture of the Day

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.

2012 January 23
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Deep Orion Over the Canary Islands
Image Credit & Copyright: Juan Carlos Casado (TWAN) 

Explanation: Which attracts your eye more — the sky or the ground? On the ground are rocky peaks in Teide National Park on Tenerife Island of the Spanish Canary Islands off the northwestern coast of Africa. The volcanic landscape features old island summits and is sometimes used as a testbed for instruments on future Martian rovers. The lights of a nearby hotel shine on the far left. Storm clouds are visible on the horizon, artificially strutted from multiple exposures. Dividing the sky, across the middle of the above deep image, is the vertical band of the Milky Way Galaxy. The red circle on the right is Barnard’s Loop, near the center of which are the famous belt stars of the constellation Orion. Soon after the above image was taken, during an evening earlier this year, storm clouds rolled across, and indoor locations began to attract eyes the most.

Astronomy Picture of the Day for Jan. 15th

Astronomy Picture of the Day

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.

2012 January 15
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Infrared Portrait of the Large Magellanic Cloud
Credit: ESA / NASA / JPL-Caltech / STScI 

Explanation: Cosmic dust clouds ripple across this infrared portrait of our Milky Way’s satellite galaxy, the Large Magellanic Cloud. In fact, the remarkable composite image from the Herschel Space Observatory and the Spitzer Space Telescope show that dust clouds fill this neighboring dwarf galaxy, much like dust along the plane of the Milky Way itself. The dust temperatures tend to trace star forming activity. Spitzer data in blue hues indicate warm dust heated by young stars. Herschel’s instruments contributed the image data shown in red and green, revealing dust emission from cooler and intermediate regions where star formation is just beginning or has stopped. Dominated by dust emission, the Large Magellanic Cloud’s infrared appearance is different from views in optical images. But this galaxy’s well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center. A mere 160,000 light-years distant, the Large Cloud of Magellan is about 30,000 light-years across.

Astronomy Picture of the Day for August 10th

Astronomy Picture of the Day

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.

The Summer Triangle Over Catalonia

Image Credit: Copyright: Juan Carlos Casado (TWAN)Explanation: Can you find the Summer Triangle? It’s not hard to find this famous triangle of stars this time of year from northern locations. Just look straight up after sunset and find three of the brightest stars in the sky that nearly form a triangle. Then compare these stars to sky images like the one shown above, or hold up a smart phone running a good sky labelling application. The three stars that form the vertexes of the Summer Triangle are Vega, Deneb, and Altair. Pictured above is a 360 degree full sky projection framing not only the Summer Triangle but the great arch of our Milky Way Galaxy. The image was taken last week in front of a small river that encircles the historic town of Sant Llorenç de la Muga in Catalonia, northeastern Spain.