Astronomy Picture of the Day

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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.
2008 August 24

Grand Spiral Galaxy NGC 1232
Credit: FORS1, 8.2-meter VLT Antu, ESO Explanation: Galaxies are fascinating not only for what is visible, but for what is invisible. Grand spiral galaxy NGC 1232, captured in detail by one of the new Very Large Telescopes, is a good example. The visible is dominated by millions of bright stars and dark dust, caught up in a gravitational swirl of spiral arms rotating about the center. Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them. Less visible, but detectable, are billions of dim normal stars and vast tracts of interstellar gas, together wielding such high mass that they dominate the dynamics of the inner galaxy. Invisible are even greater amounts of matter in a form we don't yet know - pervasive dark matter needed to explain the motions of the visible in the outer galaxy. What's out there?


Announcement: APOD Editor RJN to open Final Frontier art exhibit in Ireland on August 28
Tomorrow's picture: NGC 7008

 

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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.
2008 August 25

NGC 7008: The Fetus Nebula
Credit & Copyright: Dietmar Hager, Don Goldman, Paul Mortfield Explanation: Compact and round, NGC 7008 is recognized as a planetary nebula about 2,800 light-years distant in the nebula rich constellation of Cygnus. This impressive telescopic view shows off NGC 7008's remarkable colors and details by the skillfull combination of broad band and narrow band images from two different telescopes with about 12 hours of total exposure time. The intriguing assortment of features within the nebula's approximately 1 light-year diameter suggest its popular name, the Fetus Nebula, but planetary nebulae are not associated with star birth. Instead, nebulae like NGC 7008 are produced during a brief phase that sun-like stars pass through toward the end of their lives. Ejecting their outer layers, the stars cool to eventually become white dwarf stars, like the star seen near the center of NGC 7008. This colorful image also includes an unrelated but still lovely gold and blue binary star system just below NGC 7008.


Announcement: APOD Editor RJN to open Final Frontier art exhibit in Ireland on August 28
Tomorrow's picture: magnificent star ball

 

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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.
2008 August 26

47 Tuc: A Great Globular Cluster of Stars
Credit & Copyright: Thomas V. Davis (tvdavisastropix.com) Explanation: Stars come in bunches. Of the over 200 globular star clusters that orbit the center of our Milky Way Galaxy, 47 Tucanae is the second brightest globular cluster (behind Omega Centauri). Light takes about 13,000 years to reach us from 47 Tuc which can be seen on the sky near the Small Magellanic Cloud in the southern constellation of Tucana. Also known as NGC 104, the dense cluster is made up of several million stars in a volume only about 120 light-years across. Its population of red giant stars are particularly easy to see in this picture. The globular cluster is also home to exotic x-ray binary star systems.


Announcement: APOD Editor RJN to open Final Frontier art exhibit in Ireland on August 28
Tomorrow's picture: cocoon

 

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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.
2008 August 28

Fermi's First Light
Credit: NASA, DOE, International LAT Team Explanation: Launched on June 11 to explore the universe at extreme energies, the Gamma-ray Large Area Space Telescope has been officially renamed the Fermi Gamma-ray Space Telescope, in honor of Nobel Laureate Enrico Fermi (1901-1954), pioneer in high-energy physics. After testing, Fermi's two instruments, the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope (LAT), are now regularly returning data. Fermi's first map of the gamma-ray sky from the LAT is shown in this false-color image, an all-sky view that looks toward the center of our Milky Way Galaxy with the galactic plane projected across the middle. What shines in the gamma-ray sky? Along the galactic plane, energetic cosmic rays collide with gas and dust to produce the diffuse gamma-ray glow. Strong emission from spinning neutron stars or pulsars, and distant active galaxies known as blazars, can be identified by placing your cursor over the map. A prelude to future discoveries, the remarkable result combines only 4 days of observations, equivalent to a year of observations with the Compton Gamma-ray Observatory mission of the 1990s. In addition to the ability to monitor gamma-ray bursts, the greatly improved sensitivity will allow Fermi to look deeper into the high-energy Universe.


Tomorrow's picture: W5

 

[plachta]

WorldWideTeleskop is best of programs for amateur astronom.

:thum::thum::thum:

 

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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.
2008 August 29

Generations of Stars in W5
Credit Lori Allen, Xavier Koenig (Harvard-Smithsonian CfA) et al., JPL-Caltech, NASA Explanation: Giant star forming region W5 is over 200 light-years across and about 6,500 light-years away in the constellation Cassiopeia. W5's sculpted clouds of cold gas and dust seem to form fantastic shapes in this impressive mosaic of infrared images from the Spitzer Space Telescope. In fact, the area on the right includes the structures previously dubbed the Mountains of Creation. New evidence indicates that successive generations of stars formed in the W5 region in an expanding pattern of triggered star formation. The older, earlier generations of stars seem to cluster near the middle of the enormous cavities, with younger stars seen near the rims. Winds and radiation from the older, central stars likely carve out and compress surrounding interstellar material, triggering the collapse that gave rise to younger, later generations of stars farther out. In the false-color image, heated dust still within the cavities appears red, while the youngest stars are forming in the whitish areas. W5 is also known as IC 1848, and together with IC 1805 it is part of a complex region popularly dubbed the Heart and Soul Nebulae.


Tomorrow's picture: light-weekend

 

[plachta]

 

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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.
2008 August 30

The View from Everest
Credit & Copyright: Roddy Mackenzie Explanation: What would it be like to stand atop the tallest mountain on Earth? To see a full panoramic vista from there, scroll right. Visible are snow peaked mountains near and far, tremendous cliffs, distant plateaus, the tops of clouds, and a dark blue sky. Mt. Everest stands 8.85 kilometers above sea level, roughly the maximum height reached by international airplane flights, but much less than the 300 kilometers achieved by a space shuttle. Hundreds of people have tried and failed to climb the behemoth by foot, a feat first accomplished successfully in 1953. About 1000 people have now made it to the summit. Roddy Mackenzie, who climbed the mountain in 1989, captured the above image. Mt. Everest lies in the Himalaya mountains in the country of Nepal. In the native language of Nepal, the mountain's name is "Sagarmatha" which means "forehead of the sky."


Tomorrow's picture: the view from the Great Wall

 

[miri80]

May not be real... but I like it a lot. It's one of my favorites.

 

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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.
2008 August 31

Eclipse over the Great Wall
Credit & Copyright: Mike Simmons (Astronomers Without Borders, TWAN) Explanation: Contrary to the famous myth, you can't see the Great Wall of China from the Moon ... even during a total solar eclipse. But on August 1 you could see the Moon eclipsing the Sun from the Great Wall. In fact, from this location near the Great Wall's western end, the Moon completely blocked the Sun's overwhelming disk revealing a shimmering solar corona and bright planets in the briefly darkened sky. A main pass, The Great Wall's Jiayuguan Fort, is also silhouetted in the foreground. The pass is the western-most of the wall's passes and the best preserved, initially built around 1372 during the Ming dynasty. The nearby city of Jiayuguan in Gansu Province was an important stop on the Silk Road.


Tomorrow's picture: gas claw

 

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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.
2008 September 1

CG4: A Ruptured Cometary Globule
Credit & Copyright: Mike Sidonio Explanation: Can a gas cloud grab a galaxy? It's not even close. The "claw" of this odd looking "creature" in the above photo is a gas cloud known as a cometary globule. This globule, however, has ruptured. Cometary globules are typically characterized by dusty heads and elongated tails. These features cause cometary globules to have visual similarities to comets, but in reality they are very much different. Globules are frequently the birthplaces of stars, and many show very young stars in their heads. The reason for the rupture in the head of this object is not completely known. The galaxy to the left of the globule is huge, very far in the distance, and only placed near CG4 by chance superposition.


Tomorrow's picture: swirling collision

 

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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.
2008 September 2

NGC 1316: After Galaxies Collide
Credit & Copyright: Martin Pugh Explanation: Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Their investigation indicates that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just above it. Supporting evidence includes the dark dust lanes characteristic of a spiral galaxy, and faint swirls of stars and gas visible in this wide and deep image. What remains unexplained are the unusually small globular star clusters, seen as faint dots on the image. Most elliptical galaxies have more and brighter globular clusters than NGC 1316. Yet the observed globulars are too old to have been created by the recent spiral collision. One hypothesis is that these globulars survive from an even earlier galaxy that was subsumed into NGC 1316.


Tomorrow's picture: looking back

 

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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.
2008 September 3

31 Million Miles from Planet Earth
Video Credit: Donald J. Lindler, Sigma Space Corporation, GSFC,
Univ. Maryland, EPOCh/DIXI Science Teams Explanation: On July 4th, 2005, the Deep Impact spacecraft directed a probe to impact the nucleus of Comet Tempel 1. Still cruising through the solar system, earlier this year the robotic spacecraft looked back to record a series of images of its home world 31 million miles (50 million kilometers) away. In a sequence from top left to bottom right, these four frames from the video show a rotating Earth. They combine visible and near-infrared image data with enough resolution and contrast to see clouds, oceans, and continents. They also follow a remarkable transit of Earth by its large, natural satellite, the Moon. The Moon's orbital motion carries it across the field of view from left to right. Imaging the Earth from this distant perspective allows astronomers to connect overall variations in brightness at different wavelengths with planetary features. The observations will aid in the search for earth-like planets in other solar systems.


Tomorrow's picture: bicycle nebula

 

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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.
2008 September 4

Spokes in the Helix Nebula
Credit & Copyright: Don Goldman, Sierra Remote Observatories Explanation: At first glance, the Helix Nebula (aka NGC 7293), looks simple and round. But this well-studied example of a planetary nebula, produced near the end of the life of a sun-like star, is now understood to have a surprisingly complex geometry. Its extended loops and comet-shaped features have been explored in Hubble Space Telescope images. Still, a 16-inch diameter telescope and camera with broad and narrow band filters was used to create this sharp view of the Helix. The color composite also reveals the nebula's intriguing details, including light-year long, bluegreen radial stripes or spokes that give it the appearance of a cosmic bicycle wheel. The spoke features seem to indicate that the Helix Nebula is itself an old and evolved planetary nebula. The Helix is a mere seven hundred light years from Earth, in the constellation Aquarius.


Tomorrow's picture: road trip

 

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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.
2008 September 5

Milky Way Road Trip
Credit & Copyright: Tunç Tezel (TWAN) Explanation: In search of planets and the summer Milky Way, astronomer Tunç Tezel took an evening road trip. Last Saturday, after driving the winding road up Uludag, a mountain near Bursa, Turkey, he was rewarded by this beautiful skyview to the south. Near the center, bright planet Jupiter outshines the city lights below and the stars of the constellation Sagittarius. Above the mountain peaks, an arcing cloud bank seems to lead to the Milky Way's own cloudy apparition plunging into the distant horizon. In Turkish, Uludag means Great Mountain. Uludag was known in ancient times as the Mysian Olympus.


Tomorrow's picture: starlings

 

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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.
2008 September 10

The Anthe Arc around Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: What created this unusual partial ring around Saturn? Discovered last year, the arc was captured in clear detail only two months ago by the Saturn-orbiting Cassini spacecraft. Since the arc occupies the same orbit as the small moon Anthe, a leading hypothesis holds that the arc was created by, and is replenished by, meteor impacts on Anthe. Similar arcs have been previously discovered, including an arc associated with the small Saturnian moon Methone, one arc related to Saturn's G ring, and several arcs orbiting Neptune. Pictured above, Anthe, only two kilometers across, is seen as the bright point near the top of the Anthe arc. The Anthe arc was imaged by the robotic space probe as it swooped to within 1.5 million kilometers of the small moon.


Tomorrow's picture: rain above the clouds

 

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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.
2008 September 11

Mountain Top Meteors
Credit & Copyright: Alex Tudorica, Romanian Society for Meteors and Astronomy
Faculty of Physics, Bucharest University Explanation: A mountain top above the clouds and light-polluted cities was a good place to go to watch this August's Perseid meteor shower. In fact, this composite picture from one of the highest points in Romania, the Omu summit (2,507 meters) in the Southern Carpathian Mountains, captures about 20 of the shower's bright streaks against a starry night sky. The cosmic debris stream that creates the shower is composed of dust particles moving along parallel paths, following the orbit of their parent comet Swift-Tuttle. Looking toward the shower's radiant point in the constellation Perseus, perspective causes the parallel meteor streaks to appear to diverge. But looking directly away from the radiant point, as in this view, perspective actually makes the Perseid meteors seem to be converging toward a point below the horizon.


Tomorrow's picture: southern sky

 

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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.
2008 September 12

Planets over Perth
Credit & Copyright: John Goldsmith, Celestial Visions exhibition, TWAN Explanation: A bright trio of terrestrial planets was joined by a young Moon on September 1st, in planet Earth's early evening skies. In this view of the celestial gathering from Perth, Western Australia, the Moon's sunlit crescent is nearly horizontal at Perth's southern latitude of about 32 degrees. Venus, then Mercury, and finally Mars shine above colorful city lights on the far shore of the Swan River. The six unlit towers on the left surround a large cricket stadium. For now, the planetary trio still lingers low in the west just after sunset. But in the coming days Venus will move farther from the Sun, climbing higher after sunset, while Mercury and Mars will steadily sink into the glare along the western horizon.


Tomorrow's picture: Triangulum Galaxy

 

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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.
2008 September 13

M33: Triangulum Galaxy
Credit & Copyright: Paul Mortfield, Stefano Cancelli Explanation: The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this sharp, detailed image nicely shows off M33's blue star clusters and pinkish star forming regions that trace the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 1 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.

Note: Free Astronomy Course Taught Online by an APOD Editor

Tomorrow's picture: heart and soul

 

[RIDER]

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.
2008 September 14

The Heart and Soul Nebulas
Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator;
Color Composite: Davide De Martin (Skyfactory) Explanation: Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the above zoomable view on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible above in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focussed on how massive stars form and how they affect their environment.

Note: Free Astronomy Course Taught Online by an APOD Editor

Tomorrow's picture: hubble ribbon