NASA Astronomy Picture of the Day

[frogfish]

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.

2006 April 18

NGC 246 and the Dying Star

Credit: Gemini South GMOS, Travis Rector (Univ. Alaska)

Explanation: Appropriately nicknamed "the Skull Nebula", planetary nebula NGC 246 really does surround a dying star some 1,600 light-years away in the constellation Cetus. Expelled over a period of thousands of years, the lovely, intricate nebula is the outer atmosphere of a once sun-like star. The expanding outer atmosphere is interacting with the gas and dust in the interstellar medium, while the star itself, the fainter member of the binary star system seen at the nebula's center, is entering its final phase of evolution, becoming a dense, hot white dwarf. Star and nebula are moving rapidly toward the top of the detailed view, as suggested by the nebula's brighter, upper, leading edge. The sharp image spans just over 2.5 light-years at the estimated distance of NGC 246 and also reveals distant background galaxies, some visible right through the nebula along the bottom.

[_Nyx_]

That's an awesome picture

[nativechick1989]

Wow . . that is a beautiful photo . .

[DR. YO]

Good find.

[Nirwana]

Great picture.

[frogfish]

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.

2006 April 19

Mars and the Star Clusters

Credit & Copyright: Chris Schur

Explanation: This evening's skyscape includes a view similar to this one, recorded in western skies on April 16 - an orange-hued planet Mars wandering near rich open star cluster M35. Also notable is fainter star cluster NGC 2158, just above and left of M35. The grouping appears near the "foot stars" of the constellation Gemini, but of course Mars is in the foreground, just over 14 light-minutes from planet Earth. The hundreds of stars in cluster M35 are more like 3,000 light-years distant. NGC 2158 is farther still, about 16,000 light-years away and is much more compact than M35. The color image shows off the contrast between hot blue stars and cooler yellowish stars within the confines of M35. But the stars of NGC 2158 are much older, and that cluster's light is definitely dominated by the orange glow of cool giant stars, making an interesting visual comparison to ruddy-colored Mars.

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Edited to re-size large image. To see the original sized image click on the picture above.

Waspie_Dwarf

Edited April 28, 2006 by Waspie_Dwarf

[Sharm]

Have you seen this?

Hubble Telescope Image Site

[frogfish]

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.

2006 April 20

A Dust Cloud in NGC 281

Credit: NASA, ESA, The Hubble Heritage Team, (STScI / AURA) and P. McCullough (STScI)

Explanation: Stars themselves can create huge and intricate dust sculptures from the dense and dark molecular clouds from which they are born. The tools the stars use to carve their detailed works are high energy light and fast stellar winds. The heat they generate evaporates the dark molecular dust as well as causing ambient hydrogen gas to disperse and glow red. Pictured above, a new open cluster of stars designated IC 1590 is nearing completion around the intricate interstellar mountain named NGC 281. The dust cloud NGC 281, dubbed the Pacman nebula because of its overall shape, is classified as a dense Bok Globule that lies about 10,000 light years distant.

[zandore]

Astronomy Picture of the Day Archive: APOD Archive

It goes back to June 16 1995

[frogfish]

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.

2006 April 21

NGC 253: Dusty Island Universe

Credit & Copyright: R. Jay GaBany (Cosmotography.com)

Explanation: Shiny NGC 253, sometimes called the Silver Dollar Galaxy, is one of the brightest spiral galaxies visible - and also one of the dustiest. First swept up in 1783 by mathematician and astronomer Caroline Herschel, the dusty island universe lies a mere 10 million light-years away in the southern constellation Sculptor. About 70 thousand light-years across, NGC 253 is the largest member of the Sculptor Group of Galaxies, the nearest to our own Local Group of Galaxies. In addition to its spiral dust lanes, striking tendrils of dust seem to be rising from the galactic disk in this gorgeous view. The high dust content accompanies frantic star formation, giving NGC 253 the designation of a starburst galaxy. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center.

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Edited to re-size large image. To see the original sized image click on the picture above.

Waspie_Dwarf

Edited April 28, 2006 by Waspie_Dwarf

[Universal Absurdity]

I get all my desktops from here

[frogfish]

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.

2006 April 22

Z is for Mars

Credit & Copyright: Tunc Tezel

Explanation: This composite of images spaced about a week apart - from late July 2005 (bottom right) through February 2006 (top left) - traces the retrograde motion of ruddy-colored Mars through planet Earth's night sky. On November 7th, 2005 the Red Planet was opposite the Sun in Earth's sky (at opposition). That date occurred at the center of this series with Mars near its closest and brightest. But Mars didn't actually reverse the direction of its orbit to trace out the Z-shape. Instead, the apparent backwards or retrograde motion with respect to the background stars is a reflection of the motion of the Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. The familiar Pleiades star cluster lies at the upper left.

Indeed UA, it is a very nice gallery.

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Edited to re-size large image. To see the original sized image click on the picture above.

Waspie_Dwarf

Edited April 28, 2006 by Waspie_Dwarf

[frogfish]

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.

2006 April 23

The Solar Spectrum

Credit & Copyright: Nigel Sharp (NSF), FTS, NSO, KPNO, AURA, NSF

Explanation: It is still not known why the Sun's light is missing some colors. Shown above are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device. The above spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our yellow-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light. The dark patches in the above spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine what gasses compose the Sun. Helium, for example, was first discovered in 1870 on a solar spectrum and only later found here on Earth. Today, the majority of spectral absorption lines have been identified - but not all.

[kaknelson]

I adore Astronomy ! Good post froggy.

- Multiple Generations of Stars.

[frogfish]

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.

2006 April 24

Star Clouds over Arizona

Credit & Copyright: Ulrich Beinert

Explanation: The clouds in the foreground are much different than the clouds in the background. In the foreground are a photogenic deck of Earth-based water clouds. The long exposure used to create the above photograph makes the light from the left, reflected from Phoenix, Arizona, USA, appear like a sunset. Far in the distance, however, are star clouds from the disk of our Milky Way Galaxy. Billions of stars like our Sun live there, circling our Galactic center every 200 million years. Contrast between the water clouds and the star clouds has been digitally enhanced. Between the two, visible on the upper right, is the planet Jupiter.

[frogfish]

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.

2006 April 25

M82: Galaxy with a Supergalactic Wind

Credit: NASA, ESA, The Hubble Heritage Team, (STScI / AURA)

Acknowledgement: M. Mountain (STScI), P. Puxley (NSF), J. Gallagher (U. Wisconsin)

Explanation: What's lighting up the Cigar Galaxy? M82, as this irregular galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardly expanding gas, however. Recent evidence indicates that this gas is being driven out by the combined emerging particle winds of many stars, together creating a galactic "superwind." The above photographic mosaic, released yesterday to commemorate the sixteenth anniversary of the Hubble Space Telescope, highlights a specific color of red light strongly emitted by ionized hydrogen gas, showing detailed filaments of this gas. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, and can be seen in visible light with a small telescope towards the constellation of Ursa Major.

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Edited to re-size large image. To see the original sized image click on the picture above.

Waspie_Dwarf

Edited April 28, 2006 by Waspie_Dwarf

[frogfish]

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.

2006 April 26

Crumbling Comet Schwassmann-Wachmann 3 Approaches

Credit: FORS1, 8.2-meter VLT Kueyen, ESO

Explanation: A crumbling comet will soon pass near the Earth. Comet 73P/Schwassmann-Wachmann 3 is brightening and may even be visible to the unaided eye when the fragmented comet zooms past Earth during the middle of next month. Still, the small comet poses no Earth hazard, since it will pass the Earth at about 25 times the distance of the Moon. Exactly how bright Comet Schwassman-Wachmann 3 will get is unknown. It is even possible, althought unlikely, that debris from the comet will have spread out enough to cause a notable meteor shower. Pictured above, Fragment B of Comet Schwassman-Wachmann 3 was photographed two nights ago by a 8.2-meter Very Large Telescope in Chile. Visible to the lower right of the large B fragment are many mini-comets that have broken off and now orbit the Sun separately. Each mini-comet itself sheds gas and dust and so appears to have its own hazy coma. The comet will pass closest to the Sun on June 7.

[Waspie_Dwarf]

↑The full ESO press release and other images of this comet can be found on this thread: Comet P73/Schwassmann-Wachmann 3 Edited April 28, 2006 by Waspie_Dwarf

[frogfish]

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.

2006 April 27

NGC 4696: Energy from a Black Hole

Composite Image Credit: X-ray in red - NASA/ CXC/S.Allen (Kavli Inst., Stanford) et al.;

Radio in blue - NRAO/G.Taylor (VLA); Infrared in green - NASA/ESA/W.Harris (McMaster Univ.)

Explanation: In many cosmic environments, when material falls toward a black hole energy is produced as some of the matter is blasted back out in jets. In fact, such black hole "engines" appear to be the most efficient in the Universe, at least on a galactic scale. This composite image illustrates one example of an elliptical galaxy with an efficient black hole engine, NGC 4696. The large galaxy is the brightest member of the Centaurus galaxy cluster, some 150 million light-years away. Exploring NGC 4696 in x-rays (red) astronomers can measure the rate at which infalling matter fuels the supermassive black hole and compare it to the energy output in the jets to produce giant radio emitting bubbles. The bubbles, shown here in blue, are about 10,000 light-years across. The results confirm that the process is much more efficient than producing energy through nuclear reactions - not to mention using fossil fuels. Astronomers also suggest that as the black hole pumps out energy and heats the surrounding gas, star formation is ultimately shut off, limiting the size of large galaxies like NGC 4696.

[kaknelson]

In 1995, the majestic spiral galaxy NGC 4414 was imaged by the Hubble Space Telescope as part of the HST Key Project on the Extragalactic Distance Scale. An international team of astronomers, led by Dr. Wendy Freedman of the Observatories of the Carnegie Institution of Washington, observed this galaxy on 13 different occasions over the course of two months. Images were obtained with Hubble's Wide Field Planetary Camera 2 (WFPC2) through three different color filters. Based on their discovery and careful brightness measurements of variable stars in NGC 4414, the Key Project astronomers were able to make an accurate determination of the distance to the galaxy. The resulting distance to NGC 4414, 19.1 megaparsecs or about 60 million light-years, along with similarly determined distances to other nearby galaxies, contributes to astronomers' overall knowledge of the rate of expansion of the universe. In 1999, the Hubble Heritage Team revisited NGC 4414 and completed its portrait by observing the other half with the same filters as were used in 1995. The end result is a stunning full-color look at the entire dusty spiral galaxy. The new Hubble picture shows that the central regions of this galaxy, as is typical of most spirals, contain primarily older, yellow and red stars. The outer spiral arms are considerably bluer due to ongoing formation of young, blue stars, the brightest of which can be seen individually at the high resolution provided by the Hubble camera. The arms are also very rich in clouds of interstellar dust, seen as dark patches and streaks silhouetted against the starlight.

[Waspie_Dwarf]

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.

2006 April 28

NGC 7635: Bubble in a Cosmic Sea

Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator

Color Composite: Davide De Martin (Skyfactory)

Explanation: Seemingly adrift in a cosmic sea of stars and glowing gas, the delicate, floating apparition near the center (next to a blue tinted star) of this widefield view is cataloged as NGC 7635 - The Bubble Nebula. A mere 10 light-years wide, the tiny Bubble Nebula and the larger complex of interstellar gas and dust clouds are found about 11,000 light-years distant, straddling the boundary between the parental constellations Cepheus and Cassiopeia. Also included in the breathtaking vista is open star cluster M52 (upper left), some 5,000 light-years away. The digital color picture is based on photographic plates taken at the Palomar Observatory between 1992 and 1997. This cropped version spans about 2.7 degrees on the sky corresponding to a width of just over 500 light-years at the estimated distance of the Bubble Nebula.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

Source: APOD

Edited April 28, 2006 by Waspie_Dwarf

[Guest Lottie]

These images are truly humbling.

[Waspie_Dwarf]

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.

2006 April 29

Skylab Over Earth

Credit: Skylab, NASA

Explanation: Skylab was an orbiting laboratory launched by a in May 1973. Skylab, pictured above, was visited three times by NASA astronauts who sometimes stayed as long as two and a half months. Many scientific tests were performed on Skylab, including astronomical observations in ultraviolet and X-ray light. Some of these observations yielded valuable information about Comet Kohoutek, our Sun and about the mysterious X-ray background - radiation that comes from all over the sky. Skylab fell back to earth on 11 July 1979.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

Source: APOD

Edited April 29, 2006 by Waspie_Dwarf

[MID]

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.

2006 April 29

Skylab Over Earth

Credit: Skylab, NASA

Explanation: Skylab was an orbiting laboratory launched by a in May 1973. Skylab, pictured above, was visited three times by NASA astronauts who sometimes stayed as long as two and a half months. Many scientific tests were performed on Skylab, including astronomical observations in ultraviolet and X-ray light. Some of these observations yielded valuable information about Comet Kohoutek, our Sun and about the mysterious X-ray background - radiation that comes from all over the sky. Skylab fell back to earth on 11 July 1979.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)

Source: APOD

Ah, a little nostalgia...she was a heck of a machine, Skylab.

[Hazzard]

Greate pictures.