Astronomy Picture of the Day

poopoy said:

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.

2010 May 2

The Coma Cluster of Galaxies
Credit & Copyright: Dean Rowe


Explanation: Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma and other clusters are ellipticals, while most galaxies outside of clusters are spirals. The nature of Coma's X-ray emission is still being investigated.

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poopoy said:

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.

2010 May 3

Spiral Galaxy NGC 3190 Almost Sideways
Credit: Data - Hubble Legacy Archive, ESA, NASA Processing - Robert Gendler


Explanation: Some spiral galaxies are seen almost sideways. NGC 3190, one such galaxy, is the largest member of the Hickson 44 Group, one of the nearer groups of galaxies to our own Local Group of galaxies. Pictured above, finely textured dust lanes surround the brightly glowing center of this picturesque spiral. Gravitational tidal interactions with other members of its group have likely caused the spiral arms of NGC 3190 to appear asymmetric around the center, while the galactic disk also appears warped. NGC 3190 spans about 75,000 light years across and is visible with a small telescope toward the constellation of the Lion (Leo).

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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.
2010 May 4

A Hall of Mountain Glory
Credit & Copyright: A. Tudorica (ISS Romania) Explanation: If you tried to enter this hall of fog, you would find it dissipates around you. The hall is actually an the mountain from which this picture was taken. Known as "the glory", the phenomenon is frequently seen from airplanes. The ring's center is not visible, but if it were, the shadow of the observer would appear. This shadow would likely change as clouds passed, creating a faux moving giant known as the Brocken Spectre. Pictured above, several concentric rings of the glory appear to create a hall for this mountain king. The cause of the glory has only been understood recently and is relatively complex. Briefly, small droplets of water reflect, refract, and diffract sunlight backwards towards the Sun. The phenomenon has a counterpart in astronomy, where looking out from planet Earth in the direction opposite the Sun yields a bright spot called the gegenschein.

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.
2010 May 5

The Faces of Mars
Acknowledgement: Serge Vieillard, Julien Vandermarlière
(Drawing Credit and Copyright as shown.) Explanation: Enthusiastic astro-artists ranging from expert to beginner, the youngest age 10, all contributed their work to this entertaining panel featuring different faces of Mars. Their sketches are all based on telescopic views of the Red Planet from earlier this year, near its 2010 opposition. Mars offers the best telescopic views at opposition, since that's when it is closest and opposite the Sun in planet Earth's sky. Arranged in a spiral pattern, the sketches are positioned to follow the planet's rotation. No canals are visible(!), but large surface markings such as the dramatic, dark Syrtis Major are easily identified. As often seen through an astronomical telescope eyepiece, the planet's orientation is inverted, with Mars' north polar cap at the bottom.

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.
2010 May 7

The Antennae
Credit & Copyright: Star Shadows Remote Observatory and PROMPT/CTIO
(Jack Harvey, Steve Mazlin, Rick Gilbert, and Daniel Verschatse) Explanation: Some 60 million light-years away in the southerly constellation Corvus, two large galaxies collided. But the stars in the two galaxies cataloged as NGC 4038 and NGC 4039 don't collide in the course of the ponderous, billion year or so long event. Instead, their large clouds of molecular gas and dust do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning about 500 thousand light-years, this stunning view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. Of course, the visual appearance of the far-flung arcing structures gives the galaxy pair its popular name - The Antennae.

http://www.sat-universe.com/redirector.php?url=http://apod.nasa.gov/apod/archivepix.html 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.
2010 May 9

Halo of the Cat's Eye
Credit & Copyright: R. Corradi (Isaac Newton Group), Nordic Optical Telescope Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula. Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows extended emission from the nebula. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. Only much more recently however, have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the [ame="http://www.youtube.com/watch?v=tw0VJ1K93PM"]outer filamentary portions[/ame] of this halo to be 50,000 to 90,000 years.

Tomorrow's picture: open loop

poopoy said:

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.

2010 May 9

Halo of the Cat's Eye
Credit & Copyright: R. Corradi (Isaac Newton Group), Nordic Optical Telescope

Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its haunting symmetries are seen in the very central region of this stunning false-color picture, processed to reveal the enormous but extremely faint halo of gaseous material, over three light-years across, which surrounds the brighter, familiar planetary nebula. Made with data from the Nordic Optical Telescope in the Canary Islands, the composite picture shows extended emission from the nebula. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. Only much more recently however, have some planetaries been found to have halos like this one, likely formed of material shrugged off during earlier active episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years.

Take Care All!

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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.
2010 May 10

Large Eruptive Prominence Movie from SDO
Credit: NASA/Goddard/SDO AIA Team Explanation: Sometimes part of the Sun can just explode into space. These explosions might occur as powerful solar flares, coronal mass ejections, or comparatively tame eruptive solar prominences. Pictured above is one of the largest solar prominence eruptions yet observed, one associated with a subsequent coronal mass ejection. The prominence erupted last month and was recorded by several Sun-sensing instruments, including the recently launched Solar Dynamics Observatory (SDO). The above time lapse sequence was captured by SDO and occurred over a few hours. In recent months, our Sun has becoming increasingly active, following a few years of an unusually dormant solar minimum. Over the next few years our Sun is expected to reach solar maximum and exhibit a dramatic increase in sunspots and all types of solar explosions.

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.
2010 May 11

Herschel Crater on Mimas of Saturn
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA Explanation: Why is this giant crater on Mimas oddly colored? Mimas, one of the smaller round moons of Saturn, sports Herschel crater, one of the larger impact craters in the entire Solar System. The robotic Cassini spacecraft now orbiting Saturn took the above image of Herschel crater in unprecedented detail while making a 10,000-kilometer record close pass by the icy world just over one month ago. Shown in contrast-enhanced false color, the above image includes color information from older Mimas images that together show more clearly that Herschel's landscape is colored slightly differently from more heavily cratered terrain nearby. The color difference could yield surface composition clues to the violent history of Mimas. An impact on Mimas much larger than the one that created the 130-kilometer Herschel would likely have destroyed the entire world.