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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- M72: A Globular Cluster of Stars

    08/18/2012 10:09:57 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | August 19, 2012 | (see photo credit)
    Explanation: Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are less than 200 left. Many globular clusters were destroyed over the eons by repeated fateful encounters with each other or the Galactic center. Surviving relics are older than any Earth fossil, older than any other structures in our Galaxy, and limit the universe itself in raw age. There are few, if any, young globular clusters in our Milky Way Galaxy because conditions are not ripe for more to form. Pictured...
  • Astronomy Picture of the Day -- Curiosity on Mars: Still Life with Rover

    08/17/2012 10:47:17 PM PDT · by SunkenCiv · 21 replies
    NASA ^ | August 18, 2012 | (see photo credit)
    Explanation: What does the Curiosity rover look like on Mars? To help find out, NASA engineers digitally synthesized multiple navigation camera images taken last week into what appears to be the view of a single camera. Besides clods of Martian dirt, many of Curiosity's science instruments are visible and appear in good shape. Near the middle of the rover is an augmented reality tag intended to enable smartphones to provide background information. Far in the distance is a wall of Gale Crater. As Curiosity will begin to roll soon, its first destination has now been chosen: an intriguing intersection of...
  • Astronomy Picture of the Day -- Spiral Galaxy NGC 5033

    08/17/2012 6:01:41 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | August 17, 2012 | (see photo credit)
    Explanation: Magnificent island universe NGC 5033 lies some 40 million light-years away in the well-trained northern constellation Canes Venatici. This telescopic portrait reveals striking details of dust lanes winding near the galaxy's bright core and majestic but relatively faint spiral arms. Speckled with pink star forming regions and massive blue star clusters, the arms span over 100,000 light-years, similar in size to our own spiral Milky Way. A well-studied example of the class of Seyfert active galaxies, NGC 5033 has a core that is very bright and variable. The emission is likely powered by a supermassive black hole. The bright...
  • Astronomy Picture of the Day -- NGC 6888: The Crescent Nebula

    08/16/2012 3:40:44 PM PDT · by SunkenCiv · 16 replies
    NASA ^ | August 16, 2012 | (see photo credit)
    Explanation: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This colorful portrait of the nebula uses narrow band image data combined in the Hubble palatte. It shows emission from sulfur, hydrogen, and oxygen atoms in the wind-blown nebula in red, green and blue hues. NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are...
  • Astronomy Picture of the Day -- Curiosity on Mars: A Wall of Gale Crater

    08/15/2012 3:59:37 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | August 15, 2012 | (see photo credit)
    Explanation: If you could stand on Mars, what would you see? The above image is a digitally re-colored approximation of what you might see if the above Martian landscape had occurred on Earth. Images from Mars false-colored in this way are called white balanced and useful for planetary scientists to identify rocks and landforms similar to Earth. The image is a high resolution version of a distant wall of Gale Crater captured by the Curiosity rover that landed on Mars last week. A corresponding true color image exists showing how this scene actually appears on Mars. The robotic Curiosity rover...
  • Astronomy Picture of the Day -- Perseid Meteors and the Milky Way

    08/14/2012 2:29:18 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | August 14, 2012 | (see photo credit)
    Explanation: Where will the next Perseid meteor appear? Sky enthusiasts who trekked outside for the Perseid meteor shower that peaked over the past few days typically had this question on their mind. Six meteors from this past weekend are visible in the above stacked image composite, including one bright fireball streaking along the band of the background Milky Way Galaxy. All Perseid meteors appear to come from the shower radiant in the constellation of Perseus. Early reports about this year's Perseids indicate that as many as 100 meteors per hour were visible from some dark locations during the peak. The...
  • Astronomy Picture of the Day -- A Flight Through the Universe

    08/13/2012 2:33:41 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | August 13, 2012 | (see photo credit)
    Explanation: What would it be like to fly through the universe? Possibly the best simulated video of this yet has been composed from recently-released galaxy data from the Sloan Digital Sky Survey. Every spot in the above video is a galaxy containing billions of stars. Many galaxies are part of huge clusters, long filaments, or small groups, while expansive voids nearly absent of galaxies also exist. The movie starts by flying right through a large nearby cluster of galaxies and later circles the SDSS-captured universe at about 2 billion light years (a redshift of about 0.15) from Earth. Analyses of...
  • Astronomy Picture of the Day -- Spiral Galaxy NGC 4038 in Collision

    08/12/2012 9:22:01 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | August 12, 2012 | (see photo credit)
    Explanation: This galaxy is having a bad millennium. In fact, the past 100 million years haven't been so good, and probably the next billion or so will be quite tumultuous. Visible on the upper left, NGC 4038 used to be a normal spiral galaxy, minding its own business, until NGC 4039, toward its right, crashed into it. The evolving wreckage, known famously as the Antennae, is pictured above. As gravity restructures each galaxy, clouds of gas slam into each other, bright blue knots of stars form, massive stars form and explode, and brown filaments of dust are strewn about. Eventually...
  • Astronomy Picture of the Day -- The First Color Panorama from Mars by Curiosity

    08/11/2012 2:09:57 AM PDT · by SunkenCiv · 38 replies
    NASA ^ | August 11, 2012 | (see photo credit)
    Explanation: You've just landed on Mars and opened your eyes -- what do you see? If you're the Curiosity rover, you see a strange gravelly place with a large mountain in the distance. You've landed on target near the edge of 150-km wide Gale Crater, with Mount Sharp on the horizon being the rise in the crater's center. As a car-sized rover with six wheels and a laser, you prepare yourself to go on a two-year mission of exploration, climbing Mt. Sharp, and looking for signs that Mars once harbored life. Currently you sit motionless, check yourself over, and receive...
  • Astronomy Picture of the Day -- Perseid Below

    08/10/2012 3:55:27 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | August 10, 2012 | (see photo credit)
    Explanation: Denizens of planet Earth watched last year's Perseid meteor shower by looking up into the bright moonlit night sky. But this remarkable view captured on August 13, 2011 by astronaut Ron Garan looks down on a Perseid meteor. From Garan's perspective onboard the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust left from comet Swift-Tuttle heated to incandescence. The glowing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash...
  • Astronomy Picture of the Day -- Mars in the Loop

    08/09/2012 5:26:03 PM PDT · by SunkenCiv · 17 replies
    NASA ^ | August 09, 2012 | (see photo credit)
    Explanation: This composite of images spaced some 5 to 7 days apart from late October 2011 (top right) through early July 2012 (bottom left), traces the retrograde motion of ruddy-colored Mars through planet Earth's night sky. To connect the dots in Mars' retrograde loop, just slide your cursor over the picture (and check out this animation). But Mars didn't actually reverse the direction of its orbit. Instead, the apparent backwards 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...
  • Astronomy Picture of the Day -- Curiosity Drops In

    08/08/2012 6:32:09 PM PDT · by SunkenCiv · 14 replies
    NASA ^ | August 08, 2012 | (see photo credit)
    Explanation: Just as it captured the Phoenix lander parachuting to Mars in 2008, the HiRise camera onboard the Mars Reconnaissance Orbiter (MRO) snapped this picture of the Curiosity rover's spectacular descent toward its landing site on August 5 (PDT). The nearly 16 meter (51 foot) wide parachute and its payload are caught dropping through the thin martian atmosphere above plains just north of the sand dune field that that borders the 5 kilometer high Mt. Sharp in Gale Crater. The MRO spacecraft was about 340 kilometers away when the image was made. From MRO's perspective the parachute is flying at...
  • Astronomy Picture of the Day -- A Wheel on Mars

    08/07/2012 2:31:57 PM PDT · by SunkenCiv · 28 replies
    NASA ^ | August 07, 2012 | (see photo credit)
    Explanation: A wheel attached to NASA's Curiosity rover is firmly on the martian surface in this early picture from the Mars Science Laboratory mission, captured after a successful landing on August 5, 2012 at 10:32pm (PDT). Seen at the lower right of a Hazard Avoidance Camera fisheye wide-angle image, the rover's left rear wheel is 50 centimeters (about 20 inches) in diameter. Part of a spring hinge for the camera's dust cover is just visible in the right corner, while at the upper left is part of the rover's RTG power source. Looking into the Sun across the rock stewn...
  • Astronomy Picture of the Day -- Nocturnal: Scenes from the Southern Night

    08/06/2012 6:19:19 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | August 06, 2012 | (see photo credit)
    Explanation: Have you ever seen the night sky change? It does -- sometimes in beautiful and unexpected ways. To see it, though, usually requires patience. The above award winning video shows several of the possible changes in dramatic fashion with a time lapse video. Visible are sunset-illuminated clouds moving, stars of vivid colors rising, the long tail of a Comet Lovejoy rising, bright satellites crossing, a meteor exploding, a distant lightning storm approaching, skyscapes including the Magellanic Clouds rotating, and a fisheye sky rotating while the foreground becomes illuminated by moonlight. Frequently featuring an artistic human sculpture in the foreground...
  • Astronomy Picture of the Day -- IC 1396: Emission Nebula in Cepheus

    08/05/2012 10:01:09 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | August 05, 2012 | (see photo credit)
    Explanation: Stunning emission nebula IC 1396 mixes glowing cosmic gas and dark dust clouds in the high and far off constellation of Cepheus. Energized by the bright, bluish central star seen here, this star forming region sprawls across hundreds of light-years -- spanning over three degrees on the sky while nearly 3,000 light-years from planet Earth. Among the intriguing dark shapes within IC 1396, the winding Elephant's Trunk nebula lies just below center. The gorgeous color view is a composition of digitized black and white photographic plates recorded through red and blue astronomical filters. The plates were taken using the...
  • Astronomy Picture of the Day -- The Bubble Nebula

    08/05/2012 10:01:09 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | August 04, 2012 | (see photo credit)
    Explanation: Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Above and right of the Bubble's center is a hot, O star, several hundred thousand times more luminous and around 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The...
  • Astronomy Picture of the Day -- Messier 5

    08/03/2012 5:12:10 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | August 03, 2012 | (see photo credit)
    Explanation: "Beautiful Nebula discovered between the Balance [Libra] & the Serpent [Serpens] ..." begins the description of the 5th entry in 18th century astronomer Charles Messier's famous catalog of nebulae and star clusters. Though it appeared to Messier to be fuzzy and round and without stars, Messier 5 (M5) is now known to be a globular star cluster, 100,000 stars or more, bound by gravity and packed into a region around 165 light-years in diameter. It lies some 25,000 light-years away. Roaming the halo of our galaxy, globular star clusters are ancient members of the Milky Way. M5 is one...
  • Astronomy Picture of the Day -- South Pole Star Trails

    08/02/2012 4:09:49 AM PDT · by SunkenCiv · 11 replies
    NASA ^ | August 02, 2012 | (see photo credit)
    Explanation: No star dips below the horizon and the Sun never climbs above it in this remarkable image of 24 hour long star trails. Showing all the trails as complete circles, such an image could be achieved only from two places on planet Earth. This example was recorded during the course of May 1, 2012, the digital camera in a heated box on the roof of MAPO, the Martin A. Pomerantz Observatory at the South Pole. Directly overhead in the faint constellation Octans is the projection of Earth's rotational axis, the South Celestial Pole, at the center of all the...
  • Astronomy Picture of the Day -- The Milky Way Over Monument Valley

    08/01/2012 2:07:49 PM PDT · by SunkenCiv · 18 replies
    NASA ^ | August 01, 2012 | (see photo credit)
    Explanation: You don't have to be at Monument Valley to see the Milky Way arch across the sky like this -- but it helps. Only at Monument Valley USA would you see a picturesque foreground that includes these iconic rock peaks called buttes. Buttes are composed of hard rock left behind after water has eroded away the surrounding soft rock. In the above image taken about two months ago, the closest butte on the left and the butte to its right are known as the Mittens, while Merrick Butte can be seen just further to the right. High overhead stretches...
  • Astronomy Picture of the Day -- Curiosity Before Mars: Seven Minutes of Terror

    07/31/2012 4:57:46 PM PDT · by SunkenCiv · 27 replies
    NASA ^ | July 31, 2012 | (see photo credit)
    Explanation: Next week at this time, there may be an amazing new robotic explorer on Mars. Or there may be a new pile of junk. It all likely depends on many things going correctly in the minutes after the Mars Science Laboratory mission arrives at Mars and attempts to deploy the Curiosity rover from orbit. Arguably the most sophisticated landing yet attempted on the red planet, consecutive precision events will involve a heat shield, a parachute, several rocket maneuvers, and the automatic operation of an unusual device called a Sky Crane. These "Seven Minutes of Terror" -- depicted in the...