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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- A Space Shuttle Over Los Angeles

    09/25/2012 9:17:10 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | September 26, 2012 | (see photo credit)
    Explanation: It's not every day that a space shuttle lands at LAX. Although this was a first for the major Los Angeles airport hub, it was a last for the space shuttle Endeavour, as it completed its tour of California skies and landed, albeit atop a 747, for the last time. During its last flight the iconic shuttle and its chase planes were photographed near several of California's own icons including the Golden Gate Bridge in San Francisco, the Hollywood Sign, and the skyline of Los Angeles. Previously, in May, the space shuttle Enterprise was captured passing behind several of...
  • Astronomy Picture of the Day -- Unusual Spheres on Mars

    09/24/2012 9:14:37 PM PDT · by SunkenCiv · 40 replies
    NASA ^ | September 25, 2012 | (see photo credit)
    Explanation: Why are these strange little spheres on Mars? The robotic rover Opportunity chanced across these unusually shaped beads earlier this month while exploring a place named Kirkwood near the rim of Mars' Endeavor Crater. The above image taken by Opportunity's Microscopic Imager shows that some ground near the rover is filled with these unusual spheres, each spanning only about 3 millimeters. At first glance, the sometimes-fractured balls appear similar to the small rocks dubbed blueberries seen by Opportunity eight years ago, but these spheres are densely compacted and have little iron content. Although it is thought that these orbs...
  • Astronomy Picture of the Day -- NGC 2736: The Pencil Nebula

    09/24/2012 6:52:23 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | September 24, 2012 | (see photo credit)
    Explanation: This shock wave plows through space at over 500,000 kilometers per hour. Moving toward to bottom of this beautifully detailed color composite, the thin, braided filaments are actually long ripples in a sheet of glowing gas seen almost edge on. Cataloged as NGC 2736, its narrow appearance suggests its popular name, the Pencil Nebula. About 5 light-years long and a mere 800 light-years away, the Pencil Nebula is only a small part of the Vela supernova remnant. The Vela remnant itself is around 100 light-years in diameter and is the expanding debris cloud of a star that was seen...
  • Astronomy Picture of the Day -- Equinox: The Sun from Solstice to Solstice

    09/22/2012 9:16:55 PM PDT · by SunkenCiv · 17 replies
    NASA ^ | September 23, 2012 | (see photo credit)
    Explanation: Yesterday was an equinox, a date when day and night are equal. Today, and every day until the next equinox, the night will be longer than the day in Earth's northern hemisphere, and the day will be longer than the night in Earth's southern hemisphere. An equinox occurs midway between the two solstices, when the days and nights are the least equal. The picture is a composite of hourly images taken of the Sun above Bursa, Turkey on key days from solstice to equinox to solstice. The bottom Sun band was taken during the winter solstice in 2007 December,...
  • Astronomy Picture of the Day -- Austrian Analemma

    09/22/2012 8:57:01 PM PDT · by SunkenCiv · 11 replies
    NASA ^ | September 22, 2012 | (see photo credit)
    Explanation: Today, the Sun crosses the celestial equator heading south at 14:49 Universal Time. An equinox (equal night), this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. With the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. To celebrate, consider this careful record of the Sun's yearly journey through southern Austrian skies. The scene is composed of images made at the same time each day, capturing the Sun's position on dates from September 29, 2011 through September 9, 2012. The...
  • Astronomy Picture of the Day -- September's Aurora

    09/21/2012 3:29:42 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | September 21, 2012 | (see photo credit)
    Explanation: September's equinox arrives tomorrow as the Sun crosses the celestial equator heading south. The event marks the astronomical beginning of spring in the southern hemisphere and autumn in the north. And though the connection is still puzzling, the equinox seasons bring an increase in geomagnetic storms. So as northern nights grow longer, the equinox also heralds the arrival of a good season for aurora hunters. Recorded on September 20, these colorful northern lights were captured with camera and wide-angle lens near the Norwegian Sea coast outside Tromsø in Northern Norway. Shining at altitudes of 100 kilometers or so, the...
  • Astronomy Picture of the Day -- Sunrise Analemma (with a little extra)

    09/20/2012 3:46:22 AM PDT · by SunkenCiv · 11 replies
    NASA ^ | September 20, 2012 | (see photo credit)
    Explanation: An analemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. In this case, 17 individual images taken at 0231 UT on dates between April 2 and September 16 follow half the analemma curve, looking east toward the rising sun and the Caspian sea from the boardwalk in the port city of Baku, Azerbaijan. With the sun nearest the horizon, those dates almost span the period between the 2012 equinoxes on March 20 and September 22. The northern summer Solstice on June 20...
  • Astronomy Picture of the Day -- Leaving Vesta

    09/19/2012 6:23:23 PM PDT · by SunkenCiv · 14 replies
    NASA ^ | September 19, 2012 | (see photo credit)
    Explanation: Next stop: Ceres. Last week the robotic Dawn spacecraft ended its year-long mission to asteroid Vesta, becoming the first spacecraft ever to visit this far off world located between Mars and Jupiter, in the Solar System's main asteroid belt. Many of the best images taken by Dawn at Vesta have been compiled into the above encompassing view. Vesta shows evidence of being a leftover from the early years of our Solar System, a building block for rocky planets like Earth. Vesta's ancient surface shows heavy cratering and long troughs likely created by huge impacts. The minor planet's low gravity...
  • Astronomy Picture of the Day -- Orbiting Astronaut Self-Portrait

    09/18/2012 3:51:36 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | September 18, 2012 | (see photo credit)
    Explanation: Is it art? Earlier this month, space station astronaut Aki Hoshide (Japan) recorded this striking image while helping to augment the capabilities of the Earth-orbiting International Space Station (ISS). Visible in this outworldly assemblage is the Sun, the Earth, two portions of a robotic arm, an astronaut's spacesuit, the deep darkness of space, and the unusual camera taking the picture. This image joins other historic -- and possibly artistic -- self-portraits taken previously in space. The Expedition 32 mission ended yesterday when an attached capsule undocked with the ISS and returned some of the crew to Earth.
  • Astronomy Picture of the Day -- A Solar Filament Erupts [Wow!]

    09/17/2012 3:14:33 PM PDT · by SunkenCiv · 16 replies
    NASA ^ | September 17, 2012 | (see photo credit)
    Explanation: What's happened to our Sun? Nothing very unusual -- it just threw a filament. At the end of last month, a long standing solar filament suddenly erupted into space producing an energetic Coronal Mass Ejection (CME). The filament had been held up for days by the Sun's ever changing magnetic field and the timing of the eruption was unexpected. Watched closely by the Sun-orbiting Solar Dynamics Observatory, the resulting explosion shot electrons and ions into the Solar System, some of which arrived at Earth three days later and impacted Earth's magnetosphere, causing visible aurorae. Loops of plasma surrounding an...
  • Astronomy Picture of the Day -- Saturn: Bright Tethys and Ancient Rings

    09/16/2012 8:37:42 AM PDT · by SunkenCiv · 14 replies
    NASA ^ | September 16, 2012 | (see photo credit)
    Explanation: How old are Saturn's rings? No one is quite sure. One possibility is that the rings formed relatively recently in our Solar System's history, perhaps only about 100 million years ago when a moon-sized object broke up near Saturn. Evidence for a young ring age includes a basic stability analysis for rings, and the fact that the rings are so bright and relatively unaffected by numerous small dark meteor impacts. More recent evidence, however, raises the possibility that some of Saturn's rings may be billions of years old and so almost as old as Saturn itself. Inspection of images...
  • Astronomy Picture of the Day -- Ring Nebula Drawn

    09/15/2012 10:55:01 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | September 15, 2012 | (see photo credit)
    Explanation: A planetary nebula with a simple symmetry familiar to telescopic sky gazers, the Ring Nebula (M57) is some 2,000 light-years away in the musical constellation Lyra. Hints of changing colors and subtle details are brought out in this remarkable sketch of the cosmic ring. The sketch was made with 800x magnification and excellent seeing conditions directly at the eyepiece of a 40 inch reflecting telescope. Colored pencils on white paper were used to create the original drawing, shown here digitally scanned with an inverted palette applied. About one light-year across, the nebula is composed of outer layers expelled from...
  • Astronomy Picture of the Day -- Elliptical M60, Spiral NGC 4647

    09/15/2012 10:53:41 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | September 14, 2012 | (see photo credit)
    Explanation: Giant elliptical galaxy M60 and spiral galaxy NGC 4647 do look like an odd couple in this sharp cosmic portrait from the Hubble Space Telescope. But they are found in a region of space where galaxies tend to gather, on the eastern side of the nearby Virgo Galaxy Cluster. About 54 million light-years distant, bright M60's simpler egg-like shape is created by its randomly swarming older stars, while NGC 4647's young blue stars, gas and dust are organized into winding arms rotating in a flattened disk. Spiral NGC 4647 is estimated to be more distant than M60, some 63...
  • Astronomy Picture of the Day -- Cocoon Nebula Wide Field

    09/12/2012 9:18:50 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 13, 2012 | (see photo credit)
    Explanation: In this crowded starfield covering over 2 degrees within the high flying constellation Cygnus, the eye is drawn to the Cocoon Nebula. A compact star forming region, the cosmic Cocoon punctuates a long trail of obscuring interstellar dust clouds. Cataloged as IC 5146, the nebula is nearly 15 light-years wide, located some 4,000 light years away. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by the young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula...
  • Astronomy Picture of the Day -- M7: Open Star Cluster in Scorpius

    09/12/2012 8:46:10 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 12, 2012 | (see photo credit)
    Explanation: M7 is one of the most prominent open clusters of stars on the sky. The cluster, dominated by bright blue stars, can be seen with the naked eye in a dark sky in the tail of the constellation of the Scorpion (Scorpius). M7 contains about 100 stars in total, is about 200 million years old, spans 25 light-years across, and lies about 1000 light-years away. The above deep exposure was taken from Hakos Farm in Namibia. The M7 star cluster has been known since ancient times, being noted by Ptolemy in the year 130 AD. Also visible are a...
  • Astronomy Picture of the Day -- Milky Way Over the Bungle Bungles

    09/11/2012 4:21:41 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | September 11, 2012 | (see photo credit)
    Explanation: Which part of this picture do you find more interesting -- the land or the sky? Advocates for the land might cite the beauty of the ancient domes of the Bungle Bungle Range in Western Australia. These picturesque domes appear as huge layered beehives and are made of sandstones and conglomerates deposited over 350 million years ago. Advocates for the sky might laud the beauty of the Milky Way's central band shown arching from horizon to horizon. The photogenic Milky Way band formed over 10 billion years ago and now includes many well-known nebulae and bright stars. Fortunately, you...
  • Astronomy Picture of the Day -- Curiosity on the Move

    09/10/2012 2:31:54 PM PDT · by SunkenCiv · 15 replies
    NASA ^ | September 10, 2012 | (see photo credit)
    Explanation: Curiosity is on the move across Mars -- but where is it going? The car-sized rover's path after 29 Martian days on the surface is shown on the above map. Curiosity is still almost 300 meters from its first major destination, though, a meeting of different types of terrain called Glenelg and visible on the image right. It may take Curiosity two months or so to get to Glenelg as it stops to inspect interesting rocks or landscape features along the way. The above image was taken about one week ago from high up by the HiRise camera onboard...
  • Astronomy Picture of the Day -- Wisps Surrounding the Horsehead Nebula

    09/08/2012 9:16:56 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | September 09, 2012 | (see photo credit)
    Explanation: The famous Horsehead Nebula in Orion is not alone. A deep exposure shows that the dark familiar shaped indentation, visible just below center, is part of a vast complex of absorbing dust and glowing gas. To bring out details of the Horsehead's pasture, amateur astronomers at the Star Shadow Remote Observatory in New Mexico, USA fixed a small telescope on the region for over seven hours filtering out all but a very specific color of red light emitted by hydrogen. They then added the image to a full color frame taken over three hours. The resulting spectacular picture details...
  • Astronomy Picture of the Day -- Cosmic Rays at Voyager 1

    09/08/2012 9:16:52 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | September 08, 2012 | (see photo credit)
    Explanation: Launched on a grand tour of the outer planets in 1977, by good fortune the twin Voyager spacecraft were also headed in the general direction of the Sun's motion relative to nearby stars. Thirty five years later, Voyager 1 appears to be nearing the boundary of the Sun's heliosphere and interstellar space. Of course the heliosphere is the realm of the Sun defined by the influence of the solar wind and the Sun's magnetic field. But how can you tell when your spacecraft crosses the boundary into interstellar space? One clue would be a sudden increase in the detection...
  • Astronomy Picture of the Day -- IC 4628: The Prawn Nebula

    09/06/2012 9:14:16 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | September 07, 2012 | (see photo credit)
    Explanation: South of Antares, in the tail of the nebula-rich constellation Scorpius, lies emission nebula IC 4628. Nearby hot, massive stars, millions of years young, radiate the nebula with invisible ultraviolet light, stripping electrons from atoms. The electrons eventually recombine with the atoms to produce the visible nebular glow, dominated by the red emission of hydrogen. At an estimated distance of 6,000 light-years, the region shown is about 250 light-years across, spanning an area equivalent to four full moons on the sky. The nebula is also cataloged as Gum 56 for Australian astronomer Colin Stanley Gum, but seafood-loving astronomers might...