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Keyword: astronomy

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  • Astronomy Picture of the Day -- 47 Tuc Near the Small Magellanic Cloud

    12/05/2012 9:44:29 PM PST · by SunkenCiv · 3 replies
    NASA ^ | December 06, 2012 | (see photo credit)
    Explanation: Globular star cluster 47 Tucanae is a jewel of the southern sky. Also known as NGC 104, it roams the halo of our Milky Way Galaxy along with around 200 other globular star clusters. The second brightest globular cluster (after Omega Centauri) as seen from planet Earth, it lies about 13,000 light-years away and can be spotted naked-eye near the Small Magellanic Cloud (SMC) in the constellation of the Toucan. Of course, the SMC is some 210,000 light-years distant, a satellite galaxy of our Milky Way and not physically close to 47 Tuc. Stars on the outskirts of the...
  • Astronomy Picture of the Day -- Plasma Jets from Radio Galaxy Hercules A

    12/05/2012 9:30:09 PM PST · by SunkenCiv · 19 replies
    NASA ^ | December 05, 2012 | (see photo credit)
    Explanation: Why does this galaxy emit such spectacular jets? No one is sure, but it is likely related to an active supermassive black hole at its center. The galaxy at the image center, Hercules A, appears to be a relatively normal elliptical galaxy in visible light. When imaged in radio waves, however, tremendous plasma jets over one million light years long appear. Detailed analyses indicate that the central galaxy, also known as 3C 348, is actually over 1,000 times more massive than our Milky Way Galaxy, and the central black hole is nearly 1,000 times more massive than the black...
  • Astronomy Picture of the Day -- In the Center of Saturn's North Polar Vortex

    12/04/2012 8:30:49 PM PST · by SunkenCiv · 6 replies
    NASA ^ | December 04, 2012 | (see photo credit)
    Explanation: What's happening at the north pole of Saturn? A vortex of strange and complex swirling clouds. The center of this vortex was imaged in unprecedented detail last week by the robotic Cassini spacecraft orbiting Saturn. These clouds lie at the center of the unusual hexagonal cloud system that surrounds the north pole of Saturn. Saturn's north pole precessed into sunlight just a few years ago, with Cassini taking only infrared images of the shadowed region previously. The above image is raw and unprocessed and is being prepared for release in 2013. Several similar images of the region have recently...
  • Astronomy Picture of the Day -- A Quadruple Lunar Halo Over Spain

    12/02/2012 9:17:35 PM PST · by SunkenCiv · 7 replies
    NASA ^ | December 03, 2012 | (see photo credit)
    Explanation: Sometimes falling ice crystals make the atmosphere into a giant lens causing arcs and halos to appear around the Sun or Moon. This past Saturday night was just such a time near Madrid, Spain, where a winter sky displayed not only a bright Moon but as many as four rare lunar halos. The brightest object, near the top of the above image, is the Moon. Light from the Moon refracts through tumbling hexagonal ice crystals into a 22 degree halo seen surrounding the Moon. Elongating the 22 degree arc horizontally is a circumscribed halo caused by column ice crystals....
  • Astronomy Picture of the Day -- The Gegenschein Over Chile

    12/01/2012 9:56:19 PM PST · by SunkenCiv · 6 replies
    NASA ^ | December 02, 2012 | (see photo credit)
    Explanation: Is the night sky darkest in the direction opposite the Sun? No. In fact, a rarely discernable faint glow known as the gegenschein (German for "counter glow") can be seen 180 degrees around from the Sun in an extremely dark sky. The gegenschein is sunlight back-scattered off small interplanetary dust particles. These dust particles are millimeter sized splinters from asteroids and orbit in the ecliptic plane of the planets. Pictured above from 2008 October is one of the more spectacular pictures of the gegenschein yet taken. Here a deep exposure of an extremely dark sky over Paranal Observatory in...
  • Astronomy Picture of the Day -- Northern Mercury

    12/01/2012 10:10:52 AM PST · by SunkenCiv · 13 replies
    NASA ^ | December 01, 2012 | (see photo credit)
    Explanation: Innermost planet Mercurywould probably not be a good location for an interplanetary winter olympics. But new results based on data from the Mercury orbitingMESSENGER spacecraft indicate that it does have substantial water icein permanently shadowed regions within craters near its north pole. The possibility of ice on Mercury has been entertained for years, inspired by the discovery of radar bright, hence highly reflective, regions near the north pole. Highlighted in yellow in this map based on projected MESSENGER images, radar bright regions are seen to correspond with floors and walls of north polar impact craters. Farther from the pole...
  • Astronomy Picture of the Day -- Clouds in Cygnus

    11/30/2012 7:47:55 PM PST · by SunkenCiv · 5 replies
    NASA ^ | November 30, 2012 | (see photo credit)
    Explanation: Cosmic clouds of gas and dust drift across this magnificent mosaic covering a 12x12 degree field within the high flying constellation Cygnus. The collaborative skyscape, a combination of broad and narrow band image data presented in the Hubble palette, is anchored by bright, hot, supergiant star Deneb, below center near the left edge. Alpha star of Cygnus, Deneb, is the top of the Northern Cross asterism and is seen here next to the dark void known as the Northern Coal Sack. Below Deneb are the recognizable North America and Pelican nebulae (NGC 7000 and IC 5070). Another supergiant star,...
  • Astronomy Picture of the Day — Super Moon vs. Micro Moon

    11/30/2012 7:40:02 PM PST · by SunkenCiv · 8 replies
    NASA ^ | November 29, 2012 | (see photo credit)
    Explanation: Did you see the big, bright, beautiful Full Moon Wednesday night? That was actually a Micro Moon! On that night, the smallest Full Moon of 2012 reached its full phase only about 4 hours before apogee, the most distant point from Earth in the Moon's elliptical orbit. Of course, earlier this year on May 6, a Full Super Moon was near perigee, the closest point in its orbit. The relative apparent size of November 28's Micro Moon (right) is compared to the famous May 6 Super Moon in these two panels, matching telescopic images from Bucharest, Romania. The difference...
  • Astronomy Picture of the Day -- Jupiter and Io

    11/28/2012 6:28:42 PM PST · by SunkenCiv · 24 replies
    NASA ^ | November 28, 2012 | (see photo credit)
    Explanation: On December 3 (UT), Jupiter, the solar system's largest planet, will be at opposition, opposite the Sun in planet Earth's sky, shining brightly and rising as the Sun sets. That configuration results in Jupiter's almost annual closest approach to planet Earth. So, near opposition the gas giant offers earthbound telescopes stunning views of its stormy, banded atmosphere and large Galilean moons. For example, this sharp series was recorded on the night of November 16/17 from the island of Sardinia near Dolianova, Italy. North is up in the images that show off Jupiter's famous Great Red Spot, and planet girdling...
  • Astronomy Picture of the Day -- Bright Jupiter in Taurus

    11/27/2012 3:22:35 AM PST · by SunkenCiv · 4 replies
    NASA ^ | November 27, 2012 | (see photo credit)
    Explanation: That bright star you've recently noticed rising just after sunset isn't a star at all. It's Jupiter, the solar system's ruling gas giant. Bright Jupiter is nearing its December 3rd opposition when it will stand in Taurus, opposite the Sun in planet Earth's sky. Clearly outshining yellowish Aldebaran, alpha star of Taurus, Jupiter is centered in this skyview from November 14th, also featuring the Pleiades and Hyades star clusters, familiar celestial sights as the northern hemisphere winter approaches. Sliding your cursor over the image will label the scene and identify two other solar system worlds approaching their opposition in...
  • Astronomy Picture of the Day -- Wisps of the Veil Nebula

    11/26/2012 7:28:18 PM PST · by SunkenCiv · 9 replies
    NASA ^ | November 26, 2012 | (see photo credit)
    Explanation: Wisps like this are all that remain visible of a Milky Way star. About 9,000 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400...
  • Astronomy Picture of the Day -- Dark Sand Cascades on Mars

    11/26/2012 7:25:19 PM PST · by SunkenCiv · 23 replies
    NASA ^ | November 25, 2012 | (see photo credit)
    Explanation: They might look like trees on Mars, but they're not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The above image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks -- streaks that might appear at first...
  • Astronomy Picture of the Day -- NGC 1365: Majestic Spiral with Supernova

    11/24/2012 4:51:09 AM PST · by SunkenCiv · 16 replies
    NASA ^ | November 24, 2012 | (see photo credit)
    Explanation: Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the chemical constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax galaxy cluster. This sharp color image shows intense star forming regions at the ends of the bar and along the spiral arms, and details of dust lanes cutting across the galaxy's bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming...
  • Astronomy Picture of the Day -- The Pipe Nebula

    11/23/2012 12:44:51 AM PST · by SunkenCiv · 4 replies
    NASA ^ | November 23, 2012 | (see photo credit)
    Explanation: East of Antares, dark markings sprawl through crowded star fields toward the center of our Milky Way Galaxy. Cataloged in the early 20th century by astronomer E. E. Barnard, the obscuring interstellar dust clouds include B59, B72, B77 and B78, seen in silhouette against the starry background. Here, their combined shape suggests a pipe stem and bowl, and so the dark nebula's popular name is the Pipe Nebula. The deep and expansive view was represents nearly 24 hours of exposure time recorded in very dark skies of the Chilean Atacama desert. It covers a full 10 by 10 degree...
  • Astronomy Picture of the Day -- Night of the Long Leonid

    11/23/2012 12:40:23 AM PST · by SunkenCiv · 10 replies
    NASA ^ | November 22, 2012 | (see photo credit)
    Explanation: A cosmic grain of sand left the long and colorful trail across this all-sky view. Its grazing impact with planet Earth's atmosphere began at 71 kilometers per second. With the Milky Way stretching from horizon to horizon, the scene was captured on the night of November 17 from the astronomically popular high plateau at Champ du Feu in Alsace, France. Of course, the earthgrazer meteor belongs to this month's Leonid meteor shower, produced as our fair planet annually sweeps through dust from the tail of periodic Comet Tempel-Tuttle. The shower's radiant point in the constellation Leo is very close...
  • Astronomy Picture of the Day -- Diamond Ring and Shadow Bands

    11/21/2012 4:13:51 AM PST · by SunkenCiv · 2 replies
    NASA ^ | November 21, 2012 | (see photo credit)
    Explanation: As the total phase of last week's solar eclipse came to an end, sunlight streaming past the edge of the Moon created the fleeting appearance of a glistening diamond ring in the sky. And while most eclipse watchers did not consider clouds a welcome sight, a view through thin clouds north of Cairns in Queensland, Australia also revealed these remarkable flickering shadow bands. Projected onto the cloud layer, the bands are parallel to the sliver of emerging sunlight. Caused by turbulence in Earth's atmosphere refracting the sliver of sunlight, the narrow bands were captured in this brief, 1/1000th second...
  • Mars Mystery: What HAS Curiosity Discovered?

    11/20/2012 1:45:34 PM PST · by Red Badger · 90 replies
    Discovery.com ^ | Tue Nov 20, 2012 02:13 PM ET | Analysis by Ian O'Neill
    Science isn't something that just happens overnight. It takes many measurements, oodles of analysis, re-testing and re-analysis before any groundbreaking announcement can be made. So, on the surface of Mars, inside Gale Crater on a plain called Aeolis Palus, our tenacious six-wheeled Mars Science Laboratory (MSL) is doing cutting-edge laboratory work on an alien world and mission scientists are itching to announce a "historic" discovery. "This data is gonna be one for the history books. It's looking really good," John Grotzinger, lead scientist of the MSL mission, said in an interview with NPR. But what is he referring to and...
  • Lonely planet: Orphan world spotted in deep space

    11/20/2012 6:33:42 AM PST · by Red Badger · 18 replies
    Space Daily ^ | 14 NOV 2012 | by Staff Writers
    Astronomers on Wednesday reported they had detected a planet that had strayed from its star system and was wandering alone in deep space. Object CFBDSIR2149 is believed to be a cold, young world that for unknown reasons has pulled free of the gravitational pull of its mother star, the European Southern Observatory (ESO) said. It is not the first time that a "free-floating" planet has been found, but this one is the closest that has ever been spotted, at over 100 light years from Earth. Initial observations sketched the object as either a homeless planet or a tiny failed star...
  • Astronomy Picture of the Day -- A Halo Around the Moon

    11/20/2012 3:27:14 AM PST · by SunkenCiv · 20 replies
    NASA ^ | November 20, 2012 | (see photo credit)
    Explanation: Have you ever seen a halo around the Moon? This fairly common sight occurs when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Moon Halo. A similar Sun Halo may be visible during the day. The setting of the above picture is Athens San Sebastian, Greece. The distant planet Jupiter appears by chance...
  • Astronomy Picture of the Day -- Leonids Over Monument Valley

    11/19/2012 3:41:20 AM PST · by SunkenCiv · 5 replies
    NASA ^ | November 19, 2012 | (see photo credit)
    Explanation: What's happening in the sky over Monument Valley? A meteor shower. Over the past weekend the Leonid meteor shower has been peaking. The image -- actually a composite of six exposures of about 30 seconds each -- was taken in 2001, a year when there was a much more active Leonids shower. At that time, Earth was moving through a particularly dense swarm of sand-sized debris from Comet Tempel-Tuttle, so that meteor rates approached one visible streak per second. The meteors appear parallel because they all fall to Earth from the meteor shower radiant -- a point on the...
  • Astronomy Picture of the Day -- NGC 6357's Cathedral to Massive Stars

    11/18/2012 6:13:47 AM PST · by SunkenCiv · 13 replies
    NASA ^ | November 18, 2012 | (see photo credit)
    Explanation: How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, nearly making it the record holder. This star is the brightest object located just above the gas front in the above image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the...
  • Astronomy Picture of the Day -- Like a Diamond in the Sky

    11/16/2012 9:40:40 PM PST · by SunkenCiv · 11 replies
    NASA ^ | November 17, 2012 | (see photo credit)
    Explanation: A dark Sun hung over Queensland, Australia on Wednesday morning during a much anticipated total solar eclipse. Storm clouds threatened to spoil the view along the northern coast, but minutes before totality the clouds parted. Streaming past the Moon's edge, the last direct rays of sunlight produced a gorgeous diamond ring effect in this scene from Ellis Beach between Cairns and Port Douglas. Winking out in a moment, the diamond didn't last forever though. The area was plunged into darkness for nearly 2 minutes as the Moon's shadow swept off shore toward Australia's Great Barrier Reef and out into...
  • JPL Solar System Simulator

    11/16/2012 4:38:31 AM PST · by lbryce · 3 replies
    JPL ^ | Staff
    This is one of the most interesting,complex of the Solar System Simulators by JPL. It lists all the planets with every one of its moons, plus many numerous missions including the Voyager I and II. You can program the simulator to view every object from any location. There are lots of ways to configure it and you can spend hours playing around with all its features, Lots of fun for the desktop astronomer. The graphics are somewhat dated but are still very good at providing the thrill of viewing Titan from Saturn or any one planetary body to another.
  • Astronomy Picture of the Day -- Moon Shadow Sequence

    11/16/2012 3:17:24 AM PST · by SunkenCiv · 6 replies
    NASA ^ | November 16, 2012 | (see photo credit)
    Explanation: On the morning of November 14, the Moon's umbral shadow tracked across northern Australia before heading into the southern Pacific. Captured from a hilltop some 30 miles west of the outback town of Mount Carbine, Queensland, a series of exposures follows the progress of the total solar eclipse in this dramatic composite image. The sequence begins near the horizon. The Moon steadily encroaches on the on the reddened face of the Sun, rising as the eclipse progresses. At the total phase, lasting about 2 minutes for that location, an otherwise faint solar corona shimmers around the eclipsed disk. Recorded...
  • Astronomy Picture of the Day -- Solar Eclipse over Queensland

    11/15/2012 7:19:35 PM PST · by SunkenCiv · 5 replies
    NASA ^ | November 15, 2012 | (see photo credit)
    Explanation: This month's New Moon brought a total solar eclipse to parts of planet Earth on November 13 (UT). Most of the total eclipse track fell across the southern Pacific, but the Moon's dark umbral shadow began its journey in northern Australia on Wednesday morning, local time. From along the track, this telescopic snapshot captures the Moon's silhouette in skies over Queensland along the Mulligan highway west of Port Douglas. Almost completely covered, the Sun's disk is seen still surrounded by a hint of the faint solar corona. Planet-sized prominences stretch above the active Sun's edge. Sunlight streaming through gaps...
  • Astronomy Picture of the Day -- Our Story in One Minute

    11/14/2012 6:20:29 PM PST · by SunkenCiv · 18 replies
    NASA ^ | November 14, 2012 | (see photo credit)
    Explanation: Could you tell the story of human existence in a minute? This thrilling video culls together multiple teasing snippets in an attempt to do just that. And sets it to music. Briefly depicted, from start to finish, is an artistic animation of the Big Bang, a trip across the early universe, the formation of the Earth and Moon, the emergence of multi-celled life and plants, the rise of reptiles and dinosaurs, a devastating meteor strike, the rise of mammals and humans, and finally the rise of modern civilization. The minute movie ends with a flyover of the modern skyscraper...
  • Astronomy Picture of the Day -- A Solar Eclipse Quilt

    11/13/2012 3:34:35 AM PST · by SunkenCiv · 10 replies
    NASA ^ | November 13, 2012 | (see photo credit)
    Explanation: Some people are so inspired by solar eclipses that they quilt. Pictured above is a resulting textile from one such inspiration. The 38x38 inch quilt offers impressions of a total annular eclipse, when the Moon is too far from the Earth to cover the entire Sun, witnessed in Spain in October of 2005. Today, however, a full total solar eclipse will occur, although it will only be visible to eclipse chasers and those who live in a thin swath of Australia. For a few minutes, those near the center of the eclipse path will see the entire Sun blocked...
  • Astronomy Picture of the Day -- Meteor and Moonbow over Wallaman Falls

    11/12/2012 7:49:07 PM PST · by SunkenCiv · 9 replies
    NASA ^ | November 12, 2012 | (see photo credit)
    Explanation: Which feature takes your breath away first in this encompassing panorama of land and sky? The competition is strong with a waterfall, meteor, starfield, and even a moonbow all vying for attention. It is interesting to first note, though, what can't be seen -- a rising moon on the other side of the camera. The bright moon not only illuminated this beautiful landscape in Queensland, Australia last June, but also created the beautiful moonbow seen in front of Wallaman Falls. Just above the ridge in the above image is the horizontal streak of an airplane. Toward the top of...
  • Astronomy Picture of the Day -- Baily's Beads near Solar Eclipse Totality

    11/11/2012 4:47:17 AM PST · by SunkenCiv · 6 replies
    NASA ^ | November 11, 2012 | (see photo credit)
    Explanation: Just before the Sun blacks out, something strange occurs. As the Moon moves to completely cover the Sun in a total solar eclipse -- like the one set to occur over parts of Australia on Tuesday -- beads of bright sunlight stream around the edge of the Moon. This effect, known as Baily's beads, is named after Francis Baily who called attention to the phenomenon in 1836. Although, the number and brightness of Baily's beads used to be unpredictable, today the Moon is so well mapped that general features regarding Baily's beads are expected. When a single bead dominates,...
  • Astronomy Picture of the Day -- Polar Ring Galaxy NGC 660

    11/10/2012 9:57:08 AM PST · by SunkenCiv · 13 replies
    NASA ^ | November 10, 2012 | (see photo credit)
    Explanation: NGC 660 is featured in this cosmic snapshot, a sharp composite of broad and narrow band filter image data from the Gemini North telescope on Mauna Kea. Over 20 million light-years away and swimming within the boundaries of the constellation Pisces, NGC 660's peculiar appearance marks it as a polar ring galaxy. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk. The bizarre-looking configuration could have been caused by the chance capture of material from a passing galaxy by a...
  • Astronomy Picture of the Day -- Melotte 15 in the Heart

    11/10/2012 9:52:16 AM PST · by SunkenCiv · 8 replies
    NASA ^ | November 09, 2012 | (see photo credit)
    Explanation: Cosmic clouds seem to form fantastic shapes in the central regions of emission nebula IC 1805. Of course, the clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are toward the right in this colorful skyscape, along with dark dust clouds in silhouette against glowing atomic gas. A composite of narrow and broad band telescopic images, the view spans about 30 light-years and includes emission from hydrogen in green, sulfur in red, and oxygen in blue hues. Wider field images...
  • Astronomy Picture of the Day -- Arp 188 and the Tadpole's Tail

    11/10/2012 9:42:12 AM PST · by SunkenCiv · 8 replies
    NASA ^ | November 08, 2012 | (see photo credit)
    Explanation: In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from right to left in this view - and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal...
  • Visit Uwingu, name an exoplanet

    11/08/2012 1:44:57 PM PST · by Red Badger · 8 replies
    Phys.org ^ | 11-08-2012 | Staff
    Astronomers have now discovered over 1,000 planets orbiting other stars, and right now these exoplanets all have boring, license-plate-like names, such as HD85512 and GJ 436 instead of endearing, "real" planet names that might offer hints of what that world could be like. And recall the recent extrapolation of how many habitable planets might be in the Milky Way? A team using the ESO's HARP's spectrograph determined there might be upwards of 160 billion worlds out there for us to find, and perhaps eventually name. How might we come up with that many names? Uwingu, a startup company that is...
  • Astronomy Picture of the Day -- Superstorm Sandy From Formation to Landfall

    11/07/2012 3:24:19 AM PST · by SunkenCiv · 7 replies
    NASA ^ | November 07, 2012 | (see photo credit)
    Explanation: It was the largest hurricane ever recorded in the Atlantic Ocean. The cost of its devastation is still unknown. Pictured above is a movie of Superstorm Sandy taken by the Earth-orbiting GOES-13 satellite over eight days in late October as the hurricane formed, gained strength, advanced across the Caribbean, moved up the Atlantic Ocean along the US east coast, made an unusual turn west, made landfall in New Jersey, turned back to the north over Pennsylvania, and then broke up moving north-east over the northern US and Canada. Although Sandy's winds were high and dangerous, perhaps even more damaging...
  • Astronomy Picture of the Day -- Methone: Smooth Egg Moon of Saturn

    11/06/2012 1:46:47 AM PST · by SunkenCiv · 6 replies
    NASA ^ | November 06, 2012 | (see photo credit)
    Explanation: Why is this moon shaped like a smooth egg? The robotic Cassini spacecraft completed the first flyby ever of Saturn's small moon Methone in May and discovered that the moon has no obvious craters. Craters, usually caused by impacts, have been seen on every moon, asteroid, and comet nucleus ever imaged in detail -- until now. Even the Earth and Titan have craters. The smoothness and egg-like shape of the 3-kilometer diameter moon might be caused by Methone's surface being able to shift -- something that might occur were the moon coated by a deep pile of sub-visual rubble....
  • Astronomy Picture of the Day -- Saturn's Moon Dione in Slight Color

    11/05/2012 6:28:13 PM PST · by SunkenCiv · 4 replies
    NASA ^ | November 05, 2012 | (see photo credit)
    Explanation: Why does one half of Dione have more craters than the other? Start with the fact that Saturn's moon Dione has one side that always faces Saturn, and one side that always faces away. This is similar to Earth's Moon. This tidal locking means that one side of Dione always leads as the moon progresses in its orbit, while the other side always trails. Dione should therefore have undergone a significant number of impacts on its leading half. Strangely, the current leading half of Dione is less cratered than the trailing half. A leading explanation is that some crater-forming...
  • Astronomy Picture of the Day -- Lenticular Clouds Over Washington

    11/04/2012 3:37:09 AM PST · by SunkenCiv · 16 replies
    NASA ^ | November 04, 2012 | (see photo credit)
    Explanation: Are those UFOs near that mountain? No -- they are multilayered lenticular clouds. Moist air forced to flow upward around mountain tops can create lenticular clouds. Water droplets condense from moist air cooled below the dew point, and clouds are opaque groups of water droplets. Waves in the air that would normally be seen horizontally can then be seen vertically, by the different levels where clouds form. On some days the city of Seattle, Washington, USA, is treated to an unusual sky show when lenticular clouds form near Mt. Rainier, a large mountain that looms just under 100 kilometers...
  • Astronomy Picture of the Day -- Hunter's Moon over the Alps

    11/02/2012 9:16:50 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | November 03, 2012 | (see photo credit)
    Explanation: A Full Moonset can be a dramatic celestial sight, and Full Moons can have many names. Late October's Full Moon, the second Full Moon after the northern hemisphere autumnal equinox, has been traditionally called the Hunter's Moon. According to lore, the name is a fitting one because this Full Moon lights the night during a time for hunting in preparation for the coming winter months. In this scene, last week's Hunter's Moon shines with a rich yellow light, setting as dawn comes to the Italian Alps. Topping out at over 11,000 feet, the snowy peak known as Rochemelon glows,...
  • Astronomy Picture of the Day -- The Black Hole in the Milky Way

    11/02/2012 3:55:34 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | November 02, 2012 | (see photo credit)
    Explanation: At the center of our Milky Way Galaxy, a mere 27,000 light-years away, lies a black hole with 4 million times the mass of the Sun. Fondly known as Sagittarius A* (pronounced A-star), the Milky Way's black hole is fortunately mild-mannered compared to the central black holes in distant active galaxies, much more calmly consuming material around it. From time to time it does flare-up, though. A recent outburst lasting several hours is captured in this series of premier X-ray images from the orbiting Nuclear Spectroscopic Telescope Array (NuSTAR). Launched last June 13, NuSTAR is the first to provide...
  • Astronomy Picture of the Day -- Rigel and the Witch Head Nebula

    11/01/2012 5:33:22 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | November 01, 2012 | (see photo credit)
    Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. The suggestively shaped reflection nebula is associated with the bright star Rigel in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula spans about 50 light-years and is composed of interstellar dust grains reflecting Rigel's starlight. In this cosmic portrait, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's intense blue starlight but because the dust grains scatter blue light more efficiently than red....
  • Astronomy Picture of the Day -- VdB 152: A Ghost in Cepheus

    10/31/2012 2:52:49 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 31, 2012 | (see photo credit)
    Explanation: Described as a "dusty curtain" or "ghostly apparition", mysterious reflection nebula VdB 152 really is very faint. Far from your neighborhood on this Halloween Night, the cosmic phantom is nearly 1,400 light-years away. Also catalogued as Ced 201, it lies along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving parts of the nebula a characteristic blue color. Ultraviolet light from the star is also thought to cause a dim...
  • Astronomy Picture of the Day -- Planetary Nebula PK 164 +31.1

    10/30/2012 4:11:47 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 30, 2012 | (see photo credit)
    Explanation: Is this what will become of our Sun? Quite possibly. The bubble of expanding gas pictured above is the planetary nebula PK 164 +31.1, the remnants of the atmosphere of a Sun-like star expelled as its supply of fusion-able core hydrogen became depleted. Visible near the center of the nebula is what remains of the core itself -- a blue-hot white dwarf star. This particularly photogenic planetary nebula shows intricate shells of gas likely expelled at different times toward the end the star's demise, and whose structure is not fully understood. This deep image of PK 164 +31.1 from...
  • Astronomy Picture of the Day -- The Red Spider Planetary Nebula

    10/29/2012 12:33:23 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 29, 2012 | (see photo credit)
    Explanation: Oh what a tangled web a planetary nebula can weave. The Red Spider Planetary Nebula shows the complex structure that can result when a normal star ejects its outer gases and becomes a white dwarf star. Officially tagged NGC 6537, this two-lobed symmetric planetary nebula houses one of the hottest white dwarfs ever observed, probably as part of a binary star system. Internal winds emanating from the central stars, visible in the center, have been measured in excess of 1000 kilometers per second. These winds expand the nebula, flow along the nebula's walls, and cause waves of hot gas...
  • Astronomy Picture of the Day -- Phobos: Doomed Moon of Mars

    10/28/2012 11:59:25 AM PDT · by SunkenCiv · 54 replies
    NASA ^ | October 28, 2012 | (see photo credit)
    Explanation: This moon is doomed. Mars, the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos, whose names are derived from the Greek for Fear and Panic. These martian moons may well be captured asteroids originating in the main asteroid belt between Mars and Jupiter or perhaps from even more distant reaches of the Solar System. The larger moon, Phobos, is indeed seen to be a cratered, asteroid-like object in this stunning color image from the Mars Reconnaissance Orbiter, recorded at a resolution of about seven meters per pixel. But Phobos orbits so...
  • Astronomy Picture of the Day -- A Halo for NGC 6164

    10/27/2012 1:56:18 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 27, 2012 | (see photo credit)
    Explanation: Beautiful emission nebula NGC 6164 was created by a rare, hot, luminous O-type star, some 40 times as massive as the Sun. Seen at the center of the cosmic cloud, the star is a mere 3 to 4 million years old. In another three to four million years the massive star will end its life in a supernova explosion. Spanning around 4 light-years, the nebula itself has a bipolar symmetry. That makes it similar in appearance to more familiar planetary nebulae - the gaseous shrouds surrounding dying sun-like stars. Also like many planetary nebulae, NGC 6164 has been found...
  • Astronomy Picture of the Day -- Reflection Nebula vdB1

    10/26/2012 3:44:26 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 26, 2012 | (see photo credit)
    Explanation: Every book has a first page and every catalog a first entry. And so this lovely blue cosmic cloud begins the van den Bergh Catalog (vdB) of stars surrounded by reflection nebulae. Interstellar dust clouds reflecting the light of the nearby stars, the nebulae usually appear blue because scattering by the dust grains is more effective at shorter (bluer) wavelengths. The same type of scattering gives planet Earth its blue daytime skies. Van den Bergh's 1966 list contains a total of 158 entries more easily visible from the northern hemisphere, including bright Pleiades cluster stars and other popular targets...
  • Astronomy Picture of the Day -- The Medusa Nebula

    10/25/2012 3:46:19 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | October 25, 2012 | (see photo credit)
    Explanation: Braided, serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun, as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star...
  • Astronomy Picture of the Day -- NGC 206 and the Star Clouds of Andromeda

    10/24/2012 3:44:36 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 24, 2012 | (see photo credit)
    Explanation: The large stellar association cataloged as NGC 206 is nestled within the dusty arms of neighboring spiral galaxy Andromeda (M31), 2.5 million light-years distant. Seen near the center of this gorgeous close-up of the southwestern extent of Andromeda's disk, the bright, blue stars of NGC 206 indicate its youth. Its youngest massive stars are less than 10 million years old. Much larger than the clusters of young stars in the disk of our Milky Way galaxy known as open or galactic clusters, NGC 206 spans about 4,000 light-years. That's comparable in size to the giant stellar nurseries NGC 604...
  • New Images: Scientists Puzzled By Uranus Weather Patterns

    10/23/2012 9:39:04 AM PDT · by Red Badger · 29 replies
    www.redorbit.com ^ | 10-21-2012 | Staff
    New, exquisitely detailed, high-resolution images of Uranus show off its complex weather patterns and new features of the planet that scientists can’t explain yet. Uranus, the seventh planet from the Sun, is an ice giant composed mainly of frozen methane, water, ammonia and hydrocarbons. In 1986, Voyager 2 passed by Uranus and returned the iconic image that most associate with the planet. This image showed a smooth, blue-green featureless world. This newest image reveals something different, a world swept with intricate cloudy bands, much like Jupiter and Saturn. Uranus is at such a distance from Earth that most telescopes can’t...
  • Astronomy Picture of the Day -- Mammatus Clouds Over Saskatchewan

    10/23/2012 3:11:51 AM PDT · by SunkenCiv · 17 replies
    NASA ^ | October 23, 2012 | (see photo credit)
    Explanation: Normal cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pockets may occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. These mammatus clouds were photographed over Regina, Saskatchewan, Canada during the past summer....