Astronomy in English

The Turbulent Neighborhood of Eta Carina

2010-03-16T07:38:00.001+02:00

The Turbulent Neighborhood of Eta Carina

How do violent stars affect their surroundings? To help find out, astronomers pointed the Hubble Space Telescope to the regions surrounding Eta Carina, a star showing signs that it may explode sometime in the next million years. The nearby nebulosity, shown above, is home to streams of hot gas, pools of cool gas, knots of dark globules, and pillars of dense dusty interstellar matter likely forming young stars. The above image explores about three light-years, a region size intermediate to the Eta Carina cocoon, which spans only about one-half of a light year, and the Great Nebula in Carina, which spans over 300 light years. In April of 1843 Eta Car briefly became second only to Sirius as the brightest star in planet Earth's night sky, even though at a distance of about 7,500 light-years, it is about 800 times farther away.

A Late Leonid from a Sparse Shower

2010-02-28T10:33:00.001+02:00

A Late Leonid from a Sparse Shower

The 2003 Leonids Meteor Shower contained relatively few meteors. As expected and unlike the last few years, the Earth just did not pass through any dense particle streams left over by the Sun-orbiting Comet Tempel-Tuttle. Preliminary reports had the peak meteor rates only as high as about one relatively faint meteor a minute even from good locations at good times. Pictured above is one of the brighter Leonids of 2003, caught by one of the continuously operating night sky web cameras (CONCAMs) of the global Night Sky Live project. The fisheye image shows the night sky from horizon to horizon above Mauna Kea, Hawaii, USA. The image is annotated with several bright stars and planets. Note that this meteor, as do all Leonids, appears to emanate from the constellation Leo, labeled on the upper left. Although the peak of the Leonids this year was on November 19, this meteor flashed through the sky the next night.

IC 405 The Flaming Star Nebula

2010-01-21T22:06:00.001+02:00

IC 405 The Flaming Star Nebula

Rippling dust and gas lanes give the Flaming Star Nebula its name. The red and purple colors of the nebula are present in different regions and are created by different processes. The bright star AE Aurigae, visible toward the image right, is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, red light is frequently emitted.The purple region's color is a mix of this red light and blue light emitted by A Aurigae but reflected to us by surrounding dust.The two regions are referred to as emission nebula and reflection nebula, respectively. Pictured above, the Flaming Star Nebula, officially known as IC 405, lies about 1500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of Auriga.

A Superwind from the Cigar Galaxy

2010-01-20T23:16:00.000+02:00

A Superwind from the Cigar Galaxy

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 recently released photograph from the new Subaru Telescope highlights thespecific 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.

Moon AND Sun

2010-01-10T08:40:00.000+02:00

Moon AND Sun

This composite image was made from 22 separate picturesof the Moon and Sun all taken fro Chisamba, Zambia during thetotal phase of the 2001 June 21 solar eclipse.The multiple exposureswere digitally processed and combined tosimultaneously show a wealth of detail which no single cameraexposure or naked-eye observation could easily reveal.Most striking are the incredible flowing streamersof the Sun's outer atmosphere o solar corona, notoriously difficult to see except whe thenew Moon blocks the bright solar disk.Features on the darkened near sid of the Moon canalso be made out illuminatedby sunlight reflected fro afull Earth.A giant solar prominence seems to hangjust beyond the Moon's eastern (left) edge while about onediameter farther east of the eclipsed Sun is th relatively faint (4th magnitude)star 1 Geminorum.The still activ Sunwill be totally eclipsed by the Moon tomorrow,but the path of the total eclipse will mostly cross the relativelyinaccessible continen of Antarctica.

Sunset Moonlight

2010-01-09T20:45:00.001+02:00

Sunset Moonlight

November's lunar eclipsewas one of the shortest in recentyears and also one of the brightest --demonstrating that the Earth's shadow is not completely dark.The eclipsed Moon remained easily visible during totality,reflecting reddened light filtering on to its surfacefrom all the sunsetsand sunrises,as seen from th lunar perspective,around the edges of a silhouetted Earth.Hoping to view th celestial shadow play from theEarth's night side near Cologne, Germany, abou 400,000kilometers from the lunar surface amateur astronomerMarkus Strassfeld packed a digital cameraand telescope and drove about 10 kilometers outside the cityto escape the bright city lights.Fortunately, the sky cleared about an hour before theeclipse began and he was able to record this sharp image ofsunsets illuminating the totally eclipsed Moon.Young ray crater Tycho,about 85 kilometers across, stands out nearthe Moon's brighter southern edge.

Voyager at 90 AU

2010-01-06T21:53:00.001+02:00

Voyager at 90 AU

Launchedin 1977, Voyager 1 is now about 12 light-hoursor 90 astronomicalunits AU) from theSun, making this spacecraft humanity's mos distant ambassador to the cosmos.Well beyond the orbits of the outer planets, Voyager 1is believed to b enteringthe realm of deep spacenear the edge o theheliosphere, the region dominated bythe solar wind and magnetic field Causingsome debate, new results from instruments stilloperating have given indications that the spacecraftcould finally be encountering a fluctuatingboundary known as the solar wind's termination shock.Illustrated above, the bubble-shaped termination shock isproduced when th wind from the Sun slows dramaticallyand piles up as it runs in to the tenuous interstellar gas.Still farther out, beyon the heliopause,solar wind and interstellar gas begin to mix,while the heliosphere's motion through interstellar space create a bow shock, analogous toa boat moving through water.Estimates are that both Voyager 1 and 2 have enoughpower and fuel to operate until about the year 2020.The spacecraft continue to coast toward interstellar spaceat over 3 AU per year.

Light Can Twist as Well as Spin

2010-01-03T22:46:00.001+02:00

Light Can Twist as Well as Spin

Light is more complicated than we thought. When astronomers measure light, they are usually concerned with its direction, energy, and spin polarization (sometimes). Recently, however, it has been more broadly realized that photons can also have orbital angular momentum (OAM), an attribute classically analogous to the Earth orbiting the Sun as well as spinning on its axis. Pictured above, the wave-front of a photon with OAM is shown to be twisted, in contrast to the flat plane of zero OAM light Light with OAM might be used to increase the information content of communication or to discern specific types of astronomical sources.Passing through a common lens, light without OAM focuses to a point, whereas light with OAM focuses to a ring. Most light bouncing around the cosmos, however, is expected to have so little (or zero) OAM that the created ring is too small to measure. Even given other promising methods for measurement, exploiting OAM for astronomical discovery might be as much an issue of observational practicality as theoretical possibility. APOD Update: APOD mirror now on-line from Poland with archive in Polish.

Leonids Over Indian Cove

2010-01-02T09:47:00.001+02:00

Leonids Over Indian Cove

One year ago today an impressive meteor shower graced the skies of Earth. Pictured above from last year, at least six bright meteors are visible in only part of the sky above Indian Cove campground in California, USA, during a four-minute exposure. The 2002 Leonids packed a double punch with planet Earth plunging through two dense clouds of meteroids, dusty debris left by the passage of Comet Tempel-Tuttle. This year, unfortunately, the main peak of the Leonids Meteor Shower is not expected to be so impressive, with the Earth passing though parts of meteoroid clouds predicted to be much less dense. The main peak of the 2003 Leonids is predicted for tomorrow where some locations might see a bright meteor every minute.

Canis Major Dwarf A New Closest Galaxy

2009-12-25T22:40:00.001+02:00

Canis Major Dwarf A New Closest Galaxy

What is the closest galaxy to the Milky Way? The new answer to this old question is the Canis Major dwarf galaxy. For many years astronomers thought the Large Magellan Cloud (LMC) was closest, but its title was supplanted in 1994 by the Sagittarius dwarf galaxy. Recent measurements indicate that the Canis Major dwarf is only 42,000 light years from the Galactic center, about three quarters of the distance to the Sagittarius dwarf and a quarter of the distance to the LMC. The discovery was made in data from the 2MASS-sky survey, where infrared light allows a better view through our optically opaque Galactic plane. The labeled illustration above shows the location of the newly discovered Canis Major dwarf and its associated tidal stream of material in relation to our Milky Way Galaxy. The Canis Major dwarf and other satellite galaxies are slowly being gravitationally ripped apart as they travel around and through our Galaxy.

Leonids from Leo

2009-12-20T15:47:00.001+02:00

Leonids from Leo

Is Leo leaking? Leo, the famous sky constellation visible on the left of the above all-sky photograph, appears to be the source of all the meteors seen in 1998's Leonids Meteor Shower. That Leonids point back to Leo is not a surprise - it is the reason that this November meteor shower is called the Leonids. Sand-sized debris expelled from Comet Tempel-Tuttle follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation Leo. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Leo. Over 150 meteors can be seen in the above four-hour effort. The Leonids Meteor Shower of 2003 is expected to have two peaks,the first three days ago and the second a long-duration peak covering much of November 19. Although visible meteor rates might approach one per minute, they are predicted to be much less than in the previous few years.

LL Orionis When Cosmic Winds Collide

2009-12-17T20:49:00.001+02:00

LL Orionis When Cosmic Winds Collide

This arcing, graceful structure is actually abow shock about half alight-year across, created as the wind from young star LL Orioniscollides with th Orion Nebula flow.Adrift in Orion' stellar nurseryand still in its formative years,variable star LL Orionis produces a wind moreenergetic tha the wind from our ownmiddle-aged sun.As the fast stellar wind runs into slow moving gas a shock front isformed, analogous to th bowwave of a boat moving through water ora plane traveling at supersonic speed.The slower gas is flowing away from the Orion Nebula's hot central starcluster, th Trapezium, located off the lower right hand edgeof the picture.In threedimensions,LL Ori's wrap-around shock front is shaped like abowl that appears brightest when viewed along the "bottom" edge The complexstellar nursery in Orion shows a myriad of simila fluid shapes associated wit star formation, includingthe bow shock surrounding a faint star at the upper right.Part o a mosaic covering the Great Nebulain Orion, this composite color image was recordedin 1995 by the Hubble Space Telescope.

Jupiter Portrait

2009-12-13T10:05:00.001+02:00

Jupiter Portrait

Every day is a cloudy da onJupiter, th SolarSystem's reigning gas giant.And swirlin cloud tops are all you see inthis stunningly detailedtrue color image, a portion of a large digita mosaic portrait of Jupiter recordedfrom the Cassini spacecraft during it Jovianflyby in December 2000.The smallest features visible are about 60 kilometers across.Jupiter's composition is dominated by hydrogen an the clouds containhydrogen compounds like ammonia, hydrogen sulfide, and even water.A truly giant planet Jupiter's diameter is over 11 timesthe diameter of Earth and the smallest storms visible inthe Cassini Jupiter portrait are similar in size to largeterrestrial hurricanes Nowtraveling beyond Jupiter, th Cassini spacecraft is scheduledto reach the Saturnian system in July of 2004.

Aurora Oklahoma

2009-12-08T21:19:00.001+02:00

Aurora Oklahoma

Nestled in the central US, the state of Oklahomais noted for it gorgeous prairieskies and wide-open spaces,but not for frequent visitations o thenorthern lights.Still, following the intens solar activity late lastmonth, aurora did come sweeping down the Oklahoma plains an skywatcherDave Ewoldt managed to catch up withthis photogenic apparition 40 miles northwest ofOklahoma City at about 3am CST o October 29.Anticipatin aurora sightings, Ewoldthad spent the eveningphotographing nighttimeviews of small towns in the area whilekeeping an eye toward the north He reports,"I was just about ready to call it a night when theshow started. When it did, it was like someone turned on a lightswitch.I wish it would have lasted longer... [it] seemed like it wascompletely done in about 25 minutes."Watery reflections of the colorful show highlight the foregroundin the stunning image while stars of the Big Dipper and the northernsky shine behind the dazzlin Oklahomaauroral display. Skywatchers' note: First of tw Leonid meteor shower peaks tonight.

Mars Then and Now

2009-11-29T16:47:00.001+02:00

Mars Then and Now

Does Mars have canals? A hot debate topic of the late 1800s, several prominent astronomers including Percival Lowell not only claimed to see an extensive system of long straight canals on Mars, but used them to indicate that intelligent life exists there. The relatively close opposition of 1894 was used to make drawings like the one digitally re-scaled on the above left. The above map was originally prepared by Eugene Antoniadi and redrawnby Lowell Hess for the book Exploring Mars, by Roy A. Gallant.In more modern times, the latest Mars opposition has allowed the Hubble Space Telescope to capture a picture of similar orientation. Comparison of the two images shows that large features were impressively recorded, but that an extensive system of long and straight canals just does not exist. Satellites orbiting Mars have now shown conclusively that the red planet does indeed have surface features similar to canals, but that these are usually smaller, curved, and less extensive than that previously claimed. Real canyon systems like Noctis Labyrinthus are most likely cracks caused by surface stress.

Eclipsed Moonlight from Connelly s Springs

2009-11-28T11:44:00.001+02:00

Eclipsed Moonlight from Connelly s Springs

Happily, skiesover Connelly's Springs, North Carolina, USAwere not mostly cloudy, as forecast, on the evening of November 8.In fact they were mostly clear early on, allowing photographerDavid Cortner to record the evening' scheduledcelestial entertainment, total lunar eclipse.Cortner took telescopic pictures of the Moon everyeight minutes as it entered partial eclipsearound 6:30pm EST and progressed throughthe reddis totaleclipse phase while rising higher in the sky.Near the end of the eclipse he also recorded a wide-angle viewin a long exposure, bringing out thethickening clouds and a landscape silhouetted by still partiall eclipsed moonlight.Later, the telescopic views were carefully combined along th Moon's trail through thewide-angle image to creat this dramatic compositeeclipse sequence.

An Intermediate Polar Binary System

2009-11-26T18:42:00.001+02:00

An Intermediate Polar Binary System

How can two stars create such a strange and intricate structure? Most stars are members of multiple-star systems. Some stars are members of close binary systems where material from one star swirls around the other in an accretion disk. Only a handful of stars, however, are members of an intermediate polar, a system featuring a white dwarf star with a magnetic field that significantly pushes out the inner accretion disk, only allowing material to fall down its magnetic poles. Shown above is an artist's depiction of an intermediate polar system, also known as a DQ Hercules system. The foreground white dwarf is so close to the normal star that it strips away its outer atmosphere. As the white dwarf spins, the columns of infalling gas rotate with it. The name intermediate polar derives from observations of emitted light polarized at a level intermediate to non-disk binary systems known as polars. Intermediate polars are a type of cataclysmic variable star system.

Apollo 17 Lunarscape A Magnificent Desolation

2009-11-23T19:51:00.001+02:00

Apollo 17 Lunarscape A Magnificent Desolation

Buzz Aldrin, Apollo 11 Lunar Module pilot and th second human to walk onthe Moon, described the lunar landscape as "a magnificent desolation".Dramatic pictures fromthe Apollo missionsto the lunar surfacetestify to this apt turn of phrase.Near the Apollo 17 landing site,Family Mountain (center background) and the edge of South Massif (left) fram the lunarscape in this photo o astronaut Harrison Schmittworking alongsid the lunar roving vehicle.Schmitt and fello astronaut Eugene Cernan were th lastto walk on this magnificent desolation.

Eclipsed Moon in Infrared

2009-11-20T23:29:00.001+02:00

Eclipsed Moon in Infrared

The total lunar eclipse of September 1996disappointed many observers in North America whowere cursed with cloudy skies.However, th MidcourseSpace Experiment (MSX) satellite hada spectacular view from Earth orbit an SPIRIT III,an on board infrared telescope, was used torepeatedly image the moo during the eclipse.Above is one ofthe images taken during the 70 minute totality, the Moon completel immersed inthe Earth's shadow.Infrared ligh has wavelengthslonger than visible light - humans can not see it but feel it as heat.The bright spots correspond to the warm areas on thelunar surface, dark areas are cooler.The brightest spot below and left of center is th crater Tycho,the dark region at the upper right i the Mare Crisium.The series of SPIRIT III images allow the determination of coolingrates for geologically different areas, exploring the physical propertie of the Moon's surface.

November's Lunar Eclipse

2009-11-15T00:30:00.001+02:00

November's Lunar Eclipse

The Moon slides through the Earth's shadowthis Saturday night / Sunday morning (November 8/9) givingskygazers in the Americas, Europe,Africa, and western Asia a chance t enjoy a total lunar eclipse.A lunar eclipses go,this will be a brief onethough, with the total phase lasting only about 25 minutes.The orientation and relative size of th Earth's shadowand the Moon's trajectory are illustrated in this thoughtfulanimation showing the full Moon moving up from the lower right,entering the penumbra or outer portion of the shadow region,and then passing well below the center of the darker inner shadow regionor umbra.The tota eclipse phase beginsat 1:06 Universal Time, November 9(8:06pm EST Nov. 8 whenthe Moon is completely within the umbra.While the off-center passage guarantees a short total phase, italso makes it likely that this November's eclipsed Moon will bedramatically visible and colorfulwith a brighter rim along thesouthern edge.

Flare Well AR 10486

2009-11-09T21:12:00.001+02:00

Flare Well AR 10486

Almost out of view fro our fair planet,rotating around theSun's western edge, giant sunspot regio AR 10486lashed outwith another intense solar flare followed bya larg coronalmass ejection (CME) on Tuesday, November 4that about 1950 Universal Time.The flare itself is seen here at the lower right in an extremeultraviolet image from th sun-staring SOHO spacecraft's EITcamera.Saturating the EIT camera pixels and detectors onother satellites, this giant X-classflare was among themost powerful ever recorde sincethe 1970s, the third such historicblast from AR 10486 within the last two weeks.While energetic particle radiation from the flare did causesubstantial radio interference, the associated CME is notexpected to trigger extremely widespread aurorae as it glances offthe magnetosphere, unlike th direct hits from last week's CMEs.Say farewell to the mighty AR 10486, for now.For the next two weeks, the sunspot region will be on the Sun' far side.

The Lynx Arc

2009-11-08T10:42:00.000+02:00

The Lynx Arc

While chasing the spectrum of a mysterious arc in a cluster ofgalaxies within the obscure northerl constellationLynx, astronomers havestumbled upon the most massive and distant star-forming regio ever discovered.The notably red "Lynx arc" lies right of center i thiscolor image of the galaxy cluster, a composite ofHubble Space Telescope and ground-based data.While the galaxy cluster lies about 5 billionlight-years distant spectroscopic studiesshow that the arc itself is actually a distortedimage of an even more distant but enormous star-forming region.The image is formed as the closer galaxy cluster' gravitybends lightlike a magnifying lens, an effect explained by Einstein'stheory of gravity In fact, the monster star-forming region is nearly12 billio light-years awayand about a million times brighter than themore familiar stellar nursery, th Orion Nebula.Estimates are that the star-forming region seen as theLynx arc contains about a million massive, hot stars, comparedto the four stars which power theOrion Nebula's glow. Stars within the Lynx arc are more than twice as hotas the Orion Nebula's central starsand were formed whenthe Universe was a mere 2 billion years old.Still, astronomers believe that th first stars wereformed at even earlier times.

Aurora Over Edmonton

2009-11-08T08:45:00.000+02:00

Aurora Over Edmonton

Northern and southern locales saw many a beautiful aurora over the last week, as particles from severa large solar flares impacted the Earth. Many reported unusually red auroras, although colors across the spectrum were also seen. Power grids and orbiting satellites braced for the onslaught, but little lasting damage was reported. Pictured above, the Clover Bar Power Plant was photographed from the banks of the North Saskatchewan River in Edmonton, Alberta Canada. A small pond in the foreground reflects predominantly green aurora light far in the distance. Two days ago, again unexpectedly, another large solar flare occurred from sunspot group 10486, the site ofother recent major flares. This unusually active solar region is now rotating to the far side of the Sun.

Spiral Galaxy NGC 3982 Before Supernova

2009-11-06T22:27:00.001+02:00

Spiral Galaxy NGC 3982 Before Supernova

What do stars look like just before they explode? To find out, astronomers are taking detailed images of nearby galaxies now, before any supernova is visible. Hopefully, a star in one of the hundreds of high resolution galaxy images will explode in the coming years. If so, archival images like that taken above by the Hubble Space Telescope can be inspected to find what the star looked like originally. This information is likely important for better understanding of how and why supernovas occur, as well as why some supernovas appear brighter than others. Pictured above, beautiful spiral galaxy NGC 3982 displays numerous spiral arms filled with bright stars, blue star clusters, and dark dust lanes. NGC 3982, which spans about 30,000 light years, lies about 60 million light years from Earth and can be seen with a small telescope toward the constellation of Ursa Major.

A Giant Starspot on HD 12545

2009-10-28T21:03:00.003+02:00

A Giant Starspot on HD 12545

What could cause a star to have such a large spot? Our Sun itself frequently has sunspots, relatively cool dark magnetic depressions that move across its surface. HD 12545, however, exhibits the largest starspots yet observed. Doppler imaging - the use of slight changes in color caused by the rotation of the star - was used to create this false-color image. The vertical bar on the right gives a temperature scale i kelvins.This giant, binary, RS CVn star, also known as XX Trianguli, is visible with binoculars in the constellation of Triangulum. The starspot is thought to be caused by large magnetic fields that inhibit hot matter from flowing to the surface.

Halo of the Cat's Eye

2009-10-28T21:03:00.001+02:00

Halo of the Cat's Eye

The Cat's Eye Nebula(NGC 6543) is one of the best known planetarynebulae in the sky.Its haunting symmetries are seen in the very central regionof this stunning false-color picture, processed to reveal theenormous but extremely faint halo of gaseous material, over threelight-years across, which surrounds the brighter, familiar planetary nebula.Made with data from th Nordic Optical Telescopein the Canary Islands, the composite pictureshows emission fromnitrogen atoms as red and oxygen atoms as green and blue shades Planetarynebulae have long been appreciated as a final phas in the life of a sun-like star.Only much more recently however, have some planetaries bee found to have haloslike this one, likely formed of material shrugged off duringearlier active episodes in the star's evolution.While the planetarynebula phase is thought to last for around 10,000 years,astronomers estimate the age of the outer filamentary portionsof this halo to be 50,000 to 90,000 years.

A Dark and Stormy Night

2009-10-27T00:21:00.001+02:00

A Dark and Stormy Night

It was a dark and stormy night.But on August 29th the red planet Mars, near it closestapproachto Earth in almost 60,000 years, shone brightly in the sky againsta background of stars in th constellation Aquarius.In the foreground o thisscary view, huge thunder clouds arelit by lightningstrokes from within Mars,of course, has nothing to do with storms on Earth, thoughboth have the power to excite th imagination and wonde ofEarthdwellers.And whoknows wha luminoussights you might see if you go out tonight?Have a safe and Happy Halloween!

Aurora in Colorado Skies

2009-10-25T00:12:00.000+03:00

Aurora in Colorado Skies

Vividauroral displayswere triggered by a cloud o high energyparticles and magnetic fields from the Sun that collided with plane Earth'smagnetosphereyesterday, October 29, at about 06:3 Universal Time.The collision was anticipated, following a intensesolar flareand coronal mass ejection detected on October 28, and manyanxious skywatchers were rewarded with an enjoyable light show.While aurorae don't normall haunt skies in the southern UnitedStates, they were reporte from locations in Missouri, Texas,New Mexico, and California in the early morning hours.Near Yampa, Colorado astronomer Jimmy Westlake also spentearly yesterday morning enjoying the storm space weather.He was impressed by thi colorful apparition ofthe northern lights -- produced byoxygen and nitrogen atoms excited by collisions withenergetic particles from the magnetosphere andreturning to lower energy states,at altitudes of 100 kilometers or more.Brighter stars shine through the extreme high-altitudeglow which shows much lower cloudsand the distant horizon in silhouette.

A Powerful Solar Flare

2009-10-20T20:50:00.001+03:00

A Powerful Solar Flare

Yesterday, our Sun produced one of the most powerful solar flares in recorded history. Seen across the electromagnetic spectrum, the Sun briefly became over 100 times brighter in X-rays than normal. Over the next few days, as energetic particles emitted from these regions strike the Earth, satellite communications might be affected and auroras might develop. The flare and resulting CME, emitted from giant sunspot group 10486, was captured above as it happened by the by the LASCO instrument aboard the Sun-orbiting SOHO satellite.The disk of the Sun is covered to accentuate surrounding areas. The time-lapse movie shows the tremendous explosion in frames separated in real time by about 30 minutes each. The frames appear progressively noisier as protons from the flare begin to strike the detector. The SOHO satellite has been put in a temporary safe mode to avoid damage from the solar particle storm.

The SDSS 3D Universe Map

2009-10-18T12:39:00.001+03:00

The SDSS 3D Universe Map

The latest map of the cosmos again indicates that dark matter and dark energy dominate our universe. The Sloan Digital Sky Survey (SDSS) is on its way to measuring the distances to over one million galaxies. Galaxies first identified on 2D images, like the one shown above on the right, have their distances measured to create the 3D map. The SDSS currently reports 3D information for over 200,000 galaxies, now rivaling the 3D galaxy-count of the Two-Degree Field sky map. The latest SDSS map, shown above on the left, could only show the galaxy distribution it does if the universe was composed and evolved a certain way. After trying to match many candidate universes to it, the Cinderella universe that best fits the above map has 5% atoms, 25% dark matter, and 70% dark energy. Such a universe was previously postulated because its rapid recent expansion can explain why distant supernovas are so dim, and its early evolution can explain the spot distribution on the very distant cosmic microwave background.

Large Sunspot Groups 10484 and 10486

2009-10-10T14:18:00.001+03:00

Large Sunspot Groups 10484 and 10486

Two unusually large sunspot groups are now crossing the face of the Sun. Each group, roughly the size of Jupiter, is unusual not only for its size but because it is appearing over three years after solar maximum, the peak of solar surface activity. Sunspot group 10484 appears near the image center, while sunspot group 10486 is just coming over the left limb of the Sun. The active region associated with Sunspot 484 (the shorter nickname) has already jettisoned a large coronal mass ejection (CME) of particles out into the Solar System. When striking Earth, radiation of this sort has the power to interrupt normal satellite operations while simultaneously providing beautiful auroras. Rotating with the Sun, sunspots 484 and 486 will take about 30 days to make one complete circle, slowly evolving in size and shape during this time. After using extreme care never to look directly at the Sun, the above image was created by holding a digital camera up to a small telescope.

M16 Stars from Eagles EGGs

2009-10-01T22:30:00.000+03:00

M16 Stars from Eagles EGGs

Newborn stars are forming in the Eagle Nebula. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away.

Islands in the Photosphere

2009-09-26T23:41:00.007+03:00

Islands in the Photosphere

Awash in a sea o plasmaand anchored i magneticfields, sunspots are planet-sized, dark islands i thesolar photosphere, the bright surface of the Sun.Before the enlightened(!) age of cameras solar observerscreated detaile drawingsof sunspots as they changed an progressed across thevisible solar disk.But contemporary observersalso regularly use this time-honored methodof monitoring sunspots.In this sketch from March 6th 2001 astronomerGunther Groenez has faithfullyrecorded the intriguing shapesand shades of major visible sunspot groupsand labeled them according to their NOA active region number.Solar north is up and east to the right.Groenez' technical equipment includes H and 2H pencil leads for thesunspot umbra (dark) and penumbra (light) areas respectively.Want to draw sunspots too Now'syour chance as two large sunspot groups ar presently making their wayacross the solar disk.Activity associated with these large sunspots may trigge aurorain the coming days.

Mars Moons

2009-09-26T23:41:00.005+03:00

Mars Moons

APOD: 2003 October 24 - Mars Moons <div class="blogger-post-footer"></div> </article> <article> <h1>Cygnus Nebulosities</h1> <p>2009-09-26T23:41:00.003+03:00</p> Cygnus Nebulosities<br><br><br><br><title> APOD: 2003 October 23 - Cygnus Nebulosities <div class="blogger-post-footer"></div> </article> <article> <h1>The Heart and Soul Nebulas</h1> <p>2009-09-26T23:41:00.001+03:00</p> The Heart and Soul Nebulas<br><br><br><br>Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible above on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible above in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focussed on how massive stars form and how they affect their environment. <div class="blogger-post-footer"></div> </article> <article> <h1>The Belt of Venus over the Valley of the Moon</h1> <p>2009-09-20T22:15:00.001+03:00</p> The Belt of Venus over the Valley of the Moon<br><br><br><br>Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink. Called the Belt of Venus, this off-color band between the dark eclipsed sky and the blue sky can be seen in nearly every direction including that opposite the Sun. Straight above, blue sky is normal sunlight reflecting off the atmosphere. In the Belt of Venus, however, the atmosphere reflects light from the setting (or rising) Sun which appears more red. The Belt of Venus can be seen from any location with a clear horizon. Pictured above, the Belt of Venus was photographed above morning fog in the Valley of the Moon, a famous wine-producing region in northern California, USA.The belt is frequently caught by accident in other photographs. <div class="blogger-post-footer"></div> </article> <article> <h1>Neptune and Triton from Palomar</h1> <p>2009-09-15T00:10:00.001+03:00</p> Neptune and Triton from Palomar<br><br><br><br>How's the weather on Neptune? Tracking major weather patterns on the Solar System's outermost gas giant can help in the understanding of global weather patterns here on Earth. Each summer for the past five years, Neptune has been imaged and major weather patterns studied. The latest picture, taken on September 15, is shown above in false color. Visible in pink near Neptune's lower right is a new storm dubbed Annabelle that is several times larger than her terrestrial sister Isabel, a concurrent storm system that occurred here on Earth. Although Isabel lasted a few weeks, no one knows how long Annabelle will endure. On the upper right is Neptune's largest moon Triton, an unusual moon that sports volcanoes that spew ice. <div class="blogger-post-footer"></div> </article> <article> <h1>An Unusual Globule in IC 1396</h1> <p>2009-09-06T17:53:00.000+03:00</p> An Unusual Globule in IC 1396<br><br><br><br>Is there a monster in IC 1396? Known to some as the Elephant's Trunk Nebula, parts of gas and dust clouds of this star formation region may appear to take on foreboding forms, some nearly human. The only real monster here, however, is a bright young star too far from Earth to hurt us. Energetic light from this star is eating away the dust of the dark cometary globule near the top of the above image. Jets and winds of particles emitted from this star are also pushing away ambient gas and dust. Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a much larger region on the sky than shown here, with an apparent width of more than 10 full moons. <div class="blogger-post-footer"></div> </article> <article> <h1>The Last Moon Shot</h1> <p>2009-09-06T00:34:00.001+03:00</p> The Last Moon Shot<br><br><br><br>In 1865 JulesVerne predicted the invention of a space capsule thatcould carry people.In his science fiction stor "Fromthe Earth to the Moon", he outlined his vision ofa cannon in Florida so powerful that it could shoot "Projectile-Vehicle" carrying three adventurer to the Moon.Over 100 years later NASA,guided by Wernher Von Braun's vision, produced the Saturn V rocket.From spaceport in Florida,this rocket turned Verne's fictio into fact,launching 9 Apollo Lunar missions and allowing 12 astronaut towalk on the Moon Pictured isthe last moon shot Apollo 17, awaiting itsDecember 1972 night launch.Spotlights play on the rocket and launch padat dusk.Humans have no walked on on the lunar surface since. <div class="blogger-post-footer"></div> </article> <article> <h1>Astronomy Quilt of the Week</h1> <p>2009-08-30T09:20:00.000+03:00</p> Astronomy Quilt of the Week<br><br><br><br>Demonstrating her mastery of traditionalastronomical imaging techniqu quilter andastronomy enthusiast Judy Rosshas produced this spectacular composition of "AstronomyQuilt Piece of the Week".Her year-long effort resulted in an arrangement for asix by seven foot quilt consistingof 52 individual pieces(11 inches by 8 inches), one for each week,which she reports were inspired by her steady diet o APOD's daily offerings.Some of the pieces are based on actual pictures, such as theHubble Space Telescope's view of planet formin AB Aurigae or Bill Keel's image of thenearby Pinwheel Galaxy.Others, with titles likethe BlueCarpet Nebula an DuckContemplates Black Hole, are from her own creative imaginings. <div class="blogger-post-footer"></div> </article> <article> <h1>NGC 6888 X-Rays in the Wind</h1> <p>2009-08-25T18:59:00.000+03:00</p> NGC 6888 X-Rays in the Wind<br><br><br><br>NGC 6888, also known a the Crescent Nebula, isa cosmic bubble of interstellar gas about 25 light-years across.Created bywinds from the bright, massive star seen near the centerof this composite image, theshocked filaments of gas glowing at opticalwavelengths are represented in green and yellowish hues X-rayimage data from a portion of the nebula viewed bythe Chandra Observatory is overlaid in blue.Such isolate stellar windbubbles are not usually seen toproduc energetic x-rays, which requireheating gas to a million degrees celsius.Still, NGC 6888 seems to have accomplished thisas slow moving winds from the central star's initial transitionto a red supergiantwere overtaken and rammed by fasterwinds driven by the intense radiation from the star'sexposed inner layers Burning fuelat a prodigious rate and near the endof its stellar life, NGC 6888's central starshould ultimately go out with a bang, creating a supernovaexplosion in 100,000 years or so.NGC 6888 is about 5,000 light-years close, toward the constellatio Cygnus. <div class="blogger-post-footer"></div> </article> <article> <h1>Space Rock SQ222 Noticed After Pass</h1> <p>2009-08-23T22:43:00.000+03:00</p> Space Rock SQ222 Noticed After Pass<br><br><br><br>Why didn't we see it? An undetected asteroid zipped past the Earth undetected last month in the closest near miss yet recorded -- within a quarter of the distance to the Moon. Such a close call is actually quite common -- what was new was that we did see it, although the detection occurred hours after it happened.In fact, a rock this size strikes the Earth roughly once a year and smaller rocks strike the Earth daily. The global danger from the bus-sized space rock was minimal Robert Cash of Minor Planet Research Inc. discovered asteroid 2003 SQ222 in data from the sky-scanning Lowell Observatory Near Earth Object Search (LONEOS) Pictured above is the discovery image sequence of SQ222, shown stretched vertically to be more easily viewable Objects like SQ222 are hard to detect because they are so faint and move so fast. An ability to scan the sky to detect, catalog, and analyze such objects has been increasing notably in recent years. <div class="blogger-post-footer"></div> </article> <article> <h1>Iridescent Clouds Over Aiguille de la Tsa</h1> <p>2009-08-16T08:57:00.001+03:00</p> Iridescent Clouds Over Aiguille de la Tsa<br><br><br><br>Before the sun rose over the mountains,iridescent colors danced across the sky. The unexpected light show was caused by a batch of iridescentclouds, and captured on film in early September in Arolla, Wallis, Switzerland. The peak in the foreground of the above image is Aiguillede la Tsa. Iridescent clouds contain patches of waterdroplets of nearly identical size that can therefore diffract sunlight in a nearly uniform manner. Different colors will be deflected by different amounts and so come to the observer from slightly different directions. Iridescent clouds are best seen outside the glare of the direct Sun although they can occasionally be seen to encircle the Sun. <div class="blogger-post-footer"></div> </article> <article> <h1>Pelican Nebula Ionization Front</h1> <p>2009-08-02T12:01:00.001+03:00</p> Pelican Nebula Ionization Front<br><br><br><br>What's happening to the Pelican Nebula? The light from young energetic stars is slowly transforming the Pelican's cold gas to hot gas, with the advancing boundary between the two known as an ionization front. Most of these bright stars lie off the top of the image, but part of the bright ionization front crosses on the upper right.Particularly dense and intricate filaments of cold gas are visible along the front. Millions of years from now this nebula might no longer be known as the Pelican, as the balance and placement of stars and gas will leave something that appears completely different. The above image was taken with the Mayall 4-meter telescope at Kitt Peak National Observatory in Arizona, USA. The large circular artifact below the image center is not real.The nebula, also known as IC 5070, spans about 30 light years and lies about 1800 light years away toward the constellation of Cygnus. <div class="blogger-post-footer"></div> </article> <article> <h1>The Coma Cluster of Galaxies</h1> <p>2009-07-26T00:21:00.001+03:00</p> The Coma Cluster of Galaxies<br><br><br><br>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 Milky Way Galaxy does. Although nearby when compared to most other 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. <div class="blogger-post-footer"></div> </article> <article> <h1>Moonrise Over Seattle</h1> <p>2009-07-19T12:54:00.001+03:00</p> Moonrise Over Seattle<br><br><br><br>Is the Moon larger when near the horizon? No -- as shown above, the Moon appears to be very nearly the same size no matter its location on the sky. Oddly, the cause or causes for the common MoonIllusion are still being debated.Two leading explanations both hinge on the illusionthat foreground objects make a horizon Moon seem farther in the distance. The historically mostpopular explanation then holds that the mind interprets more distant objects as wider, while a morerecent explanation adds that the distance illusion may actually make the eye focus differently. Either way, the angulardiameter of the Moon is always about 0.5 degrees. In the above time-lapse sequence taken near the end of 2001, the Moon was briefly re-imaged every 2.5 minutes, with the last exposure of longer duration to bring up a magnificent panorama of the city of Seattle. <div class="blogger-post-footer"></div> </article> <article> <h1>Peculiar Arp 295</h1> <p>2009-07-18T00:31:00.001+03:00</p> Peculiar Arp 295<br><br><br><br>A spectacular bridge o starsand gas stretchesfor nearly 250,000 light-years and joins this famou peculiarpair of galaxies cataloge as Arp 295.The cosmic bridge between th galaxies and the long tail extendingbelow and right of picture center are strong evidencethat these two immense star systems hav passed close to each otherin the past, allowing violent tides induced by mutual gravityto create th eye-catching plumes of stellar material.Whil suchinteractions are drawn out overbillions of years, repeate closepassages should ultimately result inthe merger of this pair of galaxies into a larger singlegalaxy of stars.Althoug thisscenario does look peculiar, galactic mergers are thoughtto be common, with Arp 295 representing an early stage ofthis inevitable process.The Arp 295 pair are the largest of a loose grouping ofgalaxies about 270 millionlight-years distant toward the constellation Aquarius.This deep color imageof the region was recorded in September using the USN 1 metertelescope near Flagstaff, Arizona. <div class="blogger-post-footer"></div> </article> <article> <h1>Radio Jupiter</h1> <p>2009-07-12T19:03:00.001+03:00</p> Radio Jupiter<br><br><br><br>Thisview of ga giant Jupiter,made from data recorded at the VeryLarge Array radio observatory near Socorro, New Mexico,may not look too familiar.In fact, there is no sign of a bright, round planet striped withcloud bands, sporting Great Red Spot.Instead, th radiowaves mapped in this false-color imageare produced by energetic electrons trapped withinJupiter's intens magneticfield.The radio emitting region extends far beyond Jupiter's cloud tops,to over twice the visible radius of the planet,and surrounds Jupiter like an oversized version ofEarth's Van Allen radiation belt.While it glows strongly at radio wavelengths, Jupiter' radiationbelt is invisible in the more familia optical an infrared viewswhich show the Jovian cloud tops and atmospheric features inreflected sunlight. <div class="blogger-post-footer"></div> </article> <article> <h1>The Sombrero Galaxy from HST</h1> <p>2009-07-07T20:10:00.001+03:00</p> The Sombrero Galaxy from HST<br><br><br><br>Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge. Close inspection of the bulge in the above photograph shows many points of light that are actually globular clusters M104's spectacular dust rings harbor many younger and brighter stars, and show intricate details astronomers don't yet fully understand. The very center of the Sombrero glows across the electromagnetic spectrum, and is thought to house a large black hole. Fifty million-year-old light from the Sombrero Galaxy can be seen with a small telescope towards the constellation of Virgo. <div class="blogger-post-footer"></div> </article> <article> <h1>The Colorful Horsehead Nebula</h1> <p>2009-07-05T11:21:00.001+03:00</p> The Colorful Horsehead Nebula<br><br><br><br>While drifting through the cosmos, a magnificent interstellar dust cloud became sculpted by stellar winds and radiation to assume a recognizable shape. Fittingly named the Horsehead Nebula, it is embedded in the vast and complex Orion Nebula. The dark molecular cloud, roughly 1,500 light years distant, is cataloged as Barnard 33 and is visible only because its obscuring dust is silhouetted against the bright emission nebula IC 434. The bright blue reflection nebula NGC 2023 is visible on the lower left. The prominent horse head portion of the nebula is really just part of a larger cloud of dust which can be seen extending toward the bottom of the picture. A potentially rewarding but difficult object to view with a small telescope, this gorgeous representative-color image was taken by the large 3.6-m Canada-France-Hawaii Telescope in Hawaii, USA. <div class="blogger-post-footer"></div> </article> <article> <h1>A Near Record Ozone Hole in 2003</h1> <p>2009-07-02T20:36:00.001+03:00</p> A Near Record Ozone Hole in 2003<br><br><br><br>As expected, the ozone hole near Earth's South Pole is back again this year.This year's hole, being slightly larger than North America, is larger than last year but short of the record set on 2000 September 10 Ozone is important because it shields us from damaging ultraviolet sunlight. Ozone is vulnerable, though, to CFCs and halons being released into the atmosphere. Inte national efforts to reduce the use of these damaging chemicals appear to be having a positive effect on their atmospheric abundance. The relatively large size of the ozone hole this year, however, is attributed partly to colder than normal air in the surrounding stratosphere. The above picture of the ozone hole was taken on September 11 by TOMS on board the orbiting Earth Probe satellite. <div class="blogger-post-footer"></div> </article> <article> <h1>Apollo 12 Visits Surveyor 3</h1> <p>2009-07-02T19:37:00.000+03:00</p> Apollo 12 Visits Surveyor 3<br><br><br><br>Apollo 12 was the second mission to land humans on the Moon.The landing site was picked to be near the location of Surveyor 3, a robot spacecraft that had landed on the Moon three years earlier.In the above photograph, taken by lunar module pilo Alan Bean,mission commander Pete Conrad jiggles the Surveyor spacecraft to see how firmly it is situated.The lunar module is visible in the distance. Apollo 12brought back many photographs and moon rocks. Among the milestones achieved byApollo 12 was the deployment of the Apollo Lunar Surface Experiments Package, which carried out many experiments including one that measured the solar wind. <div class="blogger-post-footer"></div> </article> <article> <h1>X-Ray Moon</h1> <p>2009-06-23T21:48:00.001+03:00</p> X-Ray Moon<br><br><br><br>This x-ray image of the Moonwas made by the orbitin ROSAT Röntgensatellit) Observatory in 1990.In this digital picture, pixel brightness corresponds to x-ray intensity.Consider the image in three parts:the bright hemisphere of the x-ray moon,the darker half of the moon,and the x-ray sky background.The bright lunar hemisphere shine in x-rays because it scattersx-rays emitted by the sun.The background sky has an x-rayglow in part due tothe myriad of distant, powerful active galaxies, unresolvedin the ROSAT picture but recently detected in Chandra Observator x-ray images.But why isn't the dark half of the moon completely dark NewChandra results also suggest that a few x-rays only seemto come from the shadowedlunar hemisphere.Instead, theyoriginate in Earth's geocorona o extendedatmosphere which surrounds the orbiting x-ray observatories. <div class="blogger-post-footer"></div> </article> <article> <h1>Cold Comet Halley</h1> <p>2009-06-17T20:32:00.001+03:00</p> Cold Comet Halley<br><br><br><br>While this may not be the most esthetic image o Comet Halleythat you have ever seen, it is likely the most unique.The tiny cluster of pixels circled is th famouscomet along its orbit over4 billion (4,000,000,000) kilometers or 2 AUfrom the Sun - a record distance for a comet observation.Its last passage throug our neck of the woods in 1986 Comet Halleypresently cruises through the dim reaches of the outer solarsystem, almost as far away as outermost gas giant Neptune, and shows nosign of activity.Captured in March, this negative image is a composite ofdigital exposures made with threeof ESO's Very Large Telescopes.The exposures are registered on th moving comet, so thepicture shows background stars and galaxies as elongated smudges.An earth-orbiting satellite appears as a dark streak at the top CometHalley is clearly extremely faint here, but large earthboundtelescopes will be able to followit as it grows fainter still, reachingthe most distant point in its orbit, more than 5 billion kilometers(35 AU) from the Sun, in 2023. <div class="blogger-post-footer"></div> </article> <article> <h1>Reflections on the 1970s</h1> <p>2009-06-14T10:26:00.001+03:00</p> Reflections on the 1970s<br><br><br><br>The 1970s areoften overlooked.In particular, the beautiful grouping of reflection nebula NGC 1977,NGC 1975, and NGC 1973 in Orion areoften overlooked in favor ofthe substantial stellar nursery better known as the Orion Nebula.Found along the sword of Orion just nort of thebright Orion Nebula complex, these nebulae are also associate with Orion's giantmolecular cloud which lies abou 1,500 light-years away, butare dominated by the characteristic blue color of interstellardust reflecting light from hot young stars.In this sharpcolor image a portion of the Orion Nebula appearsalong the bottom border with the cluste of reflection nebulaeat picture center.NGC 1977 stretches across the field just below center,separated from NGC 1973 (above right) and NGC 1975 (above left)by dark regions laced with faint red emission fromhydrogen atoms.Taken together, the dark regions suggest to many theshape of a running man. <div class="blogger-post-footer"></div> </article> <article> <h1>An Unusual Event Over South Wales</h1> <p>2009-06-11T19:34:00.000+03:00</p> An Unusual Event Over South Wales<br><br><br><br>Jon Burnett, a teenager from South Wales, UK, was photographing some friends skateboarding last week when the sky did something very strange. By diverting his camera, he was able to document this rare sky event and capture one of the more spectacular sky images yet recorded. Roughly four minutes later, he took another picture of the dispersing trail. What is it? Experts disagree. The first guess wasa sofa-sized rock that exploded as a daytime fireball, but perhaps a better hypothesis is an unusual airplane contrail reflecting the setting Sun Bright fireballs occur over someplace on Earth nearly every day. A separate bolide, likely even more dramatic, struck India only a few days ago. Editor's note: The APOD text was updated on Oct. 1. <div class="blogger-post-footer"></div> </article> <article> <h1>The Sagittarius Dwarf Tidal Stream</h1> <p>2009-05-24T11:52:00.001+03:00</p> The Sagittarius Dwarf Tidal Stream<br><br><br><br>Is our Milky Way Galaxy out to lunch? Recent wide field images and analyses now indicate that our home galaxy is actually still in the process of devouring its closest satellite neighbor. This unfortunate neighbor, the Sagittarius Dwarf galaxy, is now seen to be part of a larger Sagittarius Tidal Stream, a loose filament of stars, gas, and possibly dark matter that entangles the Milky Way. An artist's depiction of the stream is shown above. Speculation also holds that the Sagittarius Dwarf was once pulled through the Milky Way disk very close to our Sun's current location. An important resulting realization is that galaxies contain a jumble of clumps and filaments of both dim and dark matter. <div class="blogger-post-footer"></div> </article> <article> <h1>Aurora Over the Chugach Mountains</h1> <p>2009-05-22T23:21:00.002+03:00</p> Aurora Over the Chugach Mountains<br><br><br><br>Auroras can make spectacular sights. Photographed above, flowing green auroras help the Moon illuminate the serene Portage Lake and the snowy Chugach Mountains near Anchorage, Alaska, USA.Although auroras might first appear to be moonlit clouds, they only add light to the sky and do not block background stars from view. Called northern lights in the northern hemisphere, auroras are caused by collisions between charged particles from the magnetosphere and air moleculeshigh in the Earth's atmosphere.If viewed from space, auroras can be seen to glow in X-ray and ultraviolet light as well. Predictable auroras likely occur a few days after a powerful magnetic event has been seen on the Sun. <div class="blogger-post-footer"></div> </article> <article> <h1>Our Galaxy in Stars, Gas, and Dust</h1> <p>2009-05-22T23:21:00.001+03:00</p> Our Galaxy in Stars, Gas, and Dust<br><br><br><br>The disk of our MilkyWay Galaxy is home to hot nebulae, cold dust, and billions of stars. The red nebulae visible in the above contrast-enhanced picture are primarily emission nebulae, glowing clouds of hydrogengas heated by nearby, bright, young stars. The blue nebulae are primarily reflection nebulae, clouds of gas and fine dust reflecting the light of nearby bright stars. Perhaps the most striking, though, are the areas of darkness, including the Pipe Nebula visible on the image top left. These are lanes of thick dust, many times containing relatively cold molecular clouds of gas. Dust is so plentiful that it obscures the Galactic Center in visible light, hiding its true direction until discovered earlylast century. The diffuse glow comes from billions of older, fainter stars like our Sun,which are typically much older than any of the nebulae. Most of the mass of ourGalaxy remains in a form currentlyunknown. <div class="blogger-post-footer"></div> </article> <article> <h1>Surveyor Slides</h1> <p>2009-05-16T08:28:00.001+03:00</p> Surveyor Slides<br><br><br><br>"Safe!"</i In September 1967 during regular season play),the Surveyor 5 lander actually slid several feetwhile making a successfulsoft landing on th Moon's Mare Tranquillitatis.Equipped with television cameras and soil sampling experiments the US Surveyor spacecraft were intended to determineif the lunar surfac at chosen locations was saf for the planned Apollo landings.Surveyor 5 touched down on the inside edge of a smallcrater inclined at about 20 degrees.Its footpad slipped an dug the trench visible in the picture.Covered with dusty lunar soil,the footpad is about 20 inches in diameter. <div class="blogger-post-footer"></div> </article> <article> <h1>IC1340 in the Eastern Veil</h1> <p>2009-05-13T19:54:00.001+03:00</p> IC1340 in the Eastern Veil<br><br><br><br>These ghostly filaments of interstellar gas are just a smallpart of th expansiveVeil Nebula, seen against a rich fieldof background stars in th long-neckedconstellatio Cygnus.Also known as th Cygnus Loop, the Veil Nebula is supernova remnant,the expanding debris cloud created by a stellarexplosion whose light first reached planet Earthfrom 5,000 to 10,000 years ago.About 1,400 light-years away,the entire nebula now appearsto span over 3 degrees onthe sky, nearly 6 times the apparent size of the full moon,but is faint and can be difficult to see in small telescopes.The region captured i thisbeautiful, deep, color imageis located at the southern tip of the Veil' easterncrescent.It covers about 10 light-years at the distance ofthe Veil and is cataloged as IC1340. <div class="blogger-post-footer"></div> </article> <article> <h1>Logarithmic Spirals Isabel and M51</h1> <p>2009-05-10T19:31:00.001+03:00</p> Logarithmic Spirals Isabel and M51<br><br><br><br>Uncomfortably clos hurricane Isabel (left)and 30 million light-yeardistant galaxy M51 actually don't have much in common.For starters, Isabel was hundreds of miles across, while M51 (th Whirlpool Galaxy)spans about 50,000 light-years making them vastlydissimilar in scale, not to mention the extremely differentphysical interactions which control thei formation an evolution.But they do look amazingly alike, both exhibiting the shape of a simpleand beautiful mathematical curve known as logarithmicspiral, a spiral whose separation grows in geometricway with increasing distance from the center.Also known as th equiangular spiral, growth spiral, and Bernoulli'sspiral or spira mirabilis, this curve' rich properties have fascinate mathematicianssince its discovery by 17th century philosophe Descartes.Intriguingly, this abstract shape is much more abundant in naturethan suggested by the striking visual comparison above.Logarithmic spirals also describe, for example, the arrangement o sunflowerseeds, the shapes of nautilus shells, and .. cauliflower. <div class="blogger-post-footer"></div> </article> <article> <h1>M33 Spiral Galaxy in Triangulum</h1> <p>2009-05-10T17:46:00.001+03:00</p> M33 Spiral Galaxy in Triangulum<br><br><br><br>The small constellatio Triangulumin the northern sky harborsthis magnificent face-on spiral galaxy, M33.Its popular names include the Pinwheel Galaxy or justthe Triangulum Galaxy.M33's diameter spans over 50,000 light-years, making it third largest inthe LocalGroup of galaxies after the Andromeda Galaxy (M31), and ourown Milky Way.About 3 million light-years from the Milky Way, M33lies very close to the Andromeda Galaxy an observersin these two galaxies would likely have spectacular views ofeach other's grand spiral star systems.As for the view from planet Earth, thi sharp27 frame mosaic of M33 nicely shows off blue star clustersand pinkish star forming regions which trace the galaxy'sloosely wound spiral arms.In fact, the cavernous NGC 604 is the brighteststar forming region seen here, visiblealong an arm arcing above and to the rightof the galaxy center.Like M31, M33's population of well-measured variable starshave helped make this nearby spiral cosmicyardstick fo establishingthe distance scale of the Universe. <div class="blogger-post-footer"></div> </article> <article> <h1>Egging On the Autumnal Equinox</h1> <p>2009-05-08T23:16:00.001+03:00</p> Egging On the Autumnal Equinox<br><br><br><br>Today is the autumnal equinox -- should eggs be able to stand on end? This long-standing myth loses much of its mystique after a demonstration that eggs can be made to stand on end during any day of the year. Pictured above, Dr. Phil Plait Sonoma St. U.) acting as the Bad Astronomer balanced three raw eggs on end in late October 1998. Later, more modestly, his wife balanced five more. The little-appreciated fact that most eggshells have small bumps on them makes this seemingly impossible task achievable. Although, during an equinox, every place on Earth experiences an equal length day and night (12 hours each), this fact has no practical effect on egg stability. <div class="blogger-post-footer"></div> </article> <article> <h1>Opportunity Rockets Toward Mars</h1> <p>2009-05-02T14:38:00.001+03:00</p> Opportunity Rockets Toward Mars<br><br><br><br>Next stop: Mars. Two months ago, the second of two missions to Mars was launched from Cape Canaveral, Florida, USA above a Boeing Delta II rocket.The Mars Exploration Rover dubbed Opportunity is expected to arrive at the red planet this coming January. Pictured above, an attached RocketCam (TM) captures Opportunityseparating from lower booster stages and rocketing off towardMars.Upon arriving, parachutes will deploy to slow the spacecraft and surrounding airbags will inflate. The balloon-like package will then bounce around the surface a dozen times or more before coming to a stop. The airbags will then deflate, the spacecraft will right itself, and the Opportunity rover will prepare to roll onto Mars. A first rover named Spirit was successfully launched on June 10 and will arrive at Mars a few weeks earlier. The robots Spirit and Opportunity are expected to cover as much as 40 metres per day, much more than Sojourner, their 1997 predecessor. Spirit and Opportunity will search for evidence of ancient Martian water, from which implications might be drawn about the possibility of ancient Martian life. <div class="blogger-post-footer"></div> </article> <article> <h1>Inside the Eagle Nebula</h1> <p>2009-05-01T21:30:00.001+03:00</p> Inside the Eagle Nebula<br><br><br><br>From afar, the whole thing looks like an Eagle. A closer look at the Eagle Nebula, however, shows the bright region is actually a window into the center of a larger dark shell of dust. Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed. In this cavity tall pillars and round globules of dark dust and cold molecular gasremain where stars are still forming. Already visible are several young bright blue stars whose light and winds are burning away and pushing back the remaining filaments and walls of gas and dust. The Eagle emission nebula, tagged M16, lies about 6500 light years away, spans about 20 light-years, and is visible with binoculars toward the constellation of Serpens. The above picture combines three specific emitted colors and was taken with the 0.9-meter telescope on Kitt Peak, Arizona, USA. <div class="blogger-post-footer"></div> </article> <article> <h1>Apollo 11 Catching Some Sun</h1> <p>2009-04-19T12:24:00.000+03:00</p> Apollo 11 Catching Some Sun<br><br><br><br>Bright sunlightglints and long dark shadow dramatize thisimage of th lunar surfacetaken by Apollo 11 astronaut NeilArmstrong, the first to wal on the Moon.Pictured is the mission's lunar module, the Eagle,and spacesuited lunar module pilot Buzz Aldri unfurling a long sheet of foil also known as th Solar Wind Collector.Exposed facing the Sun, the foil trapped atoms streaming outwardin the solar wind, ultimately catching a sample o material from the Sun itself.Along with moon rocks and lunar soil samples, the solar wind collector wasreturned for analysisin earthbound laboratories. <div class="blogger-post-footer"></div> </article> <article> <h1>Galileo's Europa</h1> <p>2009-04-10T22:49:00.000+03:00</p> Galileo's Europa<br><br><br><br>Launched in 1989 and looping through the jovian system since late1995, the voyage of NASA' Galileospacecraft will soon come to an end.The spacecraft has bee targeted to plungedirectl intoJupiter this Sunday, September 21st, at about 30 miles per second.Its components will be vaporized in thegas giant's outer atmosphere.While Galileo's long voyage of explorationhas resulted in a spectacula scientificlegacy,the spacecraft's ultimate fate is related to perhapsits mos tantalizingdiscovery -- strong evidence for liquid oceanbeneath the frozen surface of Jupiter' moonEuropa.Galileo is now almost completely out of fuel for maneuvers,so this intentional collision with Jupiter will preventany unintentional future collision with Europaand the possibility of contaminating the jovian moon withmicrobes from Eart hardy enough to survive in interplanetary space Colorimage data from the Galileo mission recorded between1995 and 1998 was used to create this depiction ofEuropa's cracked and icy surface The insetshows dark reddish, disrupted regions dubbed Thera and Thrace. <div class="blogger-post-footer"></div> </article> <article> <h1>Saturn by Three</h1> <p>2009-04-03T19:50:00.001+03:00</p> Saturn by Three<br><br><br><br>Thes threeviews of Saturn wererecorded by the Hubble Space Telescope on March 7th of thisyear, as the southern hemisphere of the solar system's most gorgeousplanet reached its maximum 27 degree tilttoward Earth.The images use to constructthe false-color pictures were madethrough a combination o filters covering theelectromagnetic spectrum from ultraviolet (top), to visible (middle)and infrared (bottom) wavelengths highlighting differen features in the Saturnian atmospheric bands and rings.Well known for its bright ringsystem and large,mysterious moon Titan,gas gian Saturn isalso a planet with a dynamic atmosphere and high-speed winds.In fact, in the 1980s Voyagerspacecraft measured equatorialwinds of over 1,000 miles per hour.Giant storm systems,comparable in size to planet Earth itself, have been see erupting in Saturn's cloud tops. <div class="blogger-post-footer"></div> </article> <article> <h1>The 2MASS Galaxy Sky</h1> <p>2009-03-25T22:30:00.001+02:00</p> The 2MASS Galaxy Sky<br><br><br><br>Are the nearest galaxies distributed randomly?A plot of over one million of the brightest "extended sources" detected by the Two Micron All Sky Survey (2MASS) shows that they are not. The vast majority of these infrared extended sources are galaxies. Visible above is an incredible tapestry of structure that provides limits on how the universe formed and evolved. Many galaxies are gravitationally bound together to form clusters, which themselves are loosely bound into superclusters, which in turn are sometimes seen to align over even larger scale structures. In contrast, very bright stars inside our own Milky Way Galaxy cause the vertical blue sash. <div class="blogger-post-footer"></div> </article> <article> <h1>Hurricane Isabel Approaches</h1> <p>2009-03-21T21:08:00.001+02:00</p> Hurricane Isabel Approaches<br><br><br><br>Where will Hurricane Isabel go? One of the stronger storm systems of modern times appears headed for one the more populated seaboards on planet Earth -- the east coast of the USA. Hurricane Isabel, pictured yesteday as it passed east of the Bahamas, has flirted with category 5 status, the most powerful hurricane category.Hurricanes are huge swirling storms with cloudsystems typically larger than a state. Tropical cyclones, called hurricanes inEarth's Western Hemisphere and typhoons in the Eastern Hemisphere, get their immense energy from warm evaporated ocean water. As this water vapor cools andcondenses, it heats the air, lowers pressure and hence causes cooler air to comeswooshing in. Winds can reach over 250 kilometers per hour and become very dangerous. Much remains unknown abou cyclones, including how they are formed and the exact path they will take. <div class="blogger-post-footer"></div> </article> <article> <h1>Globular Cluster M3</h1> <p>2009-03-21T21:06:00.001+02:00</p> Globular Cluster M3<br><br><br><br>This huge ball of stars predates our Sun. Long before humankind evolved, before dinosaurs roamed, and even before our Earth existed, ancient globs of stars condensed and orbited a young Milky Way Galaxy. Of the 200 or so globular clusters that survive today, M3 is one of the largest and brightest, easily visible in the Northern hemisphere with binoculars. M3 contains about half a million stars, most of which are old and red. Light takes about 100,000 years to reach us from M3, which spans about 150 light years. The above picture is a composite of blue and red images. <div class="blogger-post-footer"></div> </article> <article> <h1>The Crab Nebula from VLT</h1> <p>2009-03-19T22:11:00.001+02:00</p> The Crab Nebula from VLT<br><br><br><br>The Crab Nebula, filled with mysterious filaments, is the result of a star that was seen to explode in 1054 AD. This spectacular supernova explosion was recorded by Chinese and (quite probably) Anasazi Indian astronomers. The filaments are mysterious because they appearto have less mass than expelled in the original supernovaand higher speed than expected from a free explosion.In the above picture taken recently from Very Large Telescope, the color indicates what is happening to the electrons in differentparts of the Crab Nebula.Red indicates the electrons are recombining with protons to form neutral hydrogen,while blue indicates the electrons are whirling around the magnetic fieldof the inner nebula. In the nebula's very center lies a pulsar: a neutron star rotating, in this case, 30 times a second. <div class="blogger-post-footer"></div> </article> <article> <h1>NGC 3132 The Eight Burst Nebula</h1> <p>2009-02-26T23:59:00.001+02:00</p> NGC 3132 The Eight Burst Nebula<br><br><br><br>It's the dim star, not the bright one, near the center o NGC 3132that created this odd but beautiful planetary nebula. Nicknamed the Eight-Burst Nebula and the Southern Ring Nebula, the glowing gas originated in the outer layers of a star like our Sun. In thi representativecolor picture, the hot blue pool of light seen surrounding this binary system is energized by the hot surface of the faint star. Although photographed to explore unusual symmetries, it's the asymmetries that help make this planetary nebula so intriguing. Neither the unusual shape of the surrounding cooler shell nor the structure and placements of the cool filamentary dust lanes running across NGC 3132are well understood. <div class="blogger-post-footer"></div> </article> <article> <h1>A Note on the Perseus Cluster</h1> <p>2009-02-17T22:13:00.001+02:00</p> A Note on the Perseus Cluster<br><br><br><br>A truly enormous collection of thousands of galaxies, th Perseus Cluster - like othe large galaxy clusters - isfilled with hot, x-ray emitting gas.The x-ray hot gas(not the individual galaxies) appearsin the left panel above, a false colo imagefrom the Chandra Observatory.The bright central source flanked by tw dark cavities isthe cluster's supermassive black hole.At right, the panel shows th x-ray imagedata specially processedto enhance contrasts and reveals a strikingly regularpattern of pressure wave rippling throughthe hot gas. In other words soundwaves, likely generated by bursts ofactivity from the black hole, are ringing through thePerseus Galaxy Cluster.Astronomers infer that these previously unknown sound waves are asource of energy which keeps the cluster gas so hot So what note is the Perseus Cluster playing?Estimates of the distance between the wave peaks and sound speedin the cluster gas suggeststhe cosmic note is about 57 octaves below B-flat above middle C. <div class="blogger-post-footer"></div> </article> <article> <h1>NGC 3370 A Sharper View</h1> <p>2009-02-16T20:15:00.001+02:00</p> NGC 3370 A Sharper View<br><br><br><br>Similar in size and grand design to ou ownMilky Way, spiral galaxy NGC 3370 lies about 100 millionlight-years away toward the constellation Leo.Recorde herein exquisite detail by the Hubble Space Telescope' Advanced Camera for Surveys,the big, beautiful face-on spiral does steal the show,but the sharp image also reveals an impressive array ofbackground galaxies in the field, strewn acrossthe more distant Universe.Looking within NGC 3370 theimage data has proved sharp enoughto study individual pulsating stars known a Cepheids whichcan be used to accurately determine this galaxy's distance.NGC 3370 was chosen for this study because in 1994the spiral galaxy was also home to a well studied stellarexplosion -- a type Ia supernova.Combining the known distance to thi standard candle supernova,based on the Cepheid measurements, with observationsof supernovae at even greater distances,can reveal the size and expansion rate of th Universeitself. <div class="blogger-post-footer"></div> </article> <article> <h1>Aurora Over Clouds</h1> <p>2009-02-15T00:29:00.001+02:00</p> Aurora Over Clouds<br><br><br><br>Aurorae usually occur high above the clouds. The auroral glow is created when fast-moving charged particles fromthe Earth's magnetosphere impact air molecules high in the Earth's atmosphere. An oxygen molecule, for example, will emit a green light when reacquiring an electron lost during a collision. The lowest part of an aurora will typically occur at 100 kilometers and up, while most clouds usually exist only below about 10 kilometers. The relative heights of clouds and auroras are shown clearly in the above picture taken last month from near Quebec City, Canada.The most likely time to see an aurora is around midnight. <div class="blogger-post-footer"></div> </article> <article> <h1>A Gemini Sky</h1> <p>2009-02-14T23:57:00.001+02:00</p> A Gemini Sky<br><br><br><br>Where will Gemini take us tonight?It is dusk and Gemini North, one of the largest telescopes on planet Earth, prepares to peer into the distant universe. Gemini's flexible 8.1-mirror has taken already effectively taken humanity to distant stars, nebulas, galaxies, and quasars, telling us about the geometry, composition, and evolution of our universe.The above picture is actually a composite of over 40 images taken while the Gemini dome rotated, later adding an image of the star field taken from the same location.The Gemini dome is not transparent -- it only appears so because it rotated during the exposures of this image.The constellations of Scorpius and Sagittarius can be seen above the dome, as well as the sweeping band of our Milky Way Galaxy,including the direction toward the Galactic center.Gemini North's twin, Gemini South, resides in Cerro Pachn, Chile. This night, 2003 August 19, Gemini North took us only into the outer Solar System, observing Pluto in an effort to better determine the composition of its thin atmosphere. <div class="blogger-post-footer"></div> </article> <article> <h1>Stars and Dust of the Lagoon Nebula</h1> <p>2009-02-11T23:15:00.001+02:00</p> Stars and Dust of the Lagoon Nebula<br><br><br><br>The large majestic Lagoon Nebula is home for many young stars and hot gas. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebulae is so big and bright thatit can be seen without a telescope toward the constellation of Sagittarius. Many bright stars are visible from NGC 6530, an open cluster that formed in the nebula only several million years ago.The greater nebula, also known as M8 and NGC 6523, is named "Lagoon" for the band of dust seen to the left of the open cluster's center. A bright knot of gas and dust in the nebula's center is known as the Hourglass Nebula. The above picture is a digitally sharpened composite of exposures taken in specific colors of light emitted by sulfur (red), hydrogen (green), and oxygen (blue).Star formation continues in the Lagoon Nebula as witnessed by the many globules that exist there. <div class="blogger-post-footer"></div> </article> <article> <h1>The Galactic Center in Infrared</h1> <p>2009-02-08T00:29:00.001+02:00</p> The Galactic Center in Infrared<br><br><br><br>The center of our Galaxy is a busy place. In visible light, much of the Galactic Center is obscured by opaque dust. In infrared light, however, dust glows more and obscures less, allowing nearly one million stars to be recorded in the above photograph. The Galactic Center itself appears on the right and is located about 30,000 light years away towards the constellation of Sagittarius. The Galactic Plane of our Milky Way Galaxy, the plane in which the Sun orbits, is identifiable by the dark diagonal dust lane. The absorbing dust grains are created in the atmospheres of cool red-giant stars and grow in molecular clouds. The region directly surrounding the Galactic Center glows brightly in radio and high-energy radiation, and is thought to house a large black hole. <div class="blogger-post-footer"></div> </article> <article> <h1>Jupiter Unpeeled</h1> <p>2009-02-04T08:14:00.001+02:00</p> Jupiter Unpeeled<br><br><br><br>SliceJupiterfrom pole to pole, peel back its outer layer of clouds,stretch them onto a flat surface ... and for all yourtrouble you'd end up with something that looks a lot like this.Scrolling right will reveal the full picture a color mosaic o Jupiterfrom the Cassini spacecraft.The mosaic is actually a single frame from a fourteen framemovie constructed from image data recorded by Cassiniduring it leisurelyflyby of the solar system's largestplanet in late 2000 Theengaging movie approximatesJupiter's cloud motions over 24 jovian rotations.To make it, a series of observations coveringJupiter's complete circumference60 degrees north and southof the equator were combined in an animate cylindricalprojection map of the planet.As in the familiar rectangular-shaped wall maps of th Earth's surface, therelative sizes and shapes of features arecorrect near the equator but become progressively more distortedapproaching the polar regions.In the Cassini movie, which also features guest appearancesby moons Io an Europa, the smallest cloud structuresvisible at the equator are about 600 kilometers across. <div class="blogger-post-footer"></div> </article> <article> <h1>SIRTF Streak</h1> <p>2009-02-04T08:13:00.001+02:00</p> SIRTF Streak<br><br><br><br>Streaking skyward, Boeing Delta 2-Heavy rocket carries NASA' Space InfraRedTelescope Facility (SIRTF) aloft duringthe early morning hours of August 25th.The dramatic scene was recorded in a time exposure from the pierin Jetty Park at the northern end of Cocoa Beach, Florida,about 2.5 miles from the Cape Canaveral launch site.SIRTF (sounds like "sir tiff") will explore the distan Universe in infrared lightas the fourth and finalsatellite observatory in NASA' Great Observatories Program.The three other large astrophysics satellites were designedfor higher energies in the electromagnetic spectrum, with th Hubble Space Telescopeoperating near visible wavelengths, th Compton Gamma Ray Observatoryinstruments sensitive to gamma rays, and th Chandra Observatorydetecting cosmic x-rays.SIRTF has been launched into a Earth-trailingsolar orbit to reduce its exposure to infrared radiation fromour fair planet.Cooled by an on board supply o liquid helium,SIRTF's infrared detectors will operate at near absolute zerotemperatures.Presently, SIRTF's systems are undergoing a 90-day check out. <div class="blogger-post-footer"></div> </article> <article> <h1>Composite Crab</h1> <p>2009-01-25T21:47:00.001+02:00</p> Composite Crab<br><br><br><br>The Crab Pulsar, a city-sized, magnetize neutron starspinning 30 times a second,lies at the center of this composite image of the inner region ofthe well-known CrabNebula.The spectacular picture combines optical data (red) from th Hubble Space Telescopeand x-ray images (blue) from th ChandraObservatory, also used in the popula CrabPulsar movies.Like cosmicdynamo the pulsar powers the x-rayand optical emission from the nebula, acceleratingcharged particles and producing the eerie, glowing x-ray jets.Ring-like structures are x-ray emitting regions wherethe high energy particles slam into the nebular material.The innermost ring is about a light-year across.With more mass tha theSun and the density of a atomic nucleus,the spinning pulsar is the collapsed core of a massive starthat exploded, while the nebula is theexpanding remnant of the star's outer layers.The supernova explosion was witnessed i the year 1054. <div class="blogger-post-footer"></div> </article> <article> <h1>Galactic Supernova Remnant IC 443</h1> <p>2009-01-17T06:55:00.003+02:00</p> Galactic Supernova Remnant IC 443<br><br><br><br>About 8000 years ago, a star in our Galaxy exploded. Ancient humans might have noticed the supernova as a temporary star, but modern humans can see the expanding shell of gas even today. Pictured above, part of the shell of IC 443 is seen to be composed of complex filaments, some of which are impacting an existing molecular cloud. Here emission from shock-excited molecular hydrogen is allowing astronomers to study how fast moving supernova gas affects star formation in the cloud. Additionally, astronomers theorize that the impact accelerates some particles to velocities near the speed of light. Supernova remnant IC 443 is also known to shine brightly also in infrared and X-ray light. <div class="blogger-post-footer"></div> </article> <article> <h1>Contemplating Mars</h1> <p>2009-01-17T06:55:00.001+02:00</p> Contemplating Mars<br><br><br><br><title> APOD: 2003 September 2 - Contemplating Mars <div class="blogger-post-footer"></div> </article> <article> <h1>A Beautiful Trifid</h1> <p>2009-01-14T21:34:00.000+02:00</p> A Beautiful Trifid<br><br><br><br>The beautifu Trifid Nebula(aka M20),a photogenic study in cosmic contrasts, lies abou 5,000light-years away toward the nebula richconstellation Sagittarius.A star forming region in the plane of our galaxy,the Trifid alone illustrates three basic types ofastronomical nebulae;red emission nebulae dominated bylight from hydrogen atoms,blue reflection nebulae producedby dust reflecting starlight, anddark absorption nebulae wheredense dust clouds appear in silhouette.The bright emission nebula on the right, separated into threeparts by obscuring dust lanes, lends the nebula its popular name.Many details are apparent in thi gorgeoushigh-resolution imageof the Trifid.For example, light-year long pillars and jets sculpted bynewborn stars - visible here in the upper right-hand cornerof the emission nebula - appear in Hubble Space Telescop close-up imagesof the region. <div class="blogger-post-footer"></div> </article> <article> <h1>The View from Everest</h1> <p>2009-01-09T21:56:00.001+02:00</p> The View from Everest<br><br><br><br><title> APOD: 2003 August 31 - The View from Everest <div class="blogger-post-footer"></div> </article> <article> <h1>Recycling Cassiopeia A</h1> <p>2009-01-09T07:53:00.001+02:00</p> Recycling Cassiopeia A<br><br><br><br>For billions of years massive stars in our Milky WayGalaxy have lived spectacular lives. Collapsing from vast cosmicclouds, their nuclear furnacesignite and create heavy elements in their cores.After a few million years, th enriched material is blastedback into interstellar space where star formationbegins anew.The expanding debris cloud know asCassiopeia A is an exampleof this final phase of the stellar life cycle.Light from the explosion which created this supernova remnant wasprobably firs seenin planet Earth's sky just over 300 years ago,although it took that light more than 10,000 years to reach us.In this gorgeou Hubble Space Telescope image of cooling filamentsand knots in the Cas A remnant, lightfrom specific elements has been color coded to help astronomersunderstand the recycling of our galaxy' star stuff.For instance, red regions are dominated by emission from sulfur atomswhile blue shades correspond to oxygen Thearea shown is about 10 light-years across. <div class="blogger-post-footer"></div> </article> <article> <h1>The Mineral Moon</h1> <p>2009-01-07T23:55:00.001+02:00</p> The Mineral Moon<br><br><br><br>Evenif the Moon really were made o green cheese it probably wouldn'tlook this bizarre.Still, thi mosaicof 53 images was recorded by theJupiter-bound Galileo spacecraft asit passed near our own larg naturalsatellite in 1992.The pictures were recorded through three spectral filters andcombined in an exaggerated false-color schem to explore th compositionof the lunar surface aschanges in mineral content produce subtl color differences inreflected light.Familiar to earthdwellers, the lunar near side ison the left, but the space-based view looks down on theMoon's north pole locatedin the upper half of the image near the shadow line.Blue to orange shades indicate volcanic lava flows.The dark blu Mare Tranquillitatisat the lower left is richer intitanium bearing minerals than the green and orange maria above it.Near the bottom of the image and to the right of Tranquillitatis is the dark oval-shaped Mare Crisium surrounded byshocking pink colors indicating material of th lunarhighlands. <div class="blogger-post-footer"></div> </article> <article> <h1>Mars Rising Behind Elephant Rock</h1> <p>2009-01-04T13:14:00.001+02:00</p> Mars Rising Behind Elephant Rock<br><br><br><br><title> APOD: 2003 August 28 - Mars Rising Behind Elephant Rock <div class="blogger-post-footer"></div> </article> <article> <h1>Big Mars from Hubble</h1> <p>2009-01-04T00:03:00.002+02:00</p> Big Mars from Hubble<br><br><br><br><title> APOD: 2003 August 27 - Big Mars from Hubble <div class="blogger-post-footer"></div> </article> <article> <h1>Earth Webcam Catches Mars Rotation</h1> <p>2009-01-04T00:03:00.000+02:00</p> Earth Webcam Catches Mars Rotation<br><br><br><br><title> APOD: 2003 August 26 - Earth Webcam Catches Mars Rotation <div class="blogger-post-footer"></div> </article> <article> <h1>The Northern Milky Way</h1> <p>2009-01-04T00:01:00.003+02:00</p> The Northern Milky Way<br><br><br><br><title> APOD: 2003 August 25 - The Northern Milky Way <div class="blogger-post-footer"></div> </article> <article> <h1>Valles Marineris The Grand Canyon of Mars</h1> <p>2009-01-04T00:01:00.001+02:00</p> Valles Marineris The Grand Canyon of Mars<br><br><br><br>The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Recently, several geologic processes have been identified in the canyon. The above mosaic was created from over 100 images of Mars taken by Viking Orbiters in the 1970s. News: Mars closest in over 50,000 years on Wednesday <div class="blogger-post-footer"></div> </article> <article> <h1>The Tarantula Zone</h1> <p>2009-01-04T00:00:00.000+02:00</p> The Tarantula Zone<br><br><br><br>TheTarantula Nebula is more than 1,000 light-years across -a giant emission nebula within ou neighboring galax the Large Magellanic Cloud.Inside this cosmic arachnid lies a central young cluster of massivestars, cataloged a R136, whose intense radiation and strong windshave helped energize the nebular glow and shape the spidery filaments.In thi impressive color mosaicof images from th Wide-Field Imagercamera on ESO's 2.2 meter telescope at La Silla Observatory, otheryoung star clusters can be seen still within th nebula's grasp.Also notable among the denizensof the Tarantula zone are severa dark cloudsinvading the nebula's outer limits as well asthe dense clusterof stars NGC 2100 at the extreme left edge of thepicture.The small but expanding remnant ofsupernova 1987a, the closest supernovain modern history,lies just off the lower right corner of the field.The rich mosaic's field of view covers an area on the skyabout the size ofthe full moon in the souther constellation Dorado. <div class="blogger-post-footer"></div> </article> <article> <h1>Shadow Rise</h1> <p>2009-01-03T23:56:00.001+02:00</p> Shadow Rise<br><br><br><br>As the Sun sets, the Earth'sshadow rises up from the east.The subtle beauty o thisdaily apparition is often overlookedin favor of the brighter, more colorfulwestern horizon.But while gazing toward a nearly full rising Moon on August 9,astronomer Steve Mandel admired the shadow rise from his drivewaynear Soquel, California, USA.His view looks east from the northern tip of Monterey Bay towardFremont Peak, the highest point in the small mountain range onthe horizon TheEarth's rising shadow is cast through thedense atmosphere and is seen in his picture as the dark blue bandalong the horizon, bounded above by a pinkish purple glow orantitwilight arch.Also known as the Belt of Venus,the arch's lovely color is dueto backscattering o reddenedlight from the setting Sun. <div class="blogger-post-footer"></div> </article> <article> <h1>X-Rays from M17</h1> <p>2009-01-01T11:13:00.001+02:00</p> X-Rays from M17<br><br><br><br>About 5,00 light-yearsaway, toward the constellation Sagittariusand the center of our galaxy,lies the bright star forming regio cataloged as M17.In visible light, M17's bowed and hollowed-out appearance has resulted inmany popular nameslike the Horseshoe, Swan, Omega, and Lobsternebula.But what hassculpted this glowing gas cloud?Thi ChandraObservatory image of x-rays from M17 provides a clue.Many massive young stars are responsible for the pinkcentral region of the false-colo x-ray picture, their collidingstellar winds producing th multimilliondegree gas cloudwhich extends ten or so light-years to the left.When comparedwith visible light images,this x-ray hot cloud is partly surrounded by the nebula's cooler gas.In fact, having carved out a central cavitythe hot gas seems to be flowing out of the horseshoeshape like champagne from an uncorked bottle ...suggesting yet another name for star formingregion M17. <div class="blogger-post-footer"></div> </article> <article> <h1>The E Nebula in Aquila</h1> <p>2008-12-28T23:23:00.003+02:00</p> The E Nebula in Aquila<br><br><br><br>Several unusual strands of darkness are prominent toward the constellation of Aquila. This particular dark nebula is known as the E Nebula, for its evocative shape, or B142 and B143, for its position(s) on a list of such nebula compiled by Barnard. The E Nebula spans roughly the angle of a full Moon and lies about 2000 light years distant. The nebula can be seen with binoculars and is particularly visible during the summer months in Earth's northern hemisphere. Other names for dark nebula include absorption nebula, as they efficiently absorb visible light emitted behind them, and molecular clouds, as they frequently attain temperatures low enough so that several different types of stable molecules can exist. The low temperatures of these interstellar clouds facilitate the formation of dense knots of gas that may then collapse into bright stars. <div class="blogger-post-footer"></div> </article> <article> <h1>Mars Through a Small Telescope</h1> <p>2008-12-28T23:23:00.001+02:00</p> Mars Through a Small Telescope<br><br><br><br>How does Mars appear through a small telescope? Viewed with the unaided eye or through a small telescope, possibly the most striking part of Mars' appearance is its red color. The color derives from rust, iron oxide, which composes perhaps 10% of the Martian soil. The oxygen that rusts the surface iron on Mars originates predominantly from carbon dioxide gas, which composes 95% of the Martian atmosphere. Mars nears its closest approach with Earth in nearly 60 millennia on August 27, the red planet continues to appear larger, brighter, and a good target for sky enthusiasts. Pictured above, Mars was captured from the Canary Islands of Spain during three days in three different orientations earlier this month. Visible through the small telescope are white polar caps of water and carbon-dioxide ice, light red areas rich in lightly colored craters, and dark red areas dominated by relatively smooth lowlands. <div class="blogger-post-footer"></div> </article> </main></body></html>