The E Nebula in Aquila

The E Nebula in Aquila



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.

Mars Through a Small Telescope

Mars Through a Small Telescope



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.

Bright Lights, Dark City

Bright Lights, Dark City



Last Thursday, millions of people had an unexpectedly good view of a dark night sky. Usually, the reflection of city lights off of local air impurities makes it hard for casual observers to see more than a handful of stars from a bright urban area. A large power outage in northeast North America, however, dimmed most city lights and brought unfamiliar celestial wonders to many who looked up. The unexpected starscape was perhaps a small perk in the face of hardships endured by many during the black out. Prominent in the above four-image digital montage are two of the few celestial wonders that can be seen even above the usual glare of cit light pollution: the Moon and Mars. Both appear on the far left, with Mars to the upper right of the Moon. Scrolling right will show how eerily dark New York City appeared from across the Hudson River in New Jersey at about 10 pm on 2003 August 14. Visible lights are mostly attributable to cars, local power generators, flashlights, and candles.

Natural Saturn On The Cassini Cruise

Natural Saturn On The Cassini Cruise



What could you see approaching Saturn aboard a interplanetary cruise ship?Your view would likely resembl thissubtly shaded image of the gorgeous ringed gas giant.Processed by the HubbleHeritage project, the picture intentionallyavoids overemphasizing color contrasts and presents natural looking Saturnwith cloud bands, storms, nearl edge-on rings, and the small round shadowof the moon Enceladus near the center of the planet's disk.Of course, seats were not available on the only ship currently en route, th Cassinispacecraft.Cassini flew byJupiter at the turn of the millennium and i scheduledto arrive at Saturn in the year 2004.After an extended cruise to a world 1,400 million kilometer from the Sun, Cassini will tour th Saturniansystem, conducting a remote, robotic explorationwith software and instrument designed by denizens of planet Earth.

Thackeray's Globules

Thackeray's Globules



Rich star fieldsand glowing hydrogen gas silhouettedense, opaque clouds of interstellar gas and dustin this Hubble Space Telescop close-upof IC 2944, a bright star forming regio in Centaurus, 5,900 light-years away.The largest of these dark globules,first spotted by South African astronomer A. D. Thackeray in 1950,is likely two separate but overlapping clouds, each more than on light-year wide.Combined the clouds contain materia equivalent to about15 times the mass of the Sun, but will they actuall collapse to form massive stars?Along with other data, th sharpHubble images indicate thatThackeray's globules are fractured and churning as a resultof intense ultraviolet radiation from young, hot stars alreadyenergizing and heating the bright emission nebula.These and similar dark globulesknown to be associated with otherstar forming regions may ultimately be dissipatedby their hostile environment --like cosmic lumps of butter in a hot frying pan.

Sedimentary Mars

Sedimentary Mars



High-resolution imaging of an area in the Schiaparelli Basin of Marson June 3 by the MGS Mars Orbiter camera produce thisstunning exampleof layered formations within an old impact crater.On planet Earth, such structureswould be seen in sedimentary rock-- material deposited at the bottom of ancient lakes or oceansand then subsequently weathered away to reveal th layers.With the Sun shinin from the left,the central layer appearsto stand above the others within the 2.3 kilometerwide crater.The crater could well have been filled with water inMars' distant past, perhaps resting at thebottom of a lake filling th Schiaparelli impact basin.Still, such layers might also have been formed by material settling outof the windy martian atmosphere.As satellites continue to examine the martian surface from orbit,NASA's Spirit and Opportunityspacecraft will attempt to land onon Mars early next year to further explore th tantalizinghistory of water on the Red Planet.

Dark Matter Map

Dark Matter Map



The total mass within giant galaxy cluste CL0025+1654,about 4.5 billio light-years away,produces a cosmic gravitational lens - bendinglight as predictedby Einstein's theory of gravity and forming detectable imagesof even more distant background galaxies.Of course, the totalcluster mass is the sum of the galaxies themselves, seen asordinary luminous matter, plus the cluster'sinvisible dark matter whos natureremains unknown.But by analyzing the distribution of luminous matter and theproperties of the gravitational lensingdue to total cluster mass,researchers have solved the problem of tracingthe dark matter layout Their resulting mapshows the otherwise invisible dark matter in blue,and the positions of the clustergalaxies in yellow The work,based on extensive Hubble Space Telescope observations,reveals that the cluster' darkmatter is not evenly distributed, butfollows the clumps of luminous matter closely.

Mars Rising Behind Poodle Rock

Mars Rising Behind Poodle Rock



Have you seen Mars lately? As Earth and Mars near their closest approach in nearly 60,000 years on August 27, the red planet has begun to appear dramatically bright and show interesting details through telescopes and binoculars. Although not yet visible at sunset, Mars can be seen rising increasingly earlier in the evening. Once above the horizon, Mars is easy to spot, as it sports a distinct orange-red hue and it is the brightest object in the sky after the Sun, the nearby Moon, and Venus.After Earth overtakes Mars in their respective solar orbits, Mars will be visible right from sunset, although its historic brightness will then begin to fade. Pictured above, Mars was captured rising in the south east next to Poodle Rock in Valley of Fire State Park, Nevada, USA.

X-rays from Stephan s Quintet

X-rays from Stephan s Quintet



Stephan'sQuintet is a picturesque but clearly troubledgrouping of galaxies about 300 million light-years awaytoward the high-flying constellatio Pegasus.Spanning over 200,000 light-years at that distance thiscomposite false-color imageillustrates the powerful nature of thi multiplegalaxy collision,showing x-ray data from th ChandraObservatory in blue superposed on optical data in yellow.The x-raysfrom the central blue cloud running verticallythrough the image are produced bygas heated to millions of degrees by an energeticshock on a cosmic scale.The shock was likely the result of the interstellar gasin the large spiral galaxy, seen immediately to the rightof the cloud,colliding with the quintet's tenuous intergalactic gasas this galaxy plunged through group's central regions.In fact, over billions of years, repeated passages of thegroup galaxies through the hot intergalacticgas should progressively strip them of their own starforming material.In this view, the large spiral galaxy just seen peekingabove the bottom edge is an unrelated foreground galaxya mere 35 million light-years distant.

Elements of the Swan Nebula

Elements of the Swan Nebula



In the depths of the dark clouds of dust and molecular gas known as M17, stars continue to form. Also known as the Omega Nebula and Horseshoe Nebula, the darkness of M17's molecular clouds results from background starlight being absorbed by thick filaments of carbon-based smoke-sized dust. As bright massive stars form, they produce intense and energetic light that slowly boils away the dark shroud. Colors in the above image were picked to highlight specific elements that emit nebular light: red indicates emission from sulfur, green from hydrogen, and blue from oxygen. The Swan Nebula is visible with binoculars towards the constellation of Sagittarius, lies 5000 light-years away, and spans 20 light-years across.

Lunation

Lunation



Our Moon's appearance changes nightly. This time-lapse sequence shows what our Moon looks like during a lunation, a complete lunar cycle. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The Moon always keeps the same face toward the Earth. The Moon's apparent size changes slightly, though, and a slight wobble called a libration is discernable as it progresses along its elliptical orbit.During the cycle, sunlight reflects from the Moon at different angles, and so illuminates different features differently. A full lunation takes about 29.5 days, just under a month (moon-th).

A Perseid Aurora

A Perseid Aurora



Just after the Moon set but before the Sun rose in the early morning hours of 2000 August 12, meteors pelted the Earth from the direction of the constellation Perseus, while ions pelted the Earth from the Sun. The meteors were expected as sub-sand grains long left behind by Comet Swift-Tuttle annually create the Perseids Meteor Shower. The aurorae were unexpected, however, as electrons, protons, and heavier ions raced out from a large Coronal Mass Ejection that had occurred just days before on the Sun. In the foreground is Hahn's Peak, an extinct volcano in Colorado, USA.The Perseid meteor shower peaks this year over the next few days, with as much as one bright meteor per minute visible from some locations.

Blue Stragglers in NGC 6397

Blue Stragglers in NGC 6397



In our neck of th Galaxy stars are to far apartto be in danger of colliding, but in the dense cores o globular star clusters star collisionsmay be relatively common.In fact researchers have evidence that theclosely spaced blue stars near the center of the above image taken by the orbiting Hubble Space Telescopewere formed when stars directly collided.Pictured is the central region o NGC 6397, globular clusterabout 6,000 light-years distant, whos stars all formed at about the same time NGC 6397'smassive stars have long since evolved off the main sequence,exhausting their central supplies o nuclear fuel.This should leave the cluster with only old low mass stars; faint redmain sequence stars and brighter blue an red giants.However, spectroscopic data show that the indicated stars, descriptivelydubbed blue stragglers, are clearlymain sequence stars which are too blue and too massive to still be there Suggestively the stragglers appear to be two and occasionally threetimes as massive as the lower mass cluster starsotherwise present supporting evidence fortheir formation from two and even three star collisions.

Palomar at Night

Palomar at Night



What's wrong with this picture?The summer night sky is clear, andmoonlight illuminates the dome of th Hale 200-inch Telescope a Palomar Observatory,northeast of San Diego, California, USA.The familiar stars of th Teapot asterism in the constellatio Sagittariusshine above the dome and to the right.In fact, the only thing wrong with the picture is thatthe observatory dome's two massive shuttersare closed tight ... on a clear night.This extremely unusual situation is a precautionprompted by the presence of airborne ash and smoke fro wildfiresin the area on July 17which could have damaged th historic mirror's aluminum coating.Amateur astronomer Greg Redfern notes that thisyear has been a particularly bad one for observatories andwildfires, with th Mt. StromloAustralian Observatorydisaster and fires also threatening telescopes on MountLemmon near Tucson, Arizona.

Dusty Galaxy Centaurus A

Dusty Galaxy Centaurus A



Why is peculiar galaxy Centaurus A so dusty? Dramatic dust lanes that run across the galaxy's center mark Cen A. These dust lanes are so thick they almost completely obscure the galaxy's center in visible light. This is particularly unusual as Cen A's red stars and round shape are characteristic of a giant elliptical galaxy, a galaxy type usually low in dark dust. Cen A, also known as NGC 5128, is also unusual compared to an average elliptical galaxy because it contains a higher proportion of young blue stars and is a very strong source of radio emission. Evidence indicates that Cen A is likely the result of the collision of two normal galaxies. During the collision, many young stars were formed, bu details of the creation of Cen A's unusual dust belts are still being researched. Cen A lies only 13 million light years away, making it the closest active galaxy. Cen A spans 60,000 light years and can be seen with binoculars toward the constellation of Centaurus.

Shuttle Ferry

Shuttle Ferry



How does a space shuttle that landed in California get back to Florida for its next launch? The answer is by ferry. NASA operates two commercial Boeing 747 airplanes modified to carry a space shuttle on their backs. Designated officially as Shuttle Carrier Aircraft or SCA, the 747s were made for commercial flights but bolstered by NASA with several struts, stabilizers, and electronic monitors. Spanning about 70 meters in length, the two aircraft's combined mass is nearly 150,000 kilograms. Pictured above, the space shuttle Atlantis is shown being ferried back to NASA Kennedy Space Center in Florida in September 1998.

In the Center of the Virgo Cluster

In the Center of the Virgo Cluster



The Virgo Cluster of Galaxies is the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster is so close that it spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon. It contains over 100 galaxies of many types - including spiral, elliptical, and irregular galaxies. The Virgo Cluster is so massive that it is noticeably pulling our Galaxy toward it. The cluster contains not only galaxies filled with stars but also gas so hot it glows in X-rays. Motions of galaxies in and around clusters indicate that they contain more dark matter than any visible matter we can see. Pictured above, the center of the Virgo cluster might appear to some as a human face, and includes bright Messier galaxies M86 at the top, M84 on the far right, NGC 4388 at the bottom, and NGC 4387 in the middle.

Ice Fishing for Cosmic Neutrinos

Ice Fishing for Cosmic Neutrinos



Scientists are melting holes in the bottom of the world. In fact, several holes have been melted near the South Pole, and they are now being used as astronomical observatories. Astronomers with the Antarctic Muon and Neutrino Detector Array (AMANDA) lower into each vertical lake a string knotted with basketball-sized light detectors. The water in each hole soon refreezes. The detectors are sensitive to blue light emitted in the surrounding clear ice. Such light is expected from ice collisions with high-energy neutrinos emitted by objects or explosions out in the universe. The above picture was taken looking down into the dee abyss. Instruments were lowered down past 2000 meters. Analyses of data from the AMANDA II detectors have recently been used to create the first map of the high-energy neutrino sky.

Island Universe, Cosmic Sand

Island Universe, Cosmic Sand



On August 13, 2002,while countin Perseid meteors unde dark, early morning Arizona skies,Rick Scott set out to photograph their fleetingbut fiery trails.The equipment he used included a telephoto lens and fastcolor film.After 21 pictures he'd caught only two meteors, but luckilythis was one of them.Tracking the sky, his ten minute long exposure shows afield of many stars in our own Milky Way galaxy, most toofaint to be seen by the unaided eye Flashingfrom lower left to upper right, the bright meteor wouldhave been an easy eyeful though,as friction with Earth's atmospher vaporized the hurtling grain o cosmic sand, a piece of dust from Come Swift-Tuttle.Just above and left of center, well beyond the stars ofthe Milky Way, lies the island universeknown as M31 or the Andromeda galaxy.The visible meteor trail begins about 100 kilometersabove Earth's surface, one of the closest celestial objectsseen in the sky.In contrast, Andromeda, about 2 million light-yearsaway, is the most distant object easily visible to the naked-eye.

Moons and Bright Mars

Moons and Bright Mars



In this serene view,the moons of Earth along withthe bright planet Mars shine abovethe city of Turku near the southwestern tip of Finland.Of course Earth's large natural satellite theMoon, at a distance of 400,000 kilometers,is by far the brightest object in this sky.But growing brighter an closer by the hour, Mars appears asthe impressively bright "star" at the right, about 64 millionkilometers from Turku.Streaking across the twilight sky between the two celestial beacons,Earth's largest artificial moon,the InternationalSpace Station,orbits about 400 kilometers above the planet's surface.To capture the moment, amateur astronome PetteriKankaro used a digital camera and combined exposures beginningat 23:34 Universal Time on July 17th.