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Layers of Red Cliffs on Mars Credit: HiRISE, MRO, LPL (U. Arizona), NASA Explanation: How did these layers of red cliffs form on Mars? No one is sure. The northern ice cap on Mars is nearly divided into two by a huge division named Chasma Boreale. No similar formation occurs on Earth. Pictured above, several dusty layers leading into this deep chasm are visible. Cliff faces, mostly facing left but still partly visible from above, appear dramatically red. The light areas are likely water ice. The above image spans about one kilometer near the north of Mars, and the elevation...

Earth at Night C. Mayhew & R. Simmon (NASA/GSFC), NOAA/NGDC, DMSP Digital Archive Explanation: This is what the Earth looks like at night. Can you find your favorite country or city? Surprisingly, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts of South America, Africa, Asia, and Australia. The above image is actually...

Solar Prominence Unfurls Credit: STEREO Project, NASA Explanation: On September 29, this magnificent eruptive solar prominence lifted away from the Sun's surface, unfurling into space over the course of several hours. Suspended in twisted magnetic fields, the hot plasma structure is many times the size of planet Earth and was captured in this view by the Sun-watching STEREO (Ahead) spacecraft. The image was recorded in extreme ultraviolet light emitted by ionized Helium, an element originally identified in the solar spectrum. Seen against the brilliant solar surface in visible light, such prominences appear as dark filaments because they are relatively...

Young Suns of NGC 7129 Credit & Copyright: Bob and Janice Fera (Fera Photography) Explanation: Young suns still lie within dusty NGC 7129, some 3,000 light-years away toward the royal constellation Cepheus. While these stars are at a relatively tender age, only about a million years old, it is likely that our own Sun formed in a similar stellar nursery some five billion years ago. Most noticeable in the striking image are the lovely bluish dust clouds that reflect the youthful starlight, but the smaller, deep red crescent shapes are also markers of energetic, young stellar objects. Known as Herbig-Haro...

NGC 253 Close-Up Credit: NASA, ESA, J. Dalcanton, B. Williams (Univ. Washington) Ground-based data: T. Rector (Univ. Alaska, Anchorage), T. Abbott, NOAO/AURA/NSF Explanation: This dusty island universe is one of the brightest spiral galaxies in the sky. Seen nearly edge-on, NGC 253 lies a mere 13 million light-years away and is the largest member of the Sculptor Group of galaxies, neighbor to our own local galaxy group. The remarkably sharp, close-up view is based on data from the Hubble's Advanced Camera for Surveys (ACS). Beginning on the left near the galaxy's core, the panorama follows filaments of dust, interstellar gas,...

The First Rocket Launch from Cape Canaveral Credit: GRIN, NASA Explanation: A new chapter in space flight began on 1950 July with the launch of the first rocket from Cape Canaveral, Florida: the Bumper 2. Shown above, the Bumper 2 was an ambitious two-stage rocket program that topped a V-2 missile base with a WAC Corporal rocket. The upper stage was able to reach then-record altitudes of almost 400 kilometers, higher than even modern Space Shuttles fly today. Launched under the direction of the General Electric Company, the Bumper 2 was used primarily for testing rocket systems and for research...

True Image from False Kiva Credit & Copyright: Wally Pacholka (Astropics.com/TWAN) Explanation: Is there any place in the world you could see a real sight like this? Yes. Pictured above is single exposure image spectacular near, far, and in between. Diving into the Earth far in the distance is part of the central band of our Milky Way Galaxy, taken with a long duration exposure. Much closer, the planet Jupiter is visible as the bright point just to band's left. Closer still are picturesque buttes and mesas of the Canyonlands National Park in Utah, USA, lit by a crescent...

Explanation: Is there any place in the world you could see a real sight like this? Yes. Pictured above is single exposure image spectacular near, far, and in between. Diving into the Earth far in the distance is part of the central band of our Milky Way Galaxy, taken with a long duration exposure. Much closer, the planet Jupiter is visible as the bright point just to band's left. Closer still are picturesque buttes and mesas of the Canyonlands National Park in Utah, USA, lit by a crescent moon. In the foreground is a cave housing a stone circle...

Young Stars of NGC 346 Credit: Antonella Nota (ESA/STScI) et al., ESA, NASA Explanation: The massive stars of NGC 346 are short lived, but very energetic. The star cluster is embedded in the largest star forming region in the Small Magellanic Cloud, some 210,000 light-years distant. Their winds and radiation sweep out an interstellar cavern in the gas and dust cloud about 200 light-years across, triggering star formation and sculpting the region's dense inner edge. Cataloged as N66, the star forming region also appears to contain a large population of infant stars. A mere 3 to 5 million years old...

M83: The Thousand-Ruby Galaxy Color Composite: Davide De Martin (Skyfactory)Credit: European Southern Observatory Science Archive Explanation: Big, bright, and beautiful, spiral galaxy M83 lies a mere twelve million light-years away, near the southeastern tip of the very long constellation Hydra. Prominent spiral arms traced by dark dust lanes and blue star clusters lend this galaxy its popular name of the Southern Pinwheel. But reddish star forming regions that dot the sweeping arms highlighted in this sparkling color composite also suggest another nickname, The Thousand-Ruby Galaxy. About 40,000 light-years across, M83 is a member of a group of galaxies that...

Companion of a Young, Sun-like Star Credit: Gemini Observatory, D. Lafreniere, R. Jayawardhana, M. van Kerkwijk (Univ. Toronto) Explanation: Located just 500 light-years away toward the constellation Scorpius, this star is only slightly less massive and a little cooler than the Sun. But it is much younger, a few million years old compared to the middle-aged Sun's 5 billion years. This sharp infrared image shows the young star has a likely companion positioned above and left - a hot planet with about 8 times the mass of Jupiter, orbiting a whopping 330 times the Earth-Sun distance from its parent star....

Exploring the Ring Credit & Copyright: Astro-Cooperation - Stefan Heutz/Wolfgang Ries Explanation: A familiar sight for northern hemisphere astronomers, the Ring Nebula (M57) is some 2,000 light-years away in the musical constellation Lyra. The central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from two different telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from a...

SN 1006: A Supernova Ribbon from Hubble Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Acknowledgement: W. Blair et al. (JHU) Explanation: What created this unusual space ribbon? Most assuredly, one of the most violent explosions ever witnessed by ancient humans. Back in the year 1006 AD, light reached Earth from a stellar explosion in the constellation of the Wolf (Lupus), creating a "guest star" in the sky that appeared brighter than Venus and lasted for over two years. The supernova, now cataloged at SN 1006, occurred about 7,000 light years away and has left a large remnant that continues to expand...

The Heart and Soul Nebulas Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator;Color Composite: Davide De Martin (Skyfactory) Explanation: 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 in the above zoomable view 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...

M33: Triangulum Galaxy Credit & Copyright: Paul Mortfield, Stefano Cancelli Explanation: The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for...

Planets over Perth Credit & Copyright: John Goldsmith, Celestial Visions exhibition, TWAN Explanation: A bright trio of terrestrial planets was joined by a young Moon on September 1st, in planet Earth's early evening skies. In this view of the celestial gathering from Perth, Western Australia, the Moon's sunlit crescent is nearly horizontal at Perth's southern latitude of about 32 degrees. Venus, then Mercury, and finally Mars shine above colorful city lights on the far shore of the Swan River. The six unlit towers on the left surround a large cricket stadium. For now, the planetary trio still lingers low in...

Mountain Top Meteors Credit & Copyright: Alex Tudorica, Romanian Society for Meteors and Astronomy Faculty of Physics, Bucharest University Explanation: A mountain top above the clouds and light-polluted cities was a good place to go to watch this August's Perseid meteor shower. In fact, this composite picture from one of the highest points in Romania, the Omu summit (2,507 meters) in the Southern Carpathian Mountains, captures about 20 of the shower's bright streaks against a starry night sky. The cosmic debris stream that creates the shower is composed of dust particles moving along parallel paths, following the orbit of their...

The Anthe Arc around Saturn Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: What created this unusual partial ring around Saturn? Discovered last year, the arc was captured in clear detail only two months ago by the Saturn-orbiting Cassini spacecraft. Since the arc occupies the same orbit as the small moon Anthe, a leading hypothesis holds that the arc was created by, and is replenished by, meteor impacts on Anthe. Similar arcs have been previously discovered, including an arc associated with the small Saturnian moon Methone, one arc related to Saturn's G ring, and several arcs orbiting Neptune. Pictured...

M110: Satellite of the Andromeda Galaxy Credit & Copyright: Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum Astronomia), Hawaiian Starlight Explanation: Our Milky Way Galaxy is not alone. It is part of a gathering of about 25 galaxies known as the Local Group. Members include the Great Andromeda Galaxy (M31), M32, M33, the Large Magellanic Cloud, the Small Magellanic Cloud, Dwingeloo 1, several small irregular galaxies, and many dwarf elliptical and dwarf spheroidal galaxies. Pictured on the lower right is one of the dwarf ellipticals: NGC 205. Like M32, NGC 205 is a companion to the large M31, and can sometimes...

Rosetta Spacecraft Passes Asteroid SteinsCredit & Copyright: Rosetta Team, ESA Explanation: What's that diamond in the sky? Cruising though space, sometimes you'll come across an unusual object. Such was the case on Friday for ESA's Rosetta spacecraft on its way to comet Churyumov-Gerasimenko in 2014. Robotic Rosetta buzzed right by the main belt asteroid 2867 Šteins, taking many pictures, some of which have been compiled into a short video. At first glance, Steins looked like a 5-kilometer wide diamond, but as Rosetta shot by, craters and a more extended shape become evident. In the above sequence of six images, a...

Milky Way Road Trip Credit & Copyright: Tunç Tezel (TWAN) Explanation: In search of planets and the summer Milky Way, astronomer Tunç Tezel took an evening road trip. Last Saturday, after driving the winding road up Uludag, a mountain near Bursa, Turkey, he was rewarded by this beautiful skyview to the south. Near the center, bright planet Jupiter outshines the city lights below and the stars of the constellation Sagittarius. Above the mountain peaks, an arcing cloud bank seems to lead to the Milky Way's own cloudy apparition plunging into the distant horizon. In Turkish, Uludag means Great Mountain. Uludag...

Spokes in the Helix Nebula Credit & Copyright: Don Goldman, Sierra Remote Observatories Explanation: At first glance, the Helix Nebula (aka NGC 7293), looks simple and round. But this well-studied example of a planetary nebula, produced near the end of the life of a sun-like star, is now understood to have a surprisingly complex geometry. Its extended loops and comet-shaped features have been explored in Hubble Space Telescope images. Still, a 16-inch diameter telescope and camera with broad and narrow band filters was used to create this sharp view of the Helix. The color composite also reveals the nebula's...

31 Million Miles from Planet Earth Video Credit: Donald J. Lindler, Sigma Space Corporation, GSFC, Univ. Maryland, EPOCh/DIXI Science Teams Explanation: On July 4th, 2005, the Deep Impact spacecraft directed a probe to impact the nucleus of Comet Tempel 1. Still cruising through the solar system, earlier this year the robotic spacecraft looked back to record a series of images of its home world 31 million miles (50 million kilometers) away. In a sequence from top left to bottom right, these four frames from the video show a rotating Earth. They combine visible and near-infrared image data with enough resolution...

NGC 1316: After Galaxies Collide Credit & Copyright: Martin Pugh Explanation: Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Their investigation indicates that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just above it. Supporting evidence includes the dark dust lanes characteristic of a spiral galaxy, and faint swirls of stars and gas visible in this wide and deep image. What remains unexplained are the unusually small globular star clusters, seen as faint dots on the image....

CG4: A Ruptured Cometary Globule Credit & Copyright: Mike Sidonio Explanation: Can a gas cloud grab a galaxy? It's not even close. The "claw" of this odd looking "creature" in the above photo is a gas cloud known as a cometary globule. This globule, however, has ruptured. Cometary globules are typically characterized by dusty heads and elongated tails. These features cause cometary globules to have visual similarities to comets, but in reality they are very much different. Globules are frequently the birthplaces of stars, and many show very young stars in their heads. The reason for the rupture in the...

Eclipse over the Great Wall Credit & Copyright: Mike Simmons (Astronomers Without Borders, TWAN) Explanation: Contrary to the famous myth, you can't see the Great Wall of China from the Moon ... even during a total solar eclipse. But on August 1 you could see the Moon eclipsing the Sun from the Great Wall. In fact, from this location near the Great Wall's western end, the Moon completely blocked the Sun's overwhelming disk revealing a shimmering solar corona and bright planets in the briefly darkened sky. A main pass, The Great Wall's Jiayuguan Fort, is also silhouetted in the...

Generations of Stars in W5 Credit: Lori Allen, Xavier Koenig (Harvard-Smithsonian CfA) et al., JPL-Caltech, NASA Explanation: Giant star forming region W5 is over 200 light-years across and about 6,500 light-years away in the constellation Cassiopeia. W5's sculpted clouds of cold gas and dust seem to form fantastic shapes in this impressive mosaic of infrared images from the Spitzer Space Telescope. In fact, the area on the right includes the structures previously dubbed the Mountains of Creation. New evidence indicates that successive generations of stars formed in the W5 region in an expanding pattern of triggered star formation. The older,...

Fermi's First Light Credit: NASA, DOE, International LAT Team Explanation: Launched on June 11 to explore the universe at extreme energies, the Gamma-ray Large Area Space Telescope has been officially renamed the Fermi Gamma-ray Space Telescope, in honor of Nobel Laureate Enrico Fermi (1901-1954), pioneer in high-energy physics. After testing, Fermi's two instruments, the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope (LAT), are now regularly returning data. Fermi's first map of the gamma-ray sky from the LAT is shown in this false-color image, an all-sky view that looks toward the center of our Milky Way Galaxy with the...

IC 5146: The Cocoon Nebula Credit & Copyright: Ken Crawford (Rancho Del Sol Observatory) Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide, located some 4,000 light years away toward the northern constellation Cygnus. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula is likely only a few hundred thousand years old,...

Grand Spiral Galaxy NGC 1232 Credit: FORS1, 8.2-meter VLT Antu, ESO Explanation: Galaxies are fascinating not only for what is visible, but for what is invisible. Grand spiral galaxy NGC 1232, captured in detail by one of the new Very Large Telescopes, is a good example. The visible is dominated by millions of bright stars and dark dust, caught up in a gravitational swirl of spiral arms rotating about the center. Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them. Less visible,...

Regular ImageMouse - over ImageActive Galaxy NGC 1275 Credit: NASA, ESA, Hubble Heritage (STScI/AURA); A. Fabian (IoA, Cambridge U.), L. Frattare (STScI), CXC, G. Taylor, NRAO,VLA Explanation: Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. A prodigious source of x-rays and radio emission, NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy's core. This stunning visible light image from the Hubble Space Telescope shows galactic debris and filaments of glowing gas, some up to 20,000 light-years long. The filaments...

NGC 6960: The Witch's Broom Nebula Credit & Copyright: Adam Block, Mount Lemmon SkyCenter, Univ. Arizona Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star and record the colorful expanding cloud as the Veil Nebula. Pictured above is the west end of the Veil Nebula known technically as NGC 6960 but less formally as the Witch's Broom Nebula. The expanding debris cloud gains its colors by sweeping up and exciting existing...

Baily's Beads near Solar Eclipse Totality Credit & Copyright: Leonid Durman Explanation: Just before the Sun blacks out, something strange occurs. As the Moon moves to completely cover the Sun in a total solar eclipse, beads of bright sunlight stream around the edge of the Moon. This effect, known as Baily's beads, is named after Francis Baily who called attention to the phenomenon in 1836. Although, the number and brightness of Baily's beads used to be unpredictable, today the Moon is so well mapped that general features regarding Baily's beads are expected. When a single bead dominates, it is...

Io's Surface: Under Construction Credit: Galileo Project, JPL, NASA Explanation: Like the downtown area of your favorite city, the roads you drive to work on, and any self-respecting web site ... Io's surface is constantly under construction. This moon of Jupiter holds the distinction of being the Solar System's most volcanically active body -- its bizarre looking surface continuously formed and reformed by lava flows. Generated using 1996 data from NASA's Galileo spacecraft, this high resolution composite image is centered on the side of Io that always faces away from Jupiter. It has been enhanced to emphasize Io's surface brightness...

CopyrightedFacing NGC 6946 Credit & Copyright: Volker Wendel (Spiegelteam) Explanation: From our vantage point in the Milky Way Galaxy, we see NGC 6946 face-on. The big, beautiful spiral galaxy is located just 10 million light-years away, behind a veil of foreground dust and stars in the high and far-off constellation of Cepheus. From the core outward, the galaxy's colors change from the yellowish light of old stars in the center to young blue star clusters and reddish star forming regions along the loose, fragmented spiral arms. NGC 6946 is also bright in infrared light and rich in gas and dust,...

Perseid Trail Credit & Copyright: Wally Pacholka (Astropics.com / TWAN) Explanation: This bright and colorful meteor flashed through Tuesday's early morning skies, part of the annual Perseid Meteor Shower. The lovely image is one of over 350 frames captured on August 12 from the Joshua Tree National Park, in California, USA . Dust from comet Swift-Tuttle is responsible for the Perseids, creating the northern hemisphere's regular summer sky show. The comet dust is vaporized as it enters the atmosphere at upwards of 60 kilometers per second, producing visible trails that begin at altitudes of around 100 kilometers. Of course, the...

NGC 6888: The Crescent Nebula Credit & Copyright: Tony Hallas Explanation: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This beautiful telescopic view combines a composite color image with narrow band data that isolates light from hydrogen and oxygen atoms in the wind-blown nebula. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar...

Black Hole Candidate Cygnus X-1 Credit: ESA, Hubble Explanation: Is that a black hole? Quite possibly. The Cygnus X-1 binary star system contains one of the best candidates for a black hole. The system was discovered because it is one of the brightest X-ray sources on the sky, shining so bright it was detected by the earliest rockets carrying cameras capable of seeing the previously unknown X-ray sky. The star's very name indicates that it is the single brightest X-ray source in the constellation of the Swan Cygnus. Data indicate that a compact object there contains about nine times...

Aurora Persei Credit & Copyright: Jimmy Westlake (Colorado Mountain College) Explanation: Dark skies are favored for viewing meteor showers -- so the best viewing of this year's Perseids will occur in the early morning. While the Perseid meteor shower is scheduled to peak over the next few days, bright light from a gibbous Moon will also flood the early evening and mask the majority of relatively faint meteors. Still, skygazing in the early morning after the Moon sets (after about 2 AM local time) could reveal spectacular earthgrazing meteors. Persisting observing at any time after sunset can reward northern...

The Crown of the Sun Credit & Copyright: Hartwig Luethen Explanation: During a total solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. The subtle shades and shimmering features of the corona that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single picture. But this composite of 28 digital images ranging in exposure time from 1/1000 to 2 seconds comes close to revealing the crown of the Sun in all its glory. The telescopic views were recorded near Kochenevo, Russia during the August...

At the Sun's Edge Credit & Copyright: Catalin Beldea (Descopera Magazine) Explanation: A train trip on the Trans-Siberian railway to Novosibirsk resulted in this stunning view along the edge of the Sun recorded during the August 1st total solar eclipse. The picture is a composite of two images taken at special moments in the eclipse sequence, corresponding to the very beginning and the very end of the total eclipse phase. Those times are known to eclipse chasers as 2nd and 3rd contact. Bright beads around the Moon's dark silhouette are rays of sunlight shining through lunar valleys at the edge...

NGC 1818: A Young Globular Cluster Credit: Diedre Hunter (Lowell Obs.) et al., HST, NASA Explanation: Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are perhaps 200 left. Many globular clusters were destroyed over the eons by repeated fateful encounters with each other or the Galactic center. Surviving relics are older than any Earth fossil, older than any other structures in our Galaxy, and limit the universe itself in raw age. There are few, if any, young globular clusters in...

X-Rays from the Cat's Eye Nebula Credit: X-ray: NASA/CXC/SAO; Optical: NASA/STScI Explanation: Haunting patterns within planetary nebula NGC 6543 readily suggest its popular moniker -- the Cat's Eye nebula. Starting in 1995, stunning false-color optical images from the Hubble Space Telescope detailed the swirls of this glowing nebula, known to be the gaseous shroud expelled from a dying sun-like star about 3,000 light-years from Earth. This composite picture combines the latest Hubble optical image of the Cat's Eye with new x-ray data from the orbiting Chandra Observatory and reveals surprisingly intense x-ray emission indicating the presence of extremely hot gas....

Open Cluster NGC 290: A Stellar Jewel Box Credit: ESA & NASA; Acknowledgement: E. Olszewski (U. Arizona) Explanation: Jewels don't shine this bright -- only stars do. Like gems in a jewel box, though, the stars of open cluster NGC 290 glitter in a beautiful display of brightness and color. The photogenic cluster, pictured above, was captured recently by the orbiting Hubble Space Telescope. Open clusters of stars are younger, contain few stars, and contain a much higher fraction of blue stars than do globular clusters of stars. NGC 290 lies about 200,000 light-years distant in a neighboring galaxy...

Eclipse Shirt Credit & Copyright: Philippe Haake Explanation: Of course, everyone is concerned about what to wear to a solar eclipse. No need to worry though, nature often conspires to project images of the eclipse so that stylish and appropriate patterns adorn many visible surfaces - including clothing - at just the right time. Most commonly, small gaps between leaves on trees can act as pinhole cameras and generate multiple recognizable images of the eclipse. In Madrid to view the 2005 October 3rd annular eclipse of the Sun, astronomer Philippe Haake met a friend who had another inspiration. The result,...

Moon Games Credit & Copyright: Laurent Laveder (PixHeaven.net / TWAN) Explanation: The Moon's measured diameter is around 3,476 kilometers (2,160 miles). But apparent angular size, or the angle covered by an object, can also be important to Moon enthusiasts. Angular size depends on distance, the farther away an object is, the smaller an angle it covers. Since the Moon is 400,000 kilometers away, its angular size is only about 1/2 degree, a span easily covered by the tip of your finger held at arms length, or a measuring tape held in the distance by a friend. Of course the Sun...

Galaxies on a String Credit & Copyright: Acquisition - Martin Winder, Processing - Warren Keller Galaxies NGC 5216 (top right) and NGC 5218 really do look like they are connected by a string. Of course, that string is a cosmic trail of gas, dust, and stars about 22,000 light-years long. Also known as Keenan's system (for its discoverer) and Arp 104, the interacting galaxy pair is some 17 million light-years away in the constellation Ursa Major. The debris trail that joins them, along with NGC 5218's comma-shaped extension and the distorted arms of NGC 5216 are a consequence of mutual...

The Milky Way Over Ontario Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography) Explanation: Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month over Ontario, Canada, when part of a spectacular sky also became visible in a reflection off a lake. To start, the brightest objects visible are bright stars and the planet Jupiter, seen as the brightest spot on the upper left. A distant town appears as a diffuse glow over the horizon. More faint still, the disk of the Milky Way Galaxy becomes apparent as...

SDSSJ1430: A Galaxy Einstein Ring Credit: A. Bolton (UH/IfA) for SLACS and NASA/ESA Explanation: What's large and blue and can wrap itself around an entire galaxy? A gravitational lens mirage. Pictured above on the left, the gravity of a normal white galaxy has gravitationally distorted the light from a much more distant blue galaxy. More normally, such light bending results in two discernable images of the distant galaxy, but here the lens alignment is so precise that the background galaxy is distorted into a nearly complete ring. Since such a lensing effect was generally predicted in some detail by Albert...

IC 4406: A Seemingly Square Nebula Credit: C. R. O'Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA Explanation: How can a round star make a square nebula? This conundrum comes to light when studying planetary nebulae like IC 4406. Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula. This representative-color picture is a composite made by combining images taken by the Hubble Space Telescope...