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A different astronomy and space science related image is featured each day, along with a brief explanation.
Orion above Easter Island
Why were the statues on Easter Island built? No one is sure. What is sure is that over 800 large stone statues exist there. The Easter Island statues, stand, on the average, over twice as tall as a person and have over 200 times as much mass. Few specifics are known about the history or meaning of the unusual rock sculptures, but many believe that they were created about 700 years ago in the images of local leaders of a lost civilization. Featured here, one of the ancient Moai sculptures was imaged in 2016 before the constellation of Orion, including the famous line of three belt stars and brilliant stars Betelgeuse (far left in red) and Rigel (upper center). The stone giant appears, however, to be inspecting the brightest star in the night sky (far right): Sirius.
Flare Well AR2673
Almost out of view from our fair planet, rotating around the Sun's western edge giant active region AR2673 lashed out with another intense solar flare followed by a large coronal mass ejection on September 10. The flare itself is seen here at the right in an extreme ultraviolet image from the sun-staring Solar Dynamics Observatory. This intense flare was the fourth X-class flare from AR2673 this month. The active region's most recent associated coronal mass ejection collided with Earth's magnetosphere 2 days later. Say farewell to the mighty AR2673, for now. For the next two weeks, the powerful sunspot group will be on the Sun's far side.
The Climber and the Eclipse
What should you do if your rock climbing picture is photobombed by a total eclipse of the Sun? Rejoice -- because your planning paid off. After months of considering different venues, and a week of scouting different locations in Oregon's Smith Rock State Park, a group of photographers and rock climbers led by Ted Hesser, Martina Tibell, and Michael Shainblum settled on picturesque 100-meter tall Monkey Face tower as the dramatic foreground for their images of the pending total solar eclipse. Tension mounted as the eclipse time approached, planned juxtapositions were scrutinized, and the placement of rock climber Tommy Smith was adjusted. Right on schedule, though, the Moon moved in front of the Sun, and Smith moved in front of the Moon, just as planned. The solar eclipse image displayed here actually shows a diamond ring, an eclipse phase when a bit of the distant Sun is still visible beyond the Moon's surface.
A Waterspout in Florida
What's happening over the water? Pictured here is one of the better images yet recorded of a waterspout, a type of tornado that occurs over water. Waterspouts are spinning columns of rising moist air that typically form over warm water. Waterspouts can be as dangerous as tornadoes and can feature wind speeds over 200 kilometers per hour. Some waterspouts form away from thunderstorms and even during relatively fair weather. Waterspouts may be relatively transparent and initially visible only by an unusual pattern they create on the water. The featured image was taken in 2013 July near Tampa Bay, Florida. The Atlantic Ocean off the coast of Florida is arguably the most active area in the world for waterspouts, with hundreds forming each year. Some people speculate that waterspouts are responsible for some of the losses recorded in the Bermuda Triangle.
Lunar View, Solar Eclipse
Orbiting above the lunar nearside on August 21, the Lunar Reconnaissance Orbiter turned to look back on a bright, Full Earth. As anticipated its Narrow Angle Camera scanned this sharp view of our fair planet, catching the shadow of the Moon racing along a path across the United States at about 1,500 miles per hour. In fact, the dark lunar shadow is centered over Hopkinsville, Kentucky at 1:25:30 Central Daylight Time. From there, the New Moon blocked the Sun high in clear skies for about 2 minutes and 40 seconds in a total solar eclipse.
Saturn in Blue and Gold
Why is Saturn partly blue? The featured picture of Saturn approximates what a human would see if hovering close to the giant ringed world. The image was taken in 2006 March by the robot Cassini spacecraft now orbiting Saturn. Here Saturn's majestic rings appear directly only as a thin vertical line. The rings show their complex structure in the dark shadows they create on the image left. Saturn's fountain moon Enceladus, only about 500 kilometers across, is seen as the bump in the plane of the rings. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth's skies can appear blue -- molecules in the cloudless portions of both planet's atmospheres are better at scattering blue light than red. When looking deep into Saturn's clouds, however, the natural gold hue of Saturn's clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue -- one hypothesis holds that clouds are higher there. It is also not known why Saturn's clouds are colored gold. Next month, Cassini will end its mission with a final dramatic dive into Saturn's atmosphere.
The Heart Nebula in Hydrogen, Oxygen, and Sulfur
What powers the Heart Nebula? The large emission nebula dubbed IC 1805 looks, in whole, like a heart. The nebula's glow -- as well as the shape of the gas and dust clouds -- is powered by by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster Melotte 15. This deep telescopic image maps the pervasive light of narrow emission lines from atoms of hydrogen, oxygen, and sulfur in the nebula. The field of view spans just over two degrees on the sky, so that it appears larger than four times the diameter of a full moon. The cosmic heart is found in the constellation of Cassiopeia, the boastful mythical Queen of Aethiopia .
The Eagle and The Swan
The Eagle Nebula and the Swan Nebula span this broad starscape, a telescopic view toward the Sagittarius spiral arm and the center of our Milky Way galaxy. The Eagle, also known as M16, is at top and M17, the Swan, at bottom of the frame showing the cosmic clouds as brighter regions of active star-formation. They lie along the spiral arm suffused with reddish emission charactistic of atomic hydrogen gas, and dusty dark nebulae. M17, also called the Omega Nebula, is about 5500 light-years away, while M16 is some 6500 light-years distant. The center of both nebulae are locations of well-known close-up images of star formation from the Hubble Space Telescope. In this mosaic image that extends about 3 degrees across the sky, narrowband, high-resultion image data has been used to enhance the central regions of the Eagle and Swan. The extended wings of the Eagle Nebula spread almost 120 light-years. The Swan is over 30 light-years across.
A Total Solar Eclipse over Wyoming
Will the sky be clear enough to see the eclipse? This question was on the minds of many people attempting to view yesterday's solar eclipse. The path of total darkness crossed the mainland of the USA from coast to coast, from Oregon to South Carolina -- but a partial eclipse occurred above all of North America. Unfortunately, many locations saw predominantly clouds. One location that did not was a bank of Green River Lake, Wyoming. There, clouds blocked the Sun intermittantly up to one minute before totality. Parting clouds then moved far enough away to allow the center image of the featured composite sequence to be taken. This image shows the corona of the Sun extending out past the central dark Moon that blocks our familiar Sun. The surrounding images show the partial phases of the solar eclipse both before and after totality.
NGC 2442: Galaxy in Volans
Distorted galaxy NGC 2442 can be found in the southern constellation of the flying fish, (Piscis) Volans. Located about 50 million light-years away, the galaxy's two spiral arms extending from a pronounced central bar have a hook-like appearance in wide-field images. But this mosaicked close-up, constructed from Hubble Space Telescope and European Southern Observatory data, follows the galaxy's structure in amazing detail. Obscuring dust lanes, young blue star clusters and reddish star forming regions surround a core of yellowish light from an older population of stars. The sharp image data also reveal more distant background galaxies seen right through NGC 2442's star clusters and nebulae. The image spans about 75,000 light-years at the estimated distance of NGC 2442.
Stars, Gas, and Dust Battle in the Carina Nebula
Chaos reigns in the Carina Nebula where massive stars form and die. Striking and detailed, this close-up of a portion of the famous nebula is a combination of light emitted by hydrogen (shown in red) and oxygen (shown in blue). Dramatic dark dust knots and complex features revealed are sculpted by the winds and radiation of Carina's massive and energetic stars. One iconic feature of the Carina Nebula is the dark V-shaped dust lane that occurs in the top half of the image. The Carina Nebula spans about 200 light years, lies about 7,500 light years distant, and is visible with binoculars toward the southern constellation of Carina. In a billion years after the dust settles -- or is destroyed, and the gas dissipates -- or gravitationally condenses, then only the stars will remain -- but not even the brightest ones.
Night of the Perseids
This weekend, meteors will rain down near the peak of the annual Perseid Meteor Shower. Normally bright and colorful, the Perseid shower meteors are produced by dust swept up by planet Earth from the orbit of Comet Swift-Tuttle. They streak from a radiant in Perseus, above the horizon in clear predawn skies. Despite interfering light from August's waning gibbous moon, this year's Perseids will still be enjoyable, especially if you can find yourself in an open space, away from city lights, and in good company. Frames used in this composite view capture bright Perseid meteors from the 2016 meteor shower set against a starry background along the Milky Way, with even the faint Andromeda Galaxy just above center. In the foreground, astronomers of all ages have gathered on a hill above the Slovakian village of Vrchtepla.
Density Waves in Saturns Rings from Cassini
What causes the patterns in Saturn's rings? The Cassini spacecraft, soon ending its 13 years orbiting Saturn, has sent back another spectacular image of Saturn's immense ring system in unprecedented detail. The physical cause for some of Saturn's ring structures is not always understood. The cause for the beautifully geometric type of ring structure shown here in ring of Saturn, however, is surely a density wave. A small moon systematically perturbing the orbits of ring particles circling Saturn at slightly different distances causes such a density wave bunching. Also visible on the lower right of the image is a bending wave, a vertical wave in ring particles also caused by the gravity of a nearby moon. Cassini's final orbits are allowing a series of novel scientific measurements and images of the Solar System's most grand ring system.
Gravity s Grin
Albert Einstein's general theory of relativity, published over 100 years ago, predicted the phenomenon of gravitational lensing. And that's what gives these distant galaxies such a whimsical appearance, seen through the looking glass of X-ray and optical image data from the Chandra and Hubble space telescopes. Nicknamed the Cheshire Cat galaxy group, the group's two large elliptical galaxies are suggestively framed by arcs. The arcs are optical images of distant background galaxies lensed by the foreground group's total distribution of gravitational mass. Of course, that gravitational mass is dominated by dark matter. The two large elliptical "eye" galaxies represent the brightest members of their own galaxy groups which are merging. Their relative collisional speed of nearly 1,350 kilometers/second heats gas to millions of degrees producing the X-ray glow shown in purple hues. Curiouser about galaxy group mergers? The Cheshire Cat group grins in the constellation Ursa Major, some 4.6 billion light-years away.
Pelican Nebula Close Up
The prominent ridge of emission featured in this vivid skyscape is designated IC 5067. Part of a larger emission region with a distinctive shape, popularly called The Pelican Nebula, the ridge spans about 10 light-years and follows the curve of the cosmic pelican's head and neck. Fantastic, dark shapes inhabiting the view are clouds of cool gas and dust sculpted by energetic radiation from young, hot, massive stars. But stars are also forming within the dark shapes. Twin jets emerging from the tip of the long, dark tendril left of center are the telltale signs of an embedded protostar cataloged as Herbig-Haro 555 (HH 555). In fact, other Herbig-Haro objects indicating the presence of protostars are found within the frame. The Pelican Nebula itself, also known as IC 5070, is about 2,000 light-years away. To find it, look northeast of bright star Deneb in the high flying constellation Cygnus.
Bright Spiral Galaxy M81
One of the brightest galaxies in planet Earth's sky is similar in size to our Milky Way Galaxy: big, beautiful M81. This grand spiral galaxy can be found toward the northern constellation of the Great Bear (Ursa Major). This superbly detailed view reveals M81's bright yellow nucleus, blue spiral arms, and sweeping cosmic dust lanes with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust lane actually runs straight through the disk, to the left of the galactic center, contrary to M81's other prominent spiral features. The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82. Scrutiny of variable stars in M81 has yielded one of the best determined distances for an external galaxy -- 11.8 million light-years.
The Great Gig in the Sky
There were no crowds on the beach at Phillips Lake, Oregon on August 21. But a few had come there to stand, for a moment, in the dark shadow of the Moon. From the beach, this unscripted mosaic photo records their much anticipated solar eclipse. In two vertical panels it catches the last few seconds of totality and the first instant of 3rd contact, just as the eclipse ends and sunlight faintly returns. Across the US those gathered along the path of totality also took pictures and shared their moment. And like those at Phillips Lake they may treasure the experience more than any planned or unplanned photograph of the total eclipse of the Sun.
Saturns Rings from the Inside Out
What do Saturn's rings look like from Saturn? Images from the robotic spacecraft Cassini are providing humanity with this unprecedented vantage point as it nears the completion of its mission. Previous to Cassini's Grand Finale orbits, all images of Saturn's majestic ring system were taken from outside of the rings looking in. Pictured in the inset is the remarkable video, while the spacecraft's positions are depicted in the surrounding animation. Details of the complex rings are evident as the short time-lapse sequence begins, while the paper-thin thickness of the rings becomes apparent near the video's end. The featured images were taken on August 20. Cassini has only a few more orbits around Saturn left before it is directed to dive into the giant planet on September 15.
A First Glimpse of the Great American Eclipse
Making landfall in Oregon, the Moon's dark umbral shadow toured the United States on August 21. Those gathered along its coast to coast path were witness to a total eclipse of the Sun, possibly the most widely shared celestial event in history. But first, the Moon's shadow touched the northern Pacific and raced eastward toward land. This dramatic snapshot was taken while crossing the shadow path 250 miles off the Oregon coast, 45,000 feet above the cloudy northern Pacific. Though from a shorter totality, it captures the eclipse before it could be seen from the US mainland. With the eclipsed Sun not far above, beautiful colors appear along the western horizon giving way to a clear, pitch-black, stratospheric sky in the shadow of the Moon.
Panoramic Eclipse Composite with Star Trails
What was happening in the sky during last week's total solar eclipse? This featured little-planet, all-sky, double time-lapse, digitally-fused composite captured celestial action during both night and day from a single location. In this 360x180 panorama, north and south are at the image bottom and top, while east and west are at the left and right edges, respectively. During four hours the night before the eclipse, star trails were captured circling the north celestial pole (bottom) as the Earth spun. During the day of the total eclipse, the Sun was captured every fifteen minutes from sunrise to sunset (top), sometimes in partial eclipse. All of these images were then digitally merged onto a single image taken exactly during the total solar eclipse. Then, the Sun's bright corona could be seen flaring around the dark new Moon (upper left), while Venus simultaneously became easily visible (top). The tree in the middle, below the camera, is a Douglas fir. The images were taken with care and planning at Magone Lake in Oregon, USA.
A Fleeting Double Eclipse of the Sun
Last week, for a fraction of a second, the Sun was eclipsed twice. One week ago today, many people in North America were treated to a standard, single, partial solar eclipse. Fewer people, all congregated along a narrow path, experienced the eerie daytime darkness of a total solar eclipse. A dedicated few with fast enough camera equipment, however, were able to capture a double eclipse -- a simultaneous partial eclipse of the Sun by both the Moon and the International Space Station (ISS). The Earth-orbiting ISS crossed the Sun in less than a second, but to keep the ISS from appearing blurry, exposure times must be less than 1/1000th of a second. The featured image composite captured the ISS multiple times in succession as it zipped across the face of the Sun. The picture was taken in a specific color emitted by hydrogen which highlights the Sun's chromosphere, a layer hotter and higher up than the usually photographed photosphere.
Diamond Ring in a Cloudy Sky
As the Moon's shadow swept across the US on August 21, eclipse chasers in the narrow path of totality were treated to a diamond ring in the sky. At the beginning and end of totality, the fleeting and beautiful effect often produces audible gasps from an amazed audience. It occurs just before or after the appearance of the faint solar corona with a brief ring of light and glimpse of Sun. In this scene from the end of totality at Central, South Carolina, clouds drift near the Sun's diamond ring in the sky.
The Crown of the Sun
During a total solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. Streamers and shimmering features visible to the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single photograph. But this composite of telescopic images covers a wide range of exposure times to reveal the crown of the Sun in all its glory. The aligned and stacked digital frames were taken in clear skies above Stanley, Idaho in the Sawtooth Mountains during the Sun's total eclipse on August 21. A pinkish solar prominence extends just beyond the right edge of the solar disk. Even small details on the dark night side of the New Moon can be made out, illuminated by sunlight reflected from a Full Earth.
Milky Way over Chilean Volcanoes
Sometimes, the sky mimics the ground. Taken in 2017 May from the Atacama Desert in Chile, the foreground of the featured image encompasses the dipping edge of the caldera of an extinct volcano. Poetically echoing the dip below is the arch of our Milky Way Galaxy above. Many famous icons dot this southern nighttime vista, including the center of our Milky Way Galaxy on the far left, the bright orange star Antares also on the left, the constellation of the Southern Cross near the top of the arch, and the red-glowing Gum Nebula on the far right. Just above the horizon and splitting two distant volcanic peaks near the image center is the Large Magellanic Cloud -- the largest satellite galaxy of the Milky Way.
Perseid by the Sea
Just after moonrise on August 12 this grain of cosmic sand fell by the sea, its momentary flash part of the annual Perseid Meteor Shower. To create the Perseid meteors, dust along the orbit of periodic comet Swift-Tuttle is swept up by planet Earth. The cometary debris plows through the atmosphere at nearly 60 kilometers per second and is quickly vaporized at altitudes of 100 kilometers or so. Perseid meteors are often bright and colorful, like the one captured in this sea and night skyscape. Against starry sky and faint Milky Way the serene view looks south and west across the Adriatic Sea, from the moonlit Dalmatian coast toward the island of Brac.
A Total Solar Eclipse of Saros 145
A darkened sky holds bright planet Venus, the New Moon in silhouette, and the shimmering corona of the Sun in this image of a total solar eclipse. A composite of simultaneous telephoto and wide angle frames it was taken in the path of totality 18 years ago, August 11, 1999, near Kastamonu, Turkey. That particular solar eclipse is a member of Saros 145. Known historically from observations of the Moon's orbit, the Saros cycle predicts when the Sun, Earth, and Moon will return to the same geometry for a solar (or lunar) eclipse. The Saros has a period of 18 years, 11 and 1/3 days. Eclipses separated by one Saros period belong to the same numbered Saros series and are very similar. But the path of totality for consecutive solar eclipses in the same Saros shifts across the Earth because the planet rotates for an additional 8 hours during the cycle's fractional day. So the next solar eclipse of Saros 145 will also be a total eclipse, and the narrow path of totality will track coast to coast across the United States on August 21, 2017.
August Lunar Eclipse
August's Full Moon is framed in this sharp, high dynamic range composition. Captured before sunrise on August 8 from Sydney, Australia, south is up and the Earth's dark, umbral shadow is at the left, near the maximum phase of a partial lunar eclipse. Kicking off the eclipse season, this time the Full Moon's grazing slide through Earth's shadow was visible from the eastern hemisphere. Up next is the much anticipated total solar eclipse of August 21. Then, the New Moon's shadow track will include North America, the narrow path of totality running coast to coast through the United States.
Spiral Galaxy NGC 1512: The Inner Ring
Most galaxies don't have any rings -- why does this galaxy have two? To begin, the bright band near NGC 1512's center is a nuclear ring, a ring that surrounds the galaxy center and glows brightly with recently formed stars. Most stars and accompanying gas and dust, however, orbit the galactic center in a ring much further out -- here seen near the image edge. This ring is called, counter-intuitively, the inner ring. If you look closely, you will see this the inner ring connects ends of a diffuse central bar that runs horizontally across the galaxy. These ring structures are thought to be caused by NGC 1512's own asymmetries in a drawn-out process called secular evolution. The gravity of these galaxy asymmetries, including the bar of stars, cause gas and dust to fall from the inner ring to the nuclear ring, enhancing this ring's rate of star formation. Some spiral galaxies also have a third ring -- an outer ring that circles the galaxy even further out.
North North Temperate Zone Little Red Spot
On July 11, the Juno spacecraft once again swung near the turbulent Jovian cloud tops. On its seventh orbital closest approach this perijove passage brought Juno within 3,500 kilometers of the Solar System's largest planetary atmosphere. Near perijove the rotating JunoCam was able to record this stunning, clear view of one of Jupiter's signature vortices. About 8,000 kilometers in diameter, the anticyclonic storm system was spotted in Jupiter's North North Temperate Zone in the 1990s. That makes it about half the size of an older and better known Jovian anticyclone, the Great Red Spot, but only a little smaller than planet Earth. At times taking on reddish hues, the enormous storm system is fondly known as a North North Temperate Zone Little Red Spot.
The Dust Monster in IC 1396
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 featured 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.
