NASA Astronomy Picture of the Day 2016-9

Light at the End of the Road

The bright light at the end of this country road is actually a remarkably close conjunction of two planets. After sunset on August 27 brilliant Venus and Jupiter almost appear as a single celestial beacon in the night skyscape taken near Lake Wivenhoe, Queensland, Australia. A spectacular vertical panorama from the southern hemisphere, it shows the central Milky Way near zenith, posed on top of a pillar of Zodiacal light along the ecliptic plane. Of course Mars and Saturn are near the ecliptic too, just below the galaxy's central bulge. Above and left of a tree on the horizon, fleeting planet Mercury also adds to the light at the end of the road.

Little Planet Astro Camp

Day and night on this little planet look a lot like day and night on planet Earth. In fact, the images used to construct the little planet projection, a digitally warped and stitched mosaic covering 360x180 degrees, were taken during day and night near Tarján, Hungary, planet Earth. They span a successful 33-hour-long photo experiment at July's Hungarian Astronomical Association Astro Camp. The time-series composite follows the solar disk in 20 minute intervals from sunrise to sunset and over six hours of star trails in the northern night sky centered on the North Celestial Pole near bright star Polaris. The orbiting International Space Station traced the offset arc across the northern night. Below the little planet's nightside horizon, red light lamps of fellow astro-campers left the night-long, dancing trails.

Reunion Island Eclipse

The New Moon's dark shadow crossed planet Earth on September 1. In silhouette the Moon didn't quite cover the Sun though, creating an an annular solar eclipse. The shadow's narrow central path was about 100 kilometers wide at maximum eclipse. Beginning in the South Atlantic, it tracked toward the east across Africa, ending in the Indian Ocean. Waiting on the Indian Ocean's Reunion Island, eclipse watchers enjoyed a view just north of the eclipse centerline, the annular phase lasting a few minutes or less. Clouds threaten the nearly eclipsed Sun but create a dramatic sky in this wide-angle and telephoto composite at a partial phase from the northern side of the 50 kilometer wide island.

Io over Jupiter from Voyager 1

Back in 1979, NASA's Voyager 1 spacecraft flew past Jupiter and its moons. The images in this mosaic, featuring the moon Io against a background of gas giant Jupiter's diffuse swirling cloud bands, were recorded by Voyager's camera from a distance of about 8.3 million kilometers. The Io image from this mosaic may be the first to show curious round features on Io's surface with dark centers and bright rims more than 60 kilometers across. Now known to be volcanic in origin, these features were then thought likely to be impact craters, commonly seen on rocky bodies throughout the Solar System. But as Voyager continued to approach Io, close-up pictures revealed a bizarre world devoid of impact craters, frequently resurfaced by volcanic activity. Earlier this year a new robotic spacecraft, NASA's Juno, began to orbit Jupiter and last week made a pass within 5,000 kilometers of Jupiter's clouds. During the next two years, it is hoped that Juno will discover new things about Jupiter, for example what's in Jupiter's core. Free Download: APOD 2017 Calendar: NASA Images

Spiral Meteor through the Heart Nebula

What is this meteor doing? Dynamically, the unusually short and asymmetric train may indicate that the sand-sized grain at the center of the glow is momentarily spinning as it ablates, causing its path to be slightly spiral. Geographically, the meteor appears to be going through the Heart Nebula, although really it is in Earth's atmosphere and so is about one quadrillion times closer. Taken last month on the night of the peak, this meteor is likely from the Perseid meteor shower. The Perseids radiant, in the constellation of Perseus, is off the frame to the upper right, toward the direction that the meteor streak is pointing. The Heart Nebula was imaged in 18 one-minute exposures, of which the unusual meteor streak appeared on just one. The meteor train is multicolored as its glow emanates from different elements in the heated gas. Transparent Science: Browse 1,300+ codes in the Astrophysics Source Code Library

The Whirlpool Galaxy and Beyond

Follow the handle of the Big Dipper away from the dipper's bowl, until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (left), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the human eye, the above long-exposure, deep-field image taken earlier this year shows much of the faint complexity that actually surrounds the smaller galaxy. Thousands of the faint dots in background of the featured image are actually galaxies far across the universe. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter

Eclipse to Sunset

September's eclipse of the Sun is documented in the 68 frames of this timelapse composite. Starting at 1pm local time a frame every 4 minutes follow's the progress of the New Moon across the solar disk. Taken near the centerline of the narrow eclipse path, the series of exposures ends with a golden sunset. Balanced rock cairns in the foreground line a beach on the southern side of Reunion Island in the Indian Ocean, near the village of Etang-Salé. Of course, the close balance in apparent size creates drama in eclipses of the Sun by the Moon as seen from planet Earth. In an annular eclipse, the Moon's silhouette is just small enough to show the solar disk as a narrow ring-of-fire at maximum eclipse phase.

Mars in the Clouds

Wandering through this stunning field of view, Mars really is in front of these colorful cosmic clouds. The mosaic contructed from telescopic images is about 5 degrees (10 full moons) across. It captures the planet's position on August 26, over 7 light-minutes from Earth and very near the line-of-sight to bright star Antares and the Rho Ophiuchi cloud complex. In the exposure yellow-hued Mars, above and left, is almost matched by Antares, also known as Alpha Scorpii, below center. Globular star cluster M4 shines just right of Antares, but M4 lies some 7,000 light-years away compared to Antares' 500 light-year distance. Slightly closer than Antares, Rho Ophiuchi's bluish starlight is reflected by the dusty molecular clouds near the top of the frame.

The Wide and Deep Lagoon

Ridges of glowing interstellar gas and dark dust clouds inhabit the turbulent, cosmic depths of the Lagoon Nebula. Also known as M8, the bright star forming region is about 5,000 light-years distant. But it still makes for a popular stop on telescopic tours of the constellation Sagittarius, toward the center of our Milky Way Galaxy. Dominated by the telltale red emission of ionized hydrogen atoms recombining with stripped electrons, this stunning, deep view of the Lagoon is nearly 100 light-years across. Right of center, the bright, compact, hourglass shape is gas ionized and sculpted by energetic radiation and extreme stellar winds from a massive young star. In fact, the many bright stars of open cluster NGC 6530 drift within the nebula, just formed in the Lagoon several million years ago.

The Launch of OSIRIS-REx

Near sunset on Thursday, clear skies saw the launch of the OSIRIS-REx spacecraft. Sporting a single solid rocket booster, its Atlas V vehicle blasts off from Cape Canaveral's Complex 41 in this low, wide-angle view toward launch pad and setting Sun. OSIRIS-REx is bound for Bennu, scheduled to encounter the mountain-sized asteroid in 2018. First the spacecraft will swing back by home world planet Earth though, for a gravity assist maneuver to boost it on its way. After a detailed survey of Bennu OSIRIS-REx will collect a sample from the asteroid's surface in 2020 and bring it home, returning to Earth in 2023. If all goes well it will be the largest sample returned by a space mission since the Apollo era.

All the Water on Planet Earth

How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius. The featured illustration shows what would happen if all of the water on or near the surface of the Earth were bunched up into a ball. The radius of this ball would be only about 700 kilometers, less than half the radius of the Earth's Moon, but slightly larger than Saturn's moon Rhea which, like many moons in our outer Solar System, is mostly water ice. How even this much water came to be on the Earth and whether any significant amount is trapped far beneath Earth's surface remain topics of research. Poll: Have you seen today's APOD image before?

Philae Lander Found on Comet 67P

A little spacecraft that was presumed lost has now been found. In 2014, the Philae lander slowly descended from its parent Rosetta spacecraft to the nucleus of Comet C67/P Churyumov-Gerasimenko. At the surface, after a harpoon malfunction, the lander bounced softly twice and eventually sent back images from an unknown location. Earlier this month, though, Rosetta swooped low enough to spot its cub. The meter-sized Philae is seen on the far right of the main image, with inset images showing both a zoom out and a zoom in. At the end of this month, Rosetta itself will be directed to land on 67P, but Rosetta's landing will be harder and, although taking unique images and data, will bring the mission to an end. Free Download: APOD 2017 Calendar: NASA Images

NGC 1672: Barred Spiral Galaxy from Hubble

Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a modest central bar. Prominently barred spiral galaxy NGC 1672, featured here, was captured in spectacular detail in an image taken by the orbiting Hubble Space Telescope. Visible are dark filamentary dust lanes, young clusters of bright blue stars, red emission nebulas of glowing hydrogen gas, a long bright bar of stars across the center, and a bright active nucleus that likely houses a supermassive black hole. Light takes about 60 million years to reach us from NGC 1672, which spans about 75,000 light years across. NGC 1672, which appears toward the constellation of the Dolphinfish (Dorado), is being studied to find out how a spiral bar contributes to star formation in a galaxy's central regions. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter

The North and South of Jupiter

A wide, looping orbit brought Juno close to Jupiter on August 27. As the spacecraft swung around the giant planet's poles JunoCam acquired these premier direct polar views, a change from the usual nearly equatorial perspective of outbound spacecraft and the telescopes of planet Earth. The sunlit side of Jupiter's north polar region (left) was imaged about 125,000 kilometers from the cloud tops, two hours before Juno's closest approach. An hour after close approach the south polar region was captured from 94,500 kilometers away. Strikingly different from the alternating light-colored zones and darker belts girdling more familiar equatorial regions, the polar region clouds appear more convoluted and mottled by many clockwise and counterclockwise rotating storm systems. Another 35 close orbital flybys are planned during the Juno mission.

Retrograde Mars and Saturn

Wandering Mars and Saturn have spent much of this year remarkably close in planet Earth's night sky. In a sequence of exposures spanning mid-December 2015 through the beginning of this week, this composited skyview follows their time together, including both near opposition, just north of bright star Antares near the Milky Way's central bulge. In the corresponding video, Saturn's apparent movement is seen to be back and forth along the flattened, compact loop, while Mars traces the wider, reversing S-shaped track from upper right to lower left through the frame. To connect the dots and dates just slide your cursor over the picture (or follow this link). It looks that way, but Mars and Saturn don't actually reverse direction along their orbits. Instead, their apparent backwards or retrograde motion with respect to the background stars is a reflection of the orbital motion of the Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit.

Full Moon over Brno

After sunset this gorgeous full moon rose over Brno city in the Czech Republic on July 20, 2016. The panoramic image was made during a celebration of the 47th anniversary of the Apollo 11 lunar landing. A series of exposures captures the yellow hued lunar disk against the fading colors of twilight, with the 14th century Spilberk castle illuminated in the foreground. Of course, tonight's full moon is called the Harvest Moon. The closest full moon to the northern hemisphere's autumnal equinox, its traditional name has long been celebrated in story and song. Tonight's full lunar phase also coincides with a subtle, penumbral lunar eclipse, the Moon passing only through the Earth's diffuse, outer shadow.

M33: Triangulum Galaxy

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 the view from planet Earth, this sharp composite image nicely shows off M33's blue star clusters and pinkish star forming regions along the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 1 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.

Starry Night Scavenger Hunt

Did you know that van Gogh's painting Starry Night includes Comet Hale-Bopp? Hopefully not, because it doesn't. But the featured image does. Although today's picture may appear at first glance to be a faithful digital reproduction of the original Starry Night, actually it is a modern rendition meant not only to honor one of the most famous paintings of the second millennium, but to act as a scavenger hunt. Can you find, in the featured image, a comet, a spiral galaxy, an open star cluster, and a supernova remnant? Too easy? OK, then find, the rings of Supernova 1987A, the Eskimo Nebula, the Crab Nebula, Thor's Helmet, the Cartwheel Galaxy, and the Ant Nebula. Still too easy? Then please identify any more hidden images not mentioned here -- and there are several -- on APOD's main discussion board: The Asterisk. Finally, the collagist has graciously hidden APOD's 10th anniversary Vermeer photomontage just to honor APOD. (Thanks!) Free Download: APOD 2017 Calendar: NASA Images

50,000 Kilometers over the Sun

What's happening at the edge of the Sun? Although it may look like a monster is rampaging, what is pictured is actually only a monster prominence -- a sheath of thin gas held above the surface by the Sun's magnetic field. The solar event was captured just this past weekend with a small telescope, with the resulting image then inverted and false-colored. As indicated with illustrative lines, the prominence rises over 50,000 kilometers above the Sun's surface, making even our 12,700-diameter Earth seem small by comparison. Below the monster prominence is active region 12585, while light colored filaments can be seen hovering over a flowing solar carpet of fibrils. Filaments are actually prominences seen against the disk of the Sun, while similarly, fibrils are actually spicules seen against the disk. Energetic events like this are becoming less common as the Sun evolves toward a minimum in its 11-year activity cycle. Free Download: APOD 2017 Calendar: NASA Images

The Helix Nebula in Infrared

What makes this cosmic eye look so red? Dust. The featured image from the robotic Spitzer Space Telescope shows infrared light from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation of the Water Carrier Aquarius. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula, representing the final stages in the evolution of a Sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models suggest the glow is produced by a dust debris disk. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could have been generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud. Had the comet-like bodies formed in the distant planetary system, they would have survived even the dramatic late stages of the star's evolution. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter

Zooming in on Star Cluster Terzan 5

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 less than 200 left. Over the eons, many globular clusters were destroyed 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 our Milky Way Galaxy because conditions are not ripe for more to form. The featured video shows what it might look like to go from the Earth to the globular cluster Terzan 5, ending with a picture of the cluster taken with the Hubble Space Telescope. This star cluster was recently found to contain not only stars formed in the early days of our Milky Way Galaxy, but also, quite surprisingly, others that formed in a separate burst of star formation about 7 billion years later.

Sunset at Edmontonhenge

On September 18, the setting Sun illuminated both sides of the steep brick and steel canyon otherwise known as Jasper Avenue in downtown Edmonton, Alberta, Canada, planet Earth. The Stonehenge-like alignment is captured from the middle of the road in this daring snapshot. In Edmonton streets are laid out on a grid almost oriented along the cardinal directions, so aligned Edmonton sunsets (and sunrises) occur along the nearly east-west streets twice a year, close to the Equinox. In fact, at today's Equinox, the Sun crosses the celestial equator at 1421 UT and on this day the Sun will rise due east and set due west, bringing approximately equal hours of day and night to denizens of planet Earth. The September Equinox marks the astronomical beginning of Fall in the north and Spring in the southern hemisphere.

Harvest Moon Eclipse

A Harvest Moon rises over Sesimbra Castle south of Lisbon in this impressive series of telephoto exposures. Captured at its full phase, the golden Moon was also gliding through the Earth's more diffuse outer shadow during September's penumbral lunar eclipse. The eclipse shading is subtle compared to a total lunar eclipse. Still, the penumbral shadow does darken the Moon's upper limb, the pale shadow receding as the Moon climbs into Portugal's evening sky. In this eclipse timelapse the effect of sunlight and earthshadow on the Moon looks remarkably like the coloring of light and shadow along the illuminated castle walls.

Heart and Soul and Double Cluster

This rich starfield spans almost 10 degrees across the sky toward the northern constellations Cassiopeia and Perseus. On the left, heart-shaped cosmic cloud IC 1805 and IC 1848 are popularly known as the Heart and Soul nebulae. Easy to spot on the right are star clusters NGC 869 and NGC 884 also known as h and Chi Perseii, or just the Double Cluster. Heart and Soul, with their own embedded clusters of young stars a million or so years old, are each over 200 light-years across and 6 to 7 thousand light-years away. In fact, they are part of a large, active star forming complex sprawling along the Perseus spiral arm of our Milky Way Galaxy. The Double Cluster is located at about the same distance as the Heart and Soul nebulae. Separated by only a few hundred light-years, h and Chi Perseii are physically close together, and both clusters are estimated to be about 13 million years old. Their proximity and similar stellar ages suggest both clusters are likely a product of the same star-forming region.

Saturn from Above

This image of Saturn could not have been taken from Earth. No Earth based picture could possibly view the night side of Saturn and the corresponding shadow cast across Saturn's rings. Since Earth is much closer to the Sun than Saturn, only the day side of the ringed planet is visible from the Earth. In fact, this image mosaic was taken earlier this year by the robotic Cassini spacecraft now orbiting Saturn, just before filming a 44-hour video of Saturn rotating. The beautiful rings of Saturn are seen in full expanse, while cloud details are visible including the polar hexagon surrounding the north pole. The Cassini mission is now in its final year as the spacecraft is scheduled to be programmed to dive into Saturn's atmosphere next September.

Gaia: Here Comes the Sun

What would it look like to return home from outside our galaxy? Although designed to answer greater questions, recent data from ESA's robotic Gaia mission is helping to provide a uniquely modern perspective on humanity's place in the universe. Gaia orbits the Sun near the Earth and resolves star's positions so precisely that it can determine a slight shift from its changing vantage point over the course of a year, a shift that is proportionately smaller for more distant stars -- and so determines distance. In the first sequence of the video, an illustration of the Milky Way is shown that soon resolves into a three-dimensional visualization of Gaia star data. A few notable stars are labelled with their common names, while others stars are labelled with numbers from Gaia's catalog. Eventually the viewer arrives at our home star Sol (the Sun), then resolving the reflective glow of its third planet: Earth. The featured video is based on just over 600,000 stars, but Gaia is on track to measure the parallax distances to over one billion stars over its planned five year mission.

Jupiter's Europa from Spacecraft Galileo

What mysteries might be solved by peering into this crystal ball? In this case, the ball is actually a moon of Jupiter, the crystals are ice, and the moon is not only dirty but cracked beyond repair. Nevertheless, speculation is rampant that oceans exist under Europa's fractured ice-plains that could support life. This speculation was bolstered again this week by released images from the Hubble Space Telescope indicating that plumes of water vapor sometimes emanate from the ice-crusted moon -- plumes that might bring microscopic sea life to the surface. Europa, roughly the size of Earth's Moon, is pictured here in natural color as photographed in 1996 by the now-defunct Jupiter-orbiting Galileo spacecraft. Future observations by Hubble and planned missions such as the James Webb Space Telescope later this decade and a Europa flyby mission in the 2020s may further humanity's understanding not only of Europa and the early Solar System but also of the possibility that life exists elsewhere in the universe. Free Download: APOD 2017 Calendar: NASA Images

NGC 3576: The Statue of Liberty Nebula

What's happening in the Statue of Liberty nebula? Bright stars and interesting molecules are forming and being liberated. The complex nebula resides in the star forming region called RCW 57. This image showcases dense knots of dark interstellar dust, bright stars that have formed in the past few million years, fields of glowing hydrogen gas ionized by these stars, and great loops of gas expelled by dying stars. A detailed study of NGC 3576, also known as NGC 3582 and NGC 3584, uncovered at least 33 massive stars in the end stages of formation, and the clear presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons (PAHs). PAHs are thought to be created in the cooling gas of star forming regions, and their development in the Sun's formation nebula five billion years ago may have been an important step in the development of life on Earth. The featured image was taken at the Cerro Tololo Inter-American Observatory in Chile. Free Download: APOD 2017 Calendar: NASA Images

Five Hundred Meter Aperture Spherical Telescope

The Five-hundred-meter Aperture Spherical Telescope (FAST) is nestled within a natural basin in China's remote and mountainous southwestern Guizhou province. Nicknamed Tianyan, or the Eye of Heaven, the new radio telescope is seen in this photograph taken near the start of its testing phase of operations on September 25. Designed with an active surface for pointing and focusing, its enormous dish antenna is constructed with 4,450 individual triangular-shaped panels. The 500 meter physical diameter of the dish makes FAST the largest filled, single dish radio telescope on planet Earth. FAST will explore the Universe at radio frequencies, detecting emission from hydrogen gas in the Milky Way and distant galaxies, finding faint galactic and extragalactic pulsars, and searching for potential radio signals from extraterrestrials.

history record