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Explanation: What would it look like to fly past Triton, the largest moon of planet Neptune? Only one spacecraft has ever done this -- and the images of this dramatic encounter have been gathered into a video. In 1989, the Voyager 2 robotic spacecraft shot through the Neptune system with cameras blazing. Triton is slightly smaller than Earth's Moon but has ice volcanoes and a surface rich in frozen nitrogen. The first sequence in the video shows Voyager's approach to Triton, which, with the exception of an overall false green tint, appears in approximately true color. The mysterious cantaloupe terrain...

Explanation: Is this what will become of our Sun? Quite possibly. The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, one of the brightest planetary nebulas on the sky and visible with binoculars toward the constellation of the Fox (Vulpecula). It takes light about 1000 years to reach us from M27, featured here in colors enhanced by red for hydrogen and...

Explanation: What if you could see the entire sky -- all at once -- for an entire year? That, very nearly, is what is pictured here. Every 15 seconds during 2025, an all-sky camera took an image of the sky over the Netherlands. Central columns from these images were then aligned and combined to create the featured keogram, with January at the top, December at the bottom, and the middle of the night running vertically just left of center. What do we see? Most obviously, the daytime sky is mostly blue, while the nighttime sky is mostly black. The twelve...

Explanation: Does this scene look familiar? It is a modern recreation of the famous painting Starry Night by Vincent van Gogh. Both the image and the painting depict a tall tree on the left, a crescent moon on the upper right, the planet Venus just to the right of the tree, a foreground horizon rising from left to right, and clouds above the horizon. Differences include that the photograph was taken in mid-April earlier this year in Cascavel, Brazil, while the painting was composed in Saint-Rémy-de-Provence, France, in 1889. The original Starry Night is considered by many to be one...

Explanation: Do you see that blue blob to the lower right of the image center? Astronomers think that it shows where a massive star exploded as a supernova whose light reached Earth 1,700 years ago. The image combines optical data from the PanSTARRS telescopes in Hawaii (background stars in red, green, and blue), radio from the MeerKAT telescope in South Africa (large red cloud) and X-rays from NASA's Chandra X-ray Observatory and ESA’s XMM-Newton (shown in blue). The large cloud is a star forming region called Sagittarius C, which is approximately 50 light-years in extent and about 26,000 light-years from...

Explanation: How did a hamster wheel get into space? The Hamster Wheel Nebula (Longmore 8) was discovered by Andrew Longmore in 1976 as a part of a larger survey of the southern sky. This survey employed several improvements in photographic technology, including the use of highly sensitive film, to capture deeper and fainter objects on plates that were examined by eye and catalogued. The featured image, taken at Observatorio El Sauce in Chile, depicts an intricate wheel structure of glowing hydrogen that was thrown out into space by a dying star and ionized by the leftover white dwarf. This structure...

Explanation: While cruising around Saturn, be on the lookout for picturesque arrangements of moons, rings, and shadows. One such striking sight occurred in 2005 and was captured by the then Saturn-orbiting Cassini spacecraft. In the featured image, moons Mimas (left) and Tethys (right) are visible on either side of Saturn's thin rings, which are seen nearly edge-on. Across the top of Saturn are dark shadows of the wide rings, exhibiting their impressive complexity. The violet-light image brings up the texture of the backdrop: Saturn's clouds. Cassini orbited Saturn from 2004 until mid-2017, when the robotic spacecraft was directed to dive...

Explanation: What's happening to this Sun-crossing rocket? The SpaceX Falcon 9 rocket, visible on the upper left, launched only about one minute before this amazing image was captured. As it rose to low Earth orbit from Cape Canaveral, Florida, USA, in late May, the rocket became supersonic before it crossed the disk of the distant Sun -- from the perspective of the well-placed photographer. The spacecraft's high speed caused bow-shaped compressed-air shockwaves to form across leading surfaces, with at least three visible even outside the Sun's disk because they refract sunlight. The trailing exhaust caused turbulence visible on the lower...

Explanation: Venus and Jupiter may have caught your attention lately. The recent close conjunction of the two brightest planets in recent evening skies has been hard to miss. With Jupiter at the top, starting on May 30 and ending on June 8, their close approach was chronicled daily, left to right, in the featured panels from Maharashtra, India. Near the western horizon, the evening sky colors and exposures used for each panel depend on the local conditions near sunset. At their closest on June 9, the celestial pair appeared to be only about three times the width of a full...

Explanation: In an interplanetary first, on July 19, 2013 Earth was photographed on the same day from two other worlds of the Solar System, innermost planet Mercury and ringed gas giant Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft then orbiting the outermost gas giant. On that same day people across planet Earth snapped many of their own pictures of Saturn. On the right, the Earth-Moon system is seen against the dark background of space as captured by the sunward MESSENGER spacecraft, then in...

Explanation: To see Venus and Jupiter together this month, you won't need binoculars or even a telescope. Just look up after sunset and you'll find them emerging as the sky grows dark near the western horizon. In fact, on June 9 the two brightest planets were in close conjunction, separated on the sky by less than 2 degrees from our perspective. Since (brighter) inner planet Venus orbits the Sun faster than outer planet Jupiter, it catches up with and passes the outer planet along the ecliptic roughly every 13 months. But every three years or so their resulting conjunction can...

Explanation: Could the Little Mermaid turn into stardust instead of seafoam? It would seem so in this beautiful nebula. The featured image shows the Mermaid Nebula, also known as the Betta Fish Nebula, which is part of the G296.5+10.0 Supernova Remnant. The blue color visible here originates from doubly ionized oxygen (OIII), while the deep red is emitted by hydrogen gas. Estimated to be located a few thousand light-years away and about 10,000 years old, this nebula was formed when a massive star exploded as a supernova. It left behind a peculiar pulsar, a young radio-quiet neutron star that spins...

Explanation: What looks as if it is going to swallow the great Pillars of Creation? The Eagle Nebula (M16) is not a bird, a plane, or Superman. M16 is actually a combination of several celestial objects. NGC 6611 is the young star cluster that appears to peak out beneath the Eagle’s “wings”. The ultraviolet light from these stars ionizes the surrounding gas, creating the emission nebula IC 4703. The Stellar Spire is seen reaching towards the Pillars of Creation from the left. Both are structures of cold gas and dust that are optimal for star formation. Some astronomers previously thought...

Explanation: Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the cosmic head-covering is more like an interstellar bubble, blown by a fast wind from the bright, massive star near the bubble's center. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away toward...

Explanation: What happens to a comet as it leaves our inner Solar System? Now, the arrival of a comet into the inner Solar System is typically heralded with great fanfare and high hopes that the comet will become bright and photogenic. But on the way out, the comet's nucleus is less warmed by the Sun, less gas and dust are expelled, the bright coma around the nucleus shrinks and fades, and the tail length drops off. Many comets will then return to the outer Solar System and only return in hundreds or thousands of years. In contrast, some comets --...

Explanation: It was visible around the world. The sunset conjunction of Jupiter (left) and Venus (right) in 2012 was visible almost no matter where you lived on Earth. Anyone on our planet with a clear western horizon at sunset could see them. That year, a creative photographer traveled away from the town lights of Szubin, Poland to photograph a near closest approach of the two planets. The bright planets were then separated by only three degrees and his daughter struck a humorous pose. A faint red sunset still glowed in the background. Jupiter and Venus are together again this week...

Explanation: A darkened and mysterious north polar region known to some as Mordor Macula caps this premier view of Charon, Pluto's largest moon. The high-resolution image was captured by the interplanetary space probe New Horizons near its closest approach to distant Pluto on July 14, 2015. The combined blue, red, and infrared image data was processed to enhance colors and follow variations in Charon's surface properties with a resolution of about 2.9 kilometers (1.8 miles). A stunning image of Charon's Pluto-facing hemisphere, it also features a clear view of an apparently moon-girdling belt of fractures and canyons that seems to...

Explanation: Within our own Milky Way galaxy, two bright, spiky stars stand like sentinels in the foreground of this cosmic snapshot. Far beyond them are the galaxies of the Hydra Cluster. In fact, while the spiky foreground stars are hundreds of light-years distant, the Hydra Cluster galaxies are well over 100 million light-years away. Three large galaxies near the cluster center, two yellow ellipticals (NGC 3311, NGC 3309) and one prominent blue spiral (NGC 3312), are the dominant galaxies, each about 150,000 light-years in diameter. An intriguing overlapping galaxy pair cataloged as NGC 3314 lies above and left of NGC...

Explanation: What is happening inside this unusual nebula? Planetary nebula Tc 1, captured here in exquisite detail by the James Webb Space Telescope, is the celestial site where buckyballs were first identified in 2010. Buckminsterfullerene — as buckyballs are officially called — is a molecule with 60 carbon atoms (C60) arranged in the shape of a soccer ball. The molecule is named for architect Buckminster Fuller because of its resemblance to the geodesic dome he helped popularize. Webb’s new data reveal where the C60 molecules live in this nebula, and the geometry is striking: they populate a thin spherical shell...

Explanation: Over 1000 years ago, Persian astronomer Abd al-Rahman al-Sufi published humanity’s oldest known record of the Andromeda Galaxy in "The Book of Fixed Stars" (Bodleian Library MS. Marsh 144 p. 167). 800 years later, Andromeda became the 31st entry in Charles Messier’s "Catalogue of Nebulae and Star Clusters". From “a small cloud” to “nebula” and now known to be our nearest major galaxy, Andromeda has remained a fundamental astronomical object. Today’s image, taken over 202 hours, shows how far we have come in our ability to observe our neighbor. The diffuse red and blue clouds are mostly foreground ionized...