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Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris...

Explanation: What would it be like to fly over the largest moon in the Solar System? In 2021, the robotic Juno spacecraft flew past Jupiter's huge moon Ganymede and took images that have been digitally constructed into a detailed flyby. As the featured video begins, Juno swoops over the two-toned surface of the 2,000-km wide moon, revealing an icy alien landscape filled with grooves and craters. The grooves are likely caused by shifting surface plates, while the craters are caused by violent impacts. Continuing on in its orbit, Juno then performed its 34th close pass over Jupiter's clouds. The digitally-constructed...

Explanation: On December 5, 2022, a camera on board the uncrewed Orion spacecraft captured this view as Orion approached its return powered flyby of the Moon. Beyond one of Orion's extended solar arrays lies dark, smooth, terrain along the western edge of the Oceanus Procellarum. Prominent on the lunar nearside Oceanus Procellarum, the Ocean of Storms, is the largest of the Moon's lava-flooded maria. The lunar terminator, the shadow line between lunar night and day, runs along the left of this frame. The 41 kilometer diameter crater Marius is top center, with ray crater Kepler peeking in at the edge,...

Explanation: In a Finnish myth, when an arctic fox runs so fast that its bushy tail brushes the mountains, flaming sparks are cast into the heavens creating the northern lights. In fact the Finnish word "revontulet", a name for the aurora borealis or northern lights, can be translated as fire fox. So that evocative myth took on a special significance for the photographer of this northern night skyscape from Finnish Lapland near Kilpisjarvi Lake. The snowy scene is illuminated by moonlight. Saana, an iconic fell or mountain of Lapland, rises at the right in the background. But as the beautiful...

Explanation: Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity. In fact, the practice is common in the universe and illustrated by this striking pair of interacting galaxies from the banks of the southern constellation Eridanus, The River. Located over 50 million light years away, the large, distorted spiral NGC 1532 is seen locked in a gravitational struggle with dwarf galaxy NGC 1531, a struggle the smaller galaxy will eventually lose. Seen nearly edge-on in this...

Explanation: Sculpted by stellar winds and radiation, this dusty interstellar molecular cloud has by chance assumed an immediately recognizable shape. Fittingly known as The Horsehead Nebula, it lies some 1,500 light-years distant, embedded in the vast Orion cloud complex. About five light-years "tall," the dark cloud is cataloged as Barnard 33, first identified on a photographic plate taken in the early 20th century. B33 is visible primarily because its obscuring dust is silhouetted against the glow of emission nebula IC 434. Hubble Space Telescope images from the early 21st century find young stars forming within B33. Of course, the magnificent...

Explanation: This cosmic close-up looks deep inside the Soul Nebula. The dark and brooding dust clouds outlined by bright ridges of glowing gas are cataloged as IC 1871. About 25 light-years across, the telescopic field of view spans only a small part of the much larger Heart and Soul nebulae. At an estimated distance of 6,500 light-years, the star-forming complex lies within the Perseus spiral arm of the Milky Way, seen in planet Earth's skies toward the constellation of the Queen of Aethiopia (Cassiopeia). An example of triggered star formation, the dense star-forming clouds of IC 1871 are themselves sculpted...

Explanation: Many wonders are visible when flying over the Earth at night. Such visual spectacles occur every day for astronauts in low Earth orbit, but the featured video captured several from the International Space Station (ISS) in 2011 and set them to rousing music. Passing below are white clouds, orange city lights, lightning flashes in thunderstorms, and dark blue seas. On the horizon is the golden haze of Earth's thin atmosphere, frequently decorated by dancing auroras as the video progresses. The green parts of auroras typically remain below the space station, but the station flies right through the red and...

Explanation: Comet C/2025 R2 (SWAN) sports a greenish coma and fainter tail, seen against congeries of stars and dusty interstellar clouds in this 7 degree wide telescopic field of view from October 17. On that date, the new visitor to the inner Solar System obligingly posed with two other celestial birds seen toward the center of our Milky Way. Messier 16, near the bottom of the frame, and Messier 17 are also known to deep skywatchers as the Eagle and the Swan nebulae. While the comet coma's greenish glow recorded in the image is due to diatomic carbon gas fluorescing...

Explanation: It is still not known why the Sun's light is missing some colors. Here are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device. The spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our white-appearing Sun emits light of nearly every color, it appears brightest in yellow-green light. The dark patches in the featured spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine what gasses...

Explanation: Fifty three years ago, in December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon exploring the Taurus-Littrow valley, while colleague Ronald Evans orbited overhead. This snapshot from another world was taken by Cernan as he and Schmitt roamed the lunar valley's floor. The image shows Schmitt next to the lunar rover parked along the south rim of Shorty Crater. That location is near the spot where geologist Schmitt discovered orange lunar soil. The Apollo 17 crew returned with 110 kilograms of rock and soil samples, more than was returned from...

Explanation: Blasting outward from variable star KX Andromedae, these stunning bipolar jets are 19 light-years long. Recently discovered, they are revealed in unprecedented detail in this deep telescopic image centered on KX And and composed from over 692 hours of combined image data. In fact, KX And is spectroscopically found to be an interacting binary star system consisting of a bright, hot B-type star with a swollen cool giant star as its co-orbiting, close companion. The stellar material from the cool giant star is likely being transferred to the hot B-type star through an accretion disk, with spectacular symmetric jets...

Explanation: Tonight, if you can see the stars of the Big Dipper, then you can find comet Lemmon in your evening sky. After sunset, look for the faint but extended comet above your northwestern horizon -- but below the handle of the famous celestial kitchen utensil of the north. It might be easier to see this visitor to the inner Solar System through your camera phone, which is better at picking up faint objects. Either way, look for a fuzzy green 'star' with a tail, though probably not so long a tail as in this impressive snapshot taken over Seč...

Explanation: An example of violence on a cosmic scale, enormous elliptical galaxy NGC 1316 lies about 75 million light-years away toward Fornax, the southern constellation of the Furnace. Investigating the startling sight, astronomers suspect the giant galaxy of colliding with smaller neighbor NGC 1317 seen just right of the large galaxy's center, producing far flung star streams in loops and shells. Light from their close encounter would have reached Earth some 100 million years ago. In the sharp telescopic image, the central regions of NGC 1316 and NGC 1317 appear separated by over 100,000 light-years. Complex dust lanes visible within...

Explanation: What would it look like to plunge into a monster black hole? This image from a supercomputer visualization shows the entire sky as seen from a simulated camera plunging toward a 4-million-solar-mass black hole, similar to the one at the center of our galaxy. The camera lies about 16 million kilometers from the black hole’s event horizon and is moving inward at 62% the speed of light. Thanks to gravity’s funhouse effects, the starry band of the Milky Way appears both as a compact loop at the top of this view and as a secondary image stretching across the...

Explanation: What's happening in the center of nearby spiral galaxy M77? The face-on galaxy lies a mere 47 million light-years away toward the constellation of the Sea Monster (Cetus). At that estimated distance, this gorgeous island universe is about 100 thousand light-years across. Also known as NGC 1068, its compact and very bright core is well studied by astronomers exploring the mysteries of supermassive black holes in active Seyfert galaxies. M77's active core glows bright at x-ray, ultraviolet, visible, infrared, and radio wavelengths. The featured sharp image of M77 was taken by the Hubble Space Telescope. The image shows details...

Explanation: This asteroid has a moon. The robot spacecraft Galileo enroute to explore the Jovian system in 1993, encountered and photographed two asteroids during its long interplanetary voyage. The second minor planet it photographed, 243 Ida, was discovered to have a moon. The tiny moon, named Dactyl, is only about 1.6 kilometers across and seen as a small dot to the right in the image. In contrast, Ida is much larger, measuring about 60 kilometers long and 25 km wide. In fact, Dactyl is the first moon of an asteroid ever discovered. But now many asteroids are known to have...

Explanation: How typical is our Solar System? Studying 3I/ATLAS, a comet just passing through, is providing clues. Confirmed previous interstellar visitors include an asteroid, a comet, a meteor, and a gas wind dominated by hydrogen and helium. Comet 3I/ATLAS appears relatively normal when compared to Solar System comets, therefore providing more evidence that our Solar System is a somewhat typical star system. For example, Comet 3I/ATLAS has a broadly similar chemical composition and ejected dust. The featured image was captured last week from Texas and shows a green coma, a wandering blue-tinted ion tail likely deflected by our Sun's wind,...

Explanation: If you could stand on Titan -- what would you see? The featured color view from Titan gazes across an unfamiliar and distant landscape on Saturn's largest moon. The scene was recorded by ESA's Huygens probe in 2005 after a 2.5-hour descent through a thick atmosphere of nitrogen laced with methane. Bathed in an eerie orange light at ground level, rocks strewn about the scene could well be composed of water and hydrocarbons frozen solid at an inhospitable temperature of negative 179 degrees C. The large light-toned rock below and left of center is only about 15 centimeters across...

Explanation: This is not a screen from a video game. Nestled below the treeline, the small mountain church does look like it might be hiding from Moon though. In the well-composed telephoto snapshot, taken on November 23, the church walls are partly reflecting light from terrestrial flood lights. Of course, the Moon is reflecting light from the Sun. At any given time the Sun illuminates fully half of the Moon's surface, also known as the lunar dayside, but on that night only a sliver of its sunlit surface was visible. About three days after New Moon, the Moon was in...