Astronomy Picture of the Day

🌌Comet Olbers over Kunetice Castle A visitor to the inner solar system every 70 years or so Comet 13P/Olbers reached its most recent perihelion, or closest approach to the Sun, on June 30 2024. Now on a return voyage to the distant Oort cloud the Halley-type comet is recorded here sweeping through northern summer night skies over historic Kunetice Castle, Czech Republic. Along with a broad dust ...

🌌Leopard Spots on Martian Rocks What is creating these unusual spots? Light-colored spots on Martian rocks, each surrounded by a dark border, were discovered earlier this month by NASA's Perseverance Rover currently exploring Mars. Dubbed leopard spots because of their seemingly similarity to markings on famous Earth-bound predators, these curious patterns are being studied with the possibility ...

🌌Arp 142: Interacting Galaxies from Webb To some, it looks like a penguin. But to people who study the universe, it is an interesting example of two big galaxies interacting. Just a few hundred million years ago, the upper NGC 2936 was likely a normal spiral galaxy: spinning, creating stars, and minding its own business. Then it got too close to the massive elliptical galaxy NGC 2937, below, and ...

© Max Inwood

🌌Milky Way over Uluru What's happening above Uluru? A United Nations World Heritage Site, Uluru is an extraordinary 350-meter high mountain in central Australia that rises sharply from nearly flat surroundings. Composed of sandstone, Uluru has slowly formed over the past 300 million years as softer rock eroded away. The Uluru region has been a home to humans for over 22,000 years. Recorded last ...

🌌Sun Dance Sometimes, the surface of our Sun seems to dance. In the middle of 2012, for example, NASA's Sun-orbiting Solar Dynamic Observatory spacecraft imaged an impressive prominence that seemed to perform a running dive roll like an acrobatic dancer. The dramatic explosion was captured in ultraviolet light in the featured time-lapse video covering about three hours. A looping magnetic field ...

© Chengcheng Xu

🌌Saturn at the Moon's Edge Saturn now rises before midnight in planet Earth's sky. On July 24, the naked-eye planet was in close conjunction, close on the sky, to a waning gibbous Moon. But from some locations on planet Earth the ringed gas giant was occulted, disappearing behind the Moon for about an hour from skies over parts of Asia and Africa. Because the Moon and bright planets wander throu ...

© Roberto Marinoni

🌌Facing NGC 6946 From our vantage point in the Milky Way Galaxy, we see NGC 6946 face-on. The big, beautiful spiral galaxy is located just 20 million light-years away, behind a veil of foreground dust and stars in the high and far-off constellation Cepheus. In this sharp telescopic portrait, from the core outward the galaxy's colors change from the yellowish light of old stars in the center to y ...

© Robert Shepherd

🌌NGC 7023: The Iris Nebula These cosmic clouds have blossomed 1,300 light-years away in the fertile starfields of the constellation Cepheus. Called the Iris Nebula, NGC 7023 is not the only nebula to evoke the imagery of flowers. Still, this deep telescopic image shows off the Iris Nebula's range of colors and symmetries embedded in surrounding fields of interstellar dust. Within the Iris itself ...

🌌Exaggerated Moon Our Moon doesn't really have craters this big. Earth's Moon, Luna, also doesn't naturally show this spikey texture, and its colors are more subtle. But this digital creation is based on reality. The featured image is a digital composite of a good Moon image and surface height data taken from NASA's Lunar Orbiter Laser Altimeter (LOLA) mission -- and then exaggerated for educati ...

🌌The Crab Nebula from Visible to X-Ray What powers the Crab Nebula? A city-sized magnetized neutron star spinning around 30 times a second. Known as the Crab Pulsar, it is the bright spot in the center of the gaseous swirl at the nebula's core. About 10 light-years across, the spectacular picture of the Crab Nebula (M1) frames a swirling central disk and complex filaments of surrounding and expa ...

© Chang Lee

🌌Chamaeleon Dark Nebulas Sometimes the dark dust of interstellar space has an angular elegance. Such is the case toward the far-south constellation of Chamaeleon. Normally too faint to see, dark dust is best known for blocking visible light from stars and galaxies behind it. In this 36.6-hour exposure, however, the dust is seen mostly in light of its own, with its strong red and near-infrared co ...

© Wayne Pinkston (LightCrafter Photography)

🌌King of Wings Hoodoo under the Milky Way This rock structure is not only surreal -- it's real. Perhaps the reason it's not more famous is that it is smaller than one might guess: the capstone rock overhangs only a few meters. Even so, the King of Wings outcrop, located in New Mexico, USA, is a fascinating example of an unusual type of rock structure called a hoodoo. Hoodoos may form when a laye ...

🌌Apollo 11 Landing Panorama Have you seen a panorama from another world lately? Assembled from high-resolution scans of the original film frames, this one sweeps across the magnificent desolation of the Apollo 11 landing site on the Moon's Sea of Tranquility. The images were taken 55 years ago by Neil Armstrong looking out his window on the Eagle Lunar Module shortly after the July 20, 1969 land ...

© Pavel Gabzdyl

🌌Anticrepuscular Rays at the Planet Festival For some, these subtle bands of light and shadow stretched across the sky as the Sun set on July 11. Known as anticrepuscular rays, the bands are formed as a large cloud bank near the western horizon cast long shadows through the atmosphere at sunset. Due to the camera's perspective, the bands of light and shadow seem to converge toward the eastern (o ...

© Christopher Freeburn

🌌Messier 24: Sagittarius Star Cloud Unlike most entries in Charles Messier's famous catalog of deep sky objects, M24 is not a bright galaxy, star cluster, or nebula. It's a gap in nearby, obscuring interstellar dust clouds that allows a view of the distant stars in the Sagittarius spiral arm of our Milky Way galaxy. Direct your gaze through this gap with binoculars or small telescope and you are ...

🌌Villarrica Volcano Against the Sky When Vulcan, the Roman god of fire, swings his blacksmith's hammer, the sky is lit on fire. A recent eruption of Chile's Villarrica volcano shows the delicate interplay between this fire -- actually glowing steam and ash from melted rock -- and the light from distant stars in our Milky Way galaxy and the Magellanic Clouds galaxies. In the featured timelapse vi ...

© Mark Hanson & Martin Pugh, Observatorio El Sauce

🌌Cometary Globules What are these unusual interstellar structures? Bright-rimmed, flowing shapes gather near the center of this rich starfield toward the borders of the nautical southern constellations Pupis and Vela. Composed of interstellar gas and dust, the grouping of light-year sized cometary globules is about 1300 light-years distant. Energetic ultraviolet light from nearby hot stars has m ...

🌌The Tadpole Galaxy from Hubble Why does this galaxy have such a long tail? In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation of the Dragon (Draco). Its eye-catching tail is abou ...

© Aman Chokshi

🌌Meteor Misses Galaxy The galaxy was never in danger. For one thing, the Triangulum galaxy (M33), pictured, is much bigger than the tiny grain of rock at the head of the meteor. For another, the galaxy is much farther away -- in this instance 3 million light years as opposed to only about 0.0003 light seconds. Even so, the meteor's path took it angularly below the galaxy. Also the wind high in E ...

🌌Solar System Family Portrait In 1990, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. In it, Voyager's wide-angle camera frames sweep through the inner Solar System at the left, linking up with ice giant Ne ...

© Team OURANOS

🌌Jones-Emberson 1 Planetary nebula Jones-Emberson 1 is the death shroud of a dying Sun-like star. It lies some 1,600 light-years from Earth toward the sharp-eyed constellation Lynx. About 4 light-years across, the expanding remnant of the dying star's atmosphere was shrugged off into interstellar space, as the star's central supply of hydrogen and then helium for fusion was depleted after billio ...

© Juergen Stein

🌌Globular Cluster Omega Centauri Globular star cluster Omega Centauri packs about 10 million stars much older than the Sun into a volume some 150 light-years in diameter. Also known as NGC 5139, at a distance of 15,000 light-years it's the largest and brightest of 200 or so known globular clusters that roam the halo of our Milky Way galaxy. Though most star clusters consist of stars with the sam ...

© Andy Ermolli

🌌A Sagittarius Triplet These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula above center, and colorful M20 below and left in the frame. The third emission region includes NGC 6559, right of M8 and separ ...

© Pascal Fouquet

🌌Noctilucent Clouds over Florida These clouds are doubly unusual. First, they are rare noctilucent clouds, meaning that they are visible at night -- but only just before sunrise or just after sunset. Second, the source of these noctilucent clouds is actually known. In this rare case, the source of the sunlight-reflecting ice-crystals in the upper atmosphere can be traced back to the launch of a ...

© Martin Vargic, Halcyon Maps

🌌Exoplanet Zoo: Other Stars Do other stars have planets like our Sun? Surely they do, and evidence includes slight star wobbles created by the gravity of orbiting exoplanets and slight star dimmings caused by orbiting planets moving in front. In all, there have now been over 5,500 exoplanets discovered, including thousands by NASA's space-based Kepler and TESS missions, and over 100 by ESO's gro ...

🌌Iridescent Clouds over Sweden Why are these clouds multi-colored? A relatively rare phenomenon in clouds known as iridescence can bring up unusual colors vividly -- or even a whole spectrum of colors simultaneously. These polar stratospheric clouds also, known as nacreous and mother-of-pearl clouds, are formed of small water droplets of nearly uniform size. When the Sun is in the right position ...

© Massimo Di Fusco