Astronomy Picture of the Day

🌌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 ...

© Petr Horálek

🌌Twelve Years of Kappa Cygnids Meteors from the Kappa Cygnid meteor shower are captured in this time-lapse composite skyscape. The minor meteor shower, with a radiant not far from its eponymous star Kappa Cygni, peaks in mid-August, almost at the same time as the much better-known and better-observed Perseid meteor shower. But, seen to have a peak rate of only about 3 meteors per hour, Kappa Cyg ...

© Every 15 years or so

🌌Titan Shadow Transit very 15 years or so, Saturn's rings are tilted edge-on to our line of sight. As the bright, beautiful ring system grows narrower and fainter it becomes increasingly difficult to see for denizens of planet Earth. But it does provide the opportunity to watch transits of Saturn's moons and their dark shadows across the ringed gas giant's still bright disk. Of course Saturn's l ...

© Jason Rice

🌌Fireball over Cape San Blas Have you ever seen a fireball? In astronomy, a fireball is a very bright meteor -- one at least as bright as Venus and possibly brighter than even a full Moon. Fireballs are rare -- if you see one you are likely to remember it for your whole life. Physically, a fireball is a small rock that originated from an asteroid or comet that typically leaves a fading smoke tra ...

🌌A Double Detonation Supernova Can some supernovas explode twice? Yes, when the first explosion acts like a detonator for the second. This is a leading hypothesis for the cause of supernova remnant (SNR) 0509-67.5. In this two-star system, gravity causes the larger and fluffier star to give up mass to a smaller and denser white dwarf companion. Eventually the white dwarf's near-surface temperatu ...

🌌Cat's Paw Nebula from Webb Space Telescope Nebulas are perhaps as famous for being identified with familiar shapes as perhaps cats are for getting into trouble. Still, no known cat could have created the vast Cat's Paw Nebula visible toward the constellation of the Scorpion (Scorpius). At 5,700 light years distant, Cat's Paw is an emission nebula within a larger molecular cloud. Alternatively k ...

🌌Lunar Nearside About 1,300 images from the Lunar Reconnaissance Orbiter spacecraft's wide angle camera were used to compose this spectacular view of a familiar face - the lunar nearside. But why is there a lunar nearside? The Moon rotates on its axis and orbits the Earth at the same rate, about once every 28 days. Tidally locked in this configuration, the synchronous rotation always keeps one s ...

© Xinran Li

🌌Messier 6 The sixth object in Charles Messier's famous catalog of things which are not comets, Messier 6 is a galactic or open star cluster. A gathering of 100 stars or so, all around 100 million years young, M6 lies some 1,600 light-years away toward the central Milky Way in the constellation Scorpius. Also cataloged as NGC 6405, the pretty star cluster's outline suggests its popular moniker, ...

© A.J. Smadi

🌌ISS Meets Saturn This month, bright planet Saturn rises in evening skies, its rings oriented nearly edge-on when viewed from planet Earth. And in the early morning hours on July 6, it posed very briefly with the International Space Station when viewed from a location in Federal Way, Washington, USA. This well-planned image, a stack of video frames, captures their momentary conjunction in the sa ...

🌌3I/ATLAS Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert, System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System It follows 1I/ʻOumuamua in 2017 and the comet 2I/Borisov in 2019. Also known as C/2025 N1, 3I/ATLAS is clearly a comet, its diffuse cometary coma, a clou ...

🌌The Rosette Nebula from DECam Would the Rosette Nebula by any other name look as sweet? The bland New General Catalog designation of NGC 2237 doesn't appear to diminish the appearance of this flowery emission nebula, as captured by the Dark Energy Camera (DECam) on the Blanco 4-meter telescope at the NSF's Cerro Tololo Inter-American Observatory in Chile. Inside the nebula lies an open cluster ...

🌌Collapse in Hebes Chasma on Mars What's happened in Hebes Chasma on Mars? Hebes Chasma is a depression just north of the enormous Valles Marineris canyon. Since the depression is unconnected to other surface features, it is unclear where the internal material went. Inside Hebes Chasma is Hebes Mensa, a 5 kilometer high mesa that appears to have undergone an unusual partial collapse -- a collaps ...

© Stefan Thrun

🌌NGC 2685: The Helix Galaxy What is going on with this galaxy? NGC 2685 is a confirmed polar ring galaxy - a rare type of galaxy with stars, gas and dust orbiting in rings perpendicular to the plane of a flat galactic disk. The bizarre configuration could be caused by the chance capture of material from another galaxy by a disk galaxy, with the captured debris strung out in a rotating ring. Stil ...

🌌Planetary Nebula Mz3: The Ant Nebula Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round? Clues might include the high 1000-kilometer per second speed of the expelled gas, the light-year long length of the structure, and ...

© Alexsandro Mota

🌌Clouds and the Golden Moon As the Sun set, a bright Full Moon rose on July 10. Its golden light illuminates clouds drifting through southern hemisphere skies in this well-composed telephoto image from Conceição do Coité, Bahia, Brazil. The brightest lunar phase is captured here with both a short and long exposure. The two exposures were combined to reveal details of the lunar surface in bright ...

© Clear Skies

🌌The Veins of Heaven Transfusing sunlight as the sky grew darker, this exceptional display of noctilucent clouds was captured on July 10, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers above Earth's surface, the icy clouds themselves still reflect sunlight, even though the Sun is below the horizon as seen from the ground. Usual ...

© Cristiano Gualco

🌌Lynds Dark Nebula 1251 Stars are forming in Lynds Dark Nebula (LDN) 1251. About 1,000 light-years away and drifting above the plane of our Milky Way galaxy, LDN 1251 is also less appetizingly known as "The Rotten Fish Nebula." The dusty molecular cloud is part of a complex of dark nebulae mapped toward the Cepheus flare region. Across the spectrum, astronomical explorations of the obscuring int ...

© Alessandro Cipolat Bares

🌌A Beautiful Trifid The beautiful Trifid Nebula is a cosmic study in contrasts. Also known as M20, it lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid does illustrate three different types of astronomical nebulae; red emission nebulae dominated by light from hydrogen atoms, blue reflection nebulae pro ...

© Ogetay Kayali (Michigan Tech U.) Text: Ogetay Kayali (Michigan Tech U.)

🌌The Pleiades in Red and Blue If you have looked at the sky and seen a group of stars about the size of the full Moon, that's the Pleiades (M45). Perhaps the most famous star cluster in the sky, its brightest stars can be seen even from the light-polluted cities. But your unaided eye can also see its nebulosity -- the gas and dust surrounding it -- under dark skies. However, telescopes can catch ...

🌌Interstellar Comet 3I/ATLAS It came from outer space. An object from outside our Solar System is now passing through at high speed. Classified as a comet because of its gaseous coma, 3I/ATLAS is only the third identified macroscopic object as being so alien. The comet's trajectory is shown in white on the featured map, where the orbits of Jupiter, Mars, and Earth are shown in gold, red, and blu ...

🌌The Spiral North Pole of Mars Why is there a spiral around the North Pole of Mars? Each winter this pole develops a new outer layer about one meter thick composed of carbon dioxide frozen out of the thin Martian atmosphere. This fresh layer is deposited on a water-ice layer that exists year round. Strong winds blow down from above the cap's center and swirl due to the spin of the red planet -- ...

© Massimo Di Fusco

🌌Ou4: The Giant Squid Nebula Difficult to capture, this mysterious, squid-shaped interstellar cloud spans nearly three full moons in planet Earth's sky. Discovered in 2011 by French astro-imager Nicolas Outters, the Squid Nebula's bipolar shape is distinguished here by the telltale blue emission from doubly ionized oxygen atoms. Though apparently surrounded by the reddish hydrogen emission regio ...

© Alberto Pisabarro

🌌NGC 6946 and NGC 6939 Face-on spiral galaxy NGC 6946 and open star cluster NGC 6939 share this cosmic snapshot, composed with over 68 hours of image data captured with a small telescope on planet Earth. The field of view spans spans about 1 degree or 2 full moons on the sky toward the northern constellation Cepheus. Seen through faint interstellar dust couds near the plane of our Milky Way gala ...

© Matipon Tangmatitham (NARIT)

🌌Nova V462 Lupi Now Visible If you know where to look, you can see a thermonuclear explosion from a white dwarf star. Possibly two. Such explosions are known as novas and the detonations are currently faintly visible with the unaided eye in Earth's southern hemisphere -- but are more easily seen with binoculars. Pictured, Nova Lupi 2025 (V462 Lupi) was captured toward the southern constellation ...

© Kavan Chay; Text: Ogetay Kayali (Michigan Tech U.)

🌌Milky Way Through Otago Spires Does the Milky Way always rise between these two rocks? No. Capturing this stunning alignment took careful planning: being in the right place at the right time. In the featured image taken in June 2024 from Otago, New Zealand, the bright central core of our Milky Way Galaxy, home to the many of our Galaxy's 400 billion stars, can be seen between two picturesque ro ...

© Anton Komlev