NASA IOD

Some 190 million light-years away, far beyond the bright stars and nebulae of the Milky Way, these three galaxies are drawn together by gravity in a mesmerizing cosmic dance. Clearly distorted by galactic-scale gravitational interactions, large spiral galaxies NGC 6769 and NGC 6770 are seen face-on, with luminous galactic disks scarred by obscuring interstellar dust lanes. Their young blue star clusters along drawn out spiral arms are spawned in star forming regions that resulted from collisions of massive molecular clouds. Below, spiral NGC 6771 presents a more edge-on perspective, its boxy central bulge due to tidal star streams. Of course, in the distant future a merger of the three galaxies is inevitable. At the estimated distance of this galaxy trio, known to some as the Devil's Mask, the sharp telescopic frame spans over 300 thousand light-years within the boundaries of the far southern constellation Pavo.

What happens when one of the stars in a binary goes supernova? This image combines visible (yellow), ultraviolet (purple) and infrared light (cyan, red and orange) to show two supernova remnants and their surrounding environment, about 6,000 light-years away. The younger one is the well-known Jellyfish Nebula in the center (mostly in yellow). If we could see it by eye, it would appear larger than the full moon in the sky. The filament shown in purple is part of an older, overlapping supernova remnant, G189.6+3.3. A new study used data from NASA's Fermi Gamma-ray Space Telescope to piece together their story. Astronomers believe that there were two stars in a binary system, then the first one exploded as a supernova, kicking away its companion, which also exploded as a supernova tens of thousands of years later, creating the superimposed supernova remnants we see today. The bright star on the right is actually a triple star system named Propus.

Although they look like cotton candy, you cannot eat these clouds! Taken in Cádiz, Spain, today's image features the Rho Ophiuchi complex, a rich tapestry of young and old astronomical phenomena. This colorful cloud complex is a nearby star-forming region containing hundreds of young stellar objects, including protostars and T Tauri stars. Light from the triple star system at its center reflects off of small dust grains to create the blue reflection nebula. Ultraviolet light from hot stars ionizes the surrounding hydrogen gas, creating the red emission nebula. Antares, a red supergiant big enough to engulf the Solar System’s asteroid belt, lights up the yellow region. Dark interstellar dust blocks some of the complex’s color. Recent JWST observations exhibit shadows cast by hidden circumstellar disks, the beginning stages of planet formation. Messier 4, a globular cluster almost as old as the universe, sits in the bottom right and witnesses yet another chaotic burst of youth in the Milky Way.

Why are parts of this asteroid's surface so smooth? The answer seems likely to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock. The unusual asteroid Itokawa was visited by the Japanese spacecraft Hayabusa in 2005 which imaged and documented its unusual structure and mysterious lack of craters. Analyses of the border regions between smooth and rugged sections indicate that jostling of the asteroid might be creating segregation between large and small rocks near the surface, like the Brazil nut effect. The robotic Hayabusa actually touched down on one of the smooth patches, dubbed the MUSES Sea, and collected soil samples. These samples were returned to Earth and are not only giving clues to the ancient history of this unusual asteroid, but also about the early years of our entire Solar System. Computer simulations show that 500-meter asteroid Itokawa may impact the Earth within the next few million years. Rocking Space: Today is Asteroid Day

Why is the Cigar Galaxy billowing red smoke? M82, as this starburst galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardly expanding gas and dust, however. Evidence indicates that this gas and dust is being driven out by the combined emerging particle winds of many stars, together creating a galactic superwind. The dust particles are thought to originate in M82's interstellar medium and are actually similar in size to particles in cigar smoke. The featured photographic mosaic combines images taken in visible light from the Hubble Space Telescope and images taken in infrared light from James Webb Space Telescope. It shows the light-colored central galaxy nearly edge on across the image center with tremendous orange and red colored filaments of gas and dust extending both up and down. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light and can be seen in visible light with a small telescope towards the constellation of the Great Bear (Ursa Major).

Right now, one of the largest sunspot groups in recent history is crossing the Sun. Active Region 4478 is not only big -- it's violent, showing tangled magnetic fields capable of throwing off huge clouds of particles into the Solar System. Some of these CMEs might impact the Earth. At the extreme, these solar storms could cause some Earth-orbiting satellites to malfunction, the Earth's atmosphere to slightly distort, and electrical power grids to surge. When impacting Earth's upper atmosphere, these particles can produce beautiful auroras. Pictured here, AR 4478 and its dark sunspots were captured in visible light a few days ago from Barcelona, Spain. Almost as large as AR 3664 was in 2024, the AR 4478 sunspot group is so big that it is visible just with glasses specially designed to view solar eclipses. This week, skygazing enthusiasts all over the globe will not only be tracking AR 4478 during the day -- but keenly watching night skies for its corresponding bright auroras. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)

In this recent HiRISE view from the Mars Reconnaissance Orbiter, the little green dot indicated on the surface of the big Red Planet is the Perseverance Mars rover. Recorded on June 13, the car-sized, six-wheeled robot was imaged a day before completing a Martian marathon, traveling a total distance of 26.218 miles (42.195 kilometers) since it began exploring the surface of Mars. That equivalent marathon distance was achieved by Perseverance on its mission sol (Martian day) 1,890, after about 5 Earth years and 4 Earth months of driving. Perseverance is continuing to hunt for biosignatures. In the HiRISE image, the Mars rover's tracks can be seen leading to its location in an area west of its landing site in Jezero crater near an ancient river delta.

In a cosmic vista you can never see, the Milky Way arcs through the night above Seoul, South Korea. Remarkably, this urban night skyscape reveals our galaxy's faintly luminous central region and dark obscuring dust clouds in spite of the brilliant city lights. To overcome the extreme light pollution of the metropolitan area and record faint cosmic details, an infrared filter was used to capture the night scene in a single exposure. While the filter transmits predominately infrared light, it still passes some visible light to give the scene a natural appearance. The view is from Seoul's Ttukseom Hangang Park, with the Han River and a well lit railway bridge across the foreground. The 123 story Lotte World Tower looms in the distance, the tallest building in South Korea.

The Sun has just set... in the opposite side of the sky. Pictured here are anticrepuscular rays apparently converging in the east in this image of the limestone plateau in the heart of the Hyblaean Mountains of southeastern Sicily, in Italy. How were these anticrepuscular rays formed, if the Sun wasn't there? After the Sun set (in the west, as usual) its light still illuminated a cloud higher up in the sky. Partially blocked by the cloud, the sunlight produced patterns of light and shadow, crossing the sky in parallel lines. Perspective makes it look like they converge in the east, in the same way that train tracks appear to meet in the distance. This effect can also happen at sunrise, only the directions are exchanged. In rare cases, both crepuscular and anticrepuscular rays can be seen at the same time.

Why does the Sun throw stuff at us? The Sun’s surface is a churning soup of energetic electrons and ions called plasma. The motion of those charged particles creates magnetic field loops that are larger than the Earth. These loops twist, turn, and trap plasma. The featured time-lapse, taken over 2 hours on April 24th, 2026 by the Solar Dynamics Observatory, shows what happens when those magnetic fields become too stressed: they snap and expel billions of tons (trillions of kilograms) of plasma into space at millions of miles (or kilometers) per hour in what is called a coronal mass ejection (CME). The Sun releases a few CMEs each day when it is at the peak of its activity cycle, which passed in 2025. Some of these eruptions hit Earth and can disrupt power grids, disable satellites, and endanger astronauts, which is why space weather monitoring is so important.

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 seen under the spacecraft soon changed from light to dark, with the terminator of night crossing underneath. After closest approach, Voyager pivoted to see the departing moon, now visible as a diminishing crescent. In 2015, the robotic New Horizons spacecraft famously flew past Pluto, an orb of similar size to Triton. Almost Hyperspace: Random APOD Generator