Astronomy Picture of the Day

🌌The Galaxy Between Two Friends On an August night two friends enjoyed this view after a day's hike on the Plateau d'Emparis in the French Alps. At 2400 meters altitude the sky was clear. Light from a setting moon illuminates the foreground captured in the simple vertical panorama of images. Along the plane of our Milky Way galaxy stars of Cassiopeia and Perseus shine along the panorama's left e ...

© Valerio Avitabile

🌌The Dark Seahorse in Cepheus Light-years across, this suggestive shape known as the Seahorse Nebula appears in silhouette against a rich, luminous background of stars. Seen toward the royal northern constellation of Cepheus, the dusty, obscuring clouds are part of a Milky Way molecular cloud some 1,200 light-years distant. It is also listed as Barnard 150 (B150), one of 182 dark markings of the ...

© Dan Bartlett

🌌NGC 147 and NGC 185 Dwarf galaxies NGC 147 (left) and NGC 185 stand side by side in this sharp telescopic portrait. The two are not-often-imaged satellites of M31, the great spiral Andromeda Galaxy, some 2.5 million light-years away. Their separation on the sky, less than one degree across a pretty field of view, translates to only about 35 thousand light-years at Andromeda's distance, but Andr ...

© Wissam Ayoub

🌌The Horsehead and Flame Nebulas The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the orange emission nebula at the far right of the featured picture. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed ...

🌌SN Requiem: A Supernova Seen Three Times So Far We've seen this same supernova three times -- when will we see it a fourth? When a distant star explodes in a supernova, we're lucky if we see it even once. In the case of AT 2016jka ("SN Requiem"), because the exploding star happened to be lined up behind the center of a galaxy cluster (MACS J0138 in this case), a comparison of Hubble Space Teles ...

© Xie Jie

🌌A Waterfall and the Milky Way The dream was to capture both the waterfall and the Milky Way together. Difficulties included finding a good camera location, artificially illuminating the waterfall and the surrounding valley effectively, capturing the entire scene with numerous foreground and background shots, worrying that fireflies would be too distracting, keeping the camera dry, and avoiding ...

© Tom AbelRalf KaehlerKIPACSLACAMNH

🌌Dark Matter in a Simulated Universe Is our universe haunted? It might look that way on this dark matter map. The gravity of unseen dark matter is the leading explanation for why galaxies rotate so fast, why galaxies orbit clusters so fast, why gravitational lenses so strongly deflect light, and why visible matter is distributed as it is both in the local universe and on the cosmic microwave bac ...

© Göran Strand

🌌A Rorschach Aurora If you see this as a monster's face, don't panic. It's only pareidolia, often experienced as the tendency to see faces in patterns of light and shadow. In fact, the startling visual scene is actually a 180 degree panorama of Northern Lights, digitally mirrored like inkblots on a folded piece of paper. Frames used to construct it were captured on a September night from the mid ...

© Leo Shatz

🌌Haunting the Cepheus Flare Spooky shapes seem to haunt this dusty expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds visible in dimly reflected starlight. Far from your own neighborhood, they lurk above the plane of the Milky Way at the edge of the Cepheus Flare molecular cloud complex some 1,200 light-years away. Over 2 light-ye ...

© John Chumack

🌌Mirach's Ghost As far as ghosts go, Mirach's Ghost isn't really that scary. Mirach's Ghost is just a faint, fuzzy galaxy, well known to astronomers, that happens to be seen nearly along the line-of-sight to Mirach, a bright star. Centered in this star field, Mirach is also called Beta Andromedae. About 200 light-years distant, Mirach is a red giant star, cooler than the Sun but much larger and ...

© Howard Trottier

🌌NGC 6995: The Bat Nebula Do you see the bat? It haunts this cosmic close-up of the eastern Veil Nebula. The Veil Nebula itself is a large supernova remnant, the expanding debris cloud from the death explosion of a massive star. While the Veil is roughly circular in shape and covers nearly 3 degrees on the sky toward the constellation of the Swan (Cygnus), NGC 6995, known informally as the Bat N ...

🌌Jupiter Rotates Observe the graceful twirl of our Solar System's largest planet. Many interesting features of Jupiter's enigmatic atmosphere, including dark belts and light zones, can be followed in detail. A careful inspection will reveal that different cloud layers rotate at slightly different speeds. The famous Great Red Spot is not visible at first -- but soon rotates into view. Other small ...

© Michael Abramyan

🌌Road to the Galactic Center Does the road to our galaxy's center go through Monument Valley? It doesn't have to, but if your road does -- take a picture. In this case, the road is US Route 163 and iconic buttes on the Navajo National Reservation populate the horizon. The band of Milky Way Galaxy stretches down from the sky and appears to be a continuation of the road on Earth. Filaments of dust ...

🌌Halloween and the Ghost Head Nebula Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere). With a modern calendar however, even though Halloween occurs next week, the real cross-quarter day ...

🌌3D Bennu Put on your red/blue glasses and float next to asteroid 101955 Bennu. Shaped like a spinning toy top with boulders littering its rough surface, the tiny Solar System world is about one Empire State Building (less than 500 meters) across. Frames used to construct this 3D anaglyph were taken by PolyCam on the OSIRIS_REx spacecraft on December 3, 2018 from a distance of about 80 kilometer ...

© Jose Mtanous

🌌A Comet and a Crab This pretty field of view spans over 2 degrees or 4 full moons on the sky, filled with stars toward the constellation Taurus, the Bull. Above and right of center in the frame you can spot the faint fuzzy reddish appearance of Messier 1 (M1), also known as the Crab Nebula. M1 is the first object in 18th century comet hunter Charles Messier's famous catalog of things which are ...

© Nik Szymanek

🌌SH2-308: The Dolphin-Head Nebula Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,000 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, ...

© John Kraus

🌌Lucy Launches to Eight Asteroids Why would this mission go out as far as Jupiter -- but then not visit Jupiter? Lucy's plan is to follow different leads about the origin of our Solar System than can be found at Jupiter -- where Juno now orbits. Jupiter is such a massive planet that its gravity captures numerous asteroids that orbit the Sun ahead of it -- and behind. These trojan asteroids forme ...

🌌Palomar 6: Globular Star Cluster Where did this big ball of stars come from? Palomar 6 is one of about 200 globular clusters of stars that survive in our Milky Way Galaxy. These spherical star-balls are older than our Sun as well as older than most stars that orbit in our galaxy's disk. Palomar 6 itself is estimated to be about 12.5 billion years old, so old that it is close to -- and so constr ...

© Dario Giannobile

🌌Earthshine Moon over Sicily Why can we see the entire face of this Moon? When the Moon is in a crescent phase, only part of it appears directly illuminated by the Sun. The answer is earthshine, also known as earthlight and the da Vinci glow. The reason is that the rest of the Earth-facing Moon is slightly illuminated by sunlight first reflected from the Earth. Since the Earth appears near full ...

🌌The Einstein Cross Gravitational Lens Most galaxies have a single nucleus -- does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image. The central cloverleaf is rather light emitted from a background quasar. The gravitational field of the visible foreground galaxy breaks light from this distant quas ...

© Gianni Sarcone

🌌The Moona Lisa Only natural colors of the Moon in planet Earth's sky appear in this creative visual presentation. Arranged as pixels in a framed image, the lunar disks were photographed at different times. Their varying hues are ultimately due to reflected sunlight affected by changing atmospheric conditions and the alignment geometry of Moon, Earth, and Sun. Here, the darkest lunar disks are t ...

© Mike Selby

🌌NGC 289: Swirl in the Southern Sky About 70 million light-years distant, gorgeous spiral galaxy NGC 289 is larger than our own Milky Way. Seen nearly face-on, its bright core and colorful central disk give way to remarkably faint, bluish spiral arms. The extensive arms sweep well over 100 thousand light-years from the galaxy's center. At the lower right in this sharp, telescopic galaxy portrait ...

© Ignacio Diaz Bobillo

🌌NGC 7293: The Helix Nebula A mere seven hundred light years from Earth, toward the constellation Aquarius, a sun-like star is dying. Its last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. A total of 90 hours of exposure time have gone in to creating this expansive view of t ...

© Yizhou Zhang

🌌NGC 7822: Cosmic Question Mark It may look like a huge cosmic question mark, but the big question really is how does the bright gas and dark dust tell this nebula's history of star formation. At the edge of a giant molecular cloud toward the northern constellation Cepheus, the glowing star forming region NGC 7822 lies about 3,000 light-years away. Within the nebula, bright edges and dark shapes ...

© Hao Qin

🌌Fireball over Lake Louise What makes a meteor a fireball? First of all, everyone agrees that a fireball is an exceptionally bright meteor. Past that, the International Astronomical Union defines a fireball as a meteor brighter than apparent magnitude -4, which corresponds (roughly) to being brighter than any planet -- as well as bright enough to cast a human-noticeable shadow. Pictured, an astr ...