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. Usually spotted at high latitudes in summer months, the night shining clouds have made a strong showing so far during the short northern summer nights. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash.
Copyright: Clear Skies
Globular star cluster 47 Tucanae is a jewel of the southern sky. Also known as NGC 104, it roams the halo of our Milky Way Galaxy along with some 200 other globular star clusters. The second brightest globular cluster (after Omega Centauri) as seen from planet Earth, 47 Tuc lies about 13,000 light-years away. It can be spotted with the naked-eye close on the sky to the Small Magellanic Cloud in the constellation of the Toucan. The dense cluster is made up of hundreds of thousands of stars in a volume only about 120 light-years across. Red giant stars on the outskirts of the cluster are easy to pick out as yellowish stars in this sharp telescopic portrait. Tightly packed globular cluster 47 Tuc is also home to a star with the closest known orbit around a black hole.
Copyright: Marco Lorenzi
What's different about this galaxy? Very little, which makes the Spanish Dancer galaxy, NGC 1566, one of the most typical and photogenic spirals on the sky. There is something different about this galaxy image, though, because it is a diagonal combination of two images: one by the Hubble Space Telescope on the upper left, and the other by the James Webb Space Telescope on the lower right. The Hubble image was taken in ultraviolet light and highlights the locations of bright blue stars and dark dust along the galaxy's impressive spiral arms. In contrast, the Webb image was taken in infrared light and highlights where the same dust emits more light than it absorbed. In the rollover image, the other two sides of these images are revealed. Blinking between the two images shows which stars are particularly hot because they glow brighter in ultraviolet light, and the difference between seemingly empty space and infrared-glowing dust. Image Crunching Opportunity: Take NASA's Astrophoto Challenge
Copyright: NASA, ESA, CSA, STScI, J. Lee (STScI), T. Williams (Oxford), R. Chandar (UToledo), D. Calzetti (UMass), PHANGS Team
What's happening in the core of the Carina Nebula? Stars are forming, dying, and leaving an impressive tapestry of dark dusty filaments. The entire Carina Nebula, cataloged as NGC 3372, spans over 300 light years and lies about 8,500 light-years away in the constellation of Carina. The nebula is composed predominantly of hydrogen gas, which emits the pervasive red and orange glows seen mostly in the center of this highly detailed featured image. The blue glow around the edges is created primarily by a trace amount of glowing oxygen. Young and massive stars located in the nebula's center expel dust when they explode in supernovas. Eta Carinae, the most energetic star in the nebula's center, was one of the brightest stars in the sky in the 1830s, but then faded dramatically. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Copyright: Carlos Taylor
Stars are forming in the gigantic dust pillar called the Cone Nebula. Cones, pillars, and majestic flowing shapes abound in stellar nurseries where natal clouds of gas and dust are buffeted by energetic winds from newborn stars. The Cone Nebula, a well-known example, lies within the bright galactic star-forming region NGC 2264. The Cone was captured in unprecedented detail in this close-up composite of several observations from the Earth-orbiting Hubble Space Telescope. While the Cone Nebula, about 2,500 light-years away in Monoceros, is around 7 light-years long, the region pictured here surrounding the cone's blunted head is a mere 2.5 light-years across. In our neck of the galaxy that distance is just over half way from our Sun to its nearest stellar neighbors in the Alpha Centauri star system. The massive star NGC 2264 IRS, seen by Hubble's infrared camera in 1997, is the likely source of the wind sculpting the Cone Nebula and lies off the top of the image. The Cone Nebula's reddish veil is produced by dust and glowing hydrogen gas.
Copyright: NASA
Apollo 14's Lunar Module Antares landed on the Moon on February 5, 1971. Toward the end of the stay astronaut Ed Mitchell snapped a series of photos of the lunar surface while looking out a window, assembled into this detailed mosaic by Apollo Lunar Surface Journal editor Eric Jones. The view looks across the Fra Mauro highlands to the northwest of the landing site after the Apollo 14 astronauts had completed their second and final walk on the Moon. Prominent in the foreground is their Modular Equipment Transporter, a two-wheeled, rickshaw-like device used to carry tools and samples. Near the horizon at top center is a 1.5 meter wide boulder dubbed Turtle rock. In the shallow crater below Turtle rock is the long white handle of a sampling instrument, thrown there javelin-style by Mitchell. Mitchell's fellow moonwalker and first American in space, Alan Shepard, also used a makeshift six iron to hit two golf balls. One of Shepard's golf balls is just visible as a white spot below Mitchell's javelin.
Copyright: NASA
This cosmic view shows off an otherwise faint emission nebula IC 410, captured under clear Netherlands skies with telescope and narrowband filters. Above and right of center you can spot two remarkable inhabitants of the interstellar pond of gas and dust, known as the tadpoles of IC 410. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars. Formed in the interstellar cloud a mere 4 million years ago, the intensely hot, bright cluster stars energize the glowing gas. Globules composed of denser cooler gas and dust, the tadpoles are around 10 light-years long and are likely sites of ongoing star formation. Sculpted by stellar winds and radiation their heads are outlined by bright ridges of ionized gas while their tails trail away from the cluster's central young stars. IC 410 and embedded NGC 1893 lie some 10,000 light-years away, toward the nebula-rich constellation Auriga.
Copyright: Sander de Jong
Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the faint but heated constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax Cluster of galaxies. This sharp color image shows the intense, reddish star forming regions near the ends of the galaxy's central bar and along its spiral arms. Seen in fine detail, obscuring dust lanes cut across the galaxy's bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole.
Copyright: Jean-Baptiste Auroux
What does Orion rising look like to a camera? During this time of the year, the famous constellation is visible to the southeast just after sunset. From most Earthly locations, Orion's familiar star pattern, highlighted by the three-stars-in-a-row belt stars, rises sideways. An entire section of the night sky that includes Orion was photographed rising above Śnieżka, a mountain on the border between Poland and the Czech Republic. The long duration exposure sequence brings up many faint features including the Orion and Flame Nebulas, both encompassed by the curving Barnard's Loop. The featured wide-angle camera composite also captured night sky icons including the blue Pleiades star cluster at the image top and the red Rosette Nebula to the left of Orion. Famous stars in the frame include Sirius, Betelgeuse, Rigel and Aldebaran. Orion will appear successively higher in the sky at sunset during the coming months.
Copyright: Marcin Ślipko
Η Αστρονομική Εικόνα της Ημέρας από τη NASA (NASA Astronomy Picture of the Day) είναι μια δωρεάν υπηρεσία που παρέχει καθημερινά μια εντυπωσιακή εικόνα από το σύμπαν, την λήψη της οποίας έχει πραγματοποιήσει κάποιος από τους αστρονόμους της NASA ή από κάποιον από τους δορυφόρους ή τα τηλεσκόπια που η NASA λειτουργεί. Οι εικόνες που εμφανίζονται καλύπτουν μια ευρεία γκάμα από θέματα, συμπεριλαμβανομένων των αστερισμών, των γαλαξιών, των πλανητικών συστημάτων, των κομητών, των αστρικών σωμάτων και των παρατηρητηρίων. Κάθε εικόνα συνοδεύεται από μια σύντομη εξήγηση και πληροφορίες σχετικά με το τι παρατηρείται στην εικόνα.