Η Αστρονομική Εικόνα της Ημέρας από τη NASA
NASA Science
28/10/2026
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Copyright: NASA
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
NASA Science
27/10/2026
Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises upfrom the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Normally too dim to be seen, they may become visible just after sunset during the summer when illuminated by sunlight from below the horizon. Noctilucent clouds are the highest clouds and are known more technically as polar mesospheric clouds. Featured here as they appeared in early August, a network of blue noctilucent clouds was captured in the distant sky above a field of green grass near Linköping, Sweden, with trees in stark silhouette across the horizon. Much about noctilucent clouds has been discovered only in the past two decades, while how they form and evolve remains a topic of active research.Tomorrow's picture: round and round
Copyright: NASA
NASA Science
26/10/2026
The Great Nebula in Orion, an immense, nearby starbirth region, is one the most famous of all astronomical nebulas. Here, glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away. In the featured deep image in assigned colors highlighted by emission in hydrogen, wisps and sheets of dust and gas are particularly evident. The Great Nebula in Orion can be found with the unaided eye near the easily identifiable belt of three stars in the popular constellation Orion. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries. These nurseries contain much hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds. Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.Tomorrow's picture: open space
Copyright: NASA
NASA Science
25/10/2026
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 how visible matter is distributed. The featured image from the American Museum of Natural History's Hayden Planetarium Space Show, Dark Universe, highlights one example of how pervasive dark matter might haunt our universe. In this frame from a detailed computer simulation, complex filaments of dark matter, shown in black, are strewn about the universe like spider webs, while the relatively rare clumps of familiar baryonic matter are colored orange. These simulations are good statistical matches to astronomical observations. In what is perhaps a scarier turn of events, dark matter -- although quite strange and in an unknown form -- is no longer thought to be the strangest source of gravity in the universe. That honor now falls to dark energy, a more uniform source of repulsive gravity that seems to now dominate the expansion of the entire universe.Tomorrow's picture: Orion the Great
Copyright: NASA
NASA Science
24/10/2026
This Rosetta spacecraft selfie was snapped on October 7th, 2014. At the time the comet-chasing spacecraft was about 472 million kilometers from planet Earth, but only 16 kilometers from the surface of comet 67P/Churyumov-Gerasimenko. Looming beyond the spacecraft near the top of the frame, dust and gas stream away from the comet's curious double-lobed nucleus. Bright sunlight glints off one of Rosetta's 14 meter long solar arrays. In fact, two exposures, one short and one long, were combined to record the dramatic high contrast scene using the CIVA camera system on Rosetta's still-attached Philae lander. Its chosen primary landing site was on the visible hemisphere of the smaller lobe of the nucleus. This was the last image from Philae's camera before the lander separated from Rosetta on November 12. Shortly after separation Philae took another image looking back toward the orbiter and began its descent to the nucleus of the comet.Tomorrow's picture: dark matters
Copyright: NASA
NASA Science
23/10/2026
Looking toward the north from Mullion, New South Wales, Australia, the Andromeda Galaxy never gets more than a few degrees above the horizon. During the southern hemisphere spring, Andromeda is highest in the sky around midnight though. And in this telephoto scene from October 10/11, multiple exposures were used to reveal the spiral galaxy in tantalizing detail as it climbed above rolling Australian hills. Also known as M31, the Andromeda Galaxy is one of the brightest objects in the Messier catalog, but is only visible to the unaided eye as a small, faint, fuzzy patch. Digitally tracked and stacked frames were combined with a foreground shot in the deep astro-image composite to reveal the galaxy's greater extent in planet Earth's night. In the springtime night skyscape,the closest large spiral galaxy spans nearly 6 full moons.Tomorrow's picture: pixels in space
Copyright: NASA
NASA Science
22/10/2026
Star light, star bright: is there a green star out tonight? Other than the Sun, all stars are so far from Earth that they appear as points in the sky. They are mostly white, but sometimes noticeably red or blue. This color typically relates to the temperature: blue stars are hotter than red stars. What about other colors? The featured image is an illustration showing WD J1330+6435, a white dwarf star, surrounded by an accretion disk with gas and rocks orbiting the star. White dwarfs are small, faint stars that are left over when a star like the Sun exhausts its nuclear fuel. Astronomers recently found that some white dwarf stars, despite their name, would appear yellow, green, cyan, pink, or purple. In these cases, trace elements that were accreted to these stars interact with the stellar atmosphere and shift its normally white color. But, alas! I wish I may, I wish I might, but they are too faint to see tonight...
Copyright: NASA
NASA Science
21/10/2026
Jinkies, look at all those ghosts! It took 100 hours of observation and a special oxygen filter for today’s image to capture three faint nebulas hidden in the Cassiopeia constellation. IC 59 and IC 63, the original Ghosts of Cassiopeia, haunt the region near multi-star system γ Cassiopeia. Energetic light from γ Cassiopeia causes the hydrogen gas in IC 59 and 63 to glow red. Their dust reflects and scatters some blue-ish white starlight. Newly discovered Objects 1, 2, and 3 appear as blue phantoms, revealing the presence of ionized oxygen. But ionized by what? Like at the bow of a speeding boat, γ Cassiopeia may be piling up material as the system moves through interstellar gas and dust. It follows that Object 3 may be the compressed and heated oxygen of that bow shock. Object 1 could be a planetary nebula if a central white dwarf is identified. The origins of these astronomical apparitions remain a mystery to be solved.Tomorrow's picture: it's not easy being green
Copyright: NASA
NASA Science
20/10/2026
This is an unusual rainbow. For one thing, the rainbow is not complete, appearing only in a sunlit fan -- but that by itself is not very unusual. What is most unusual is the fake location of the Sun. The Sun appears to be toward the front, just below those hills -- but it is not. That is not how rainbows work. Rainbows involve a backward reflection from falling rain, so that the Sun must really be behind you. In this case, gaps between clouds near the setting Sun allowed rays to cross the entire sky and appear to converge in front, an unusual phenomenon called anticrepuscular rays. The photo was taken with a phone last week at sunset in Presenzano, Italy. The seemingly reverse rainbow was noticed when hanging up laundry.Tomorrow's picture: open space
Copyright: NASA
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.