Η Αστρονομική Εικόνα της Ημέρας από τη NASA
NASA Science
09/11/2026
Does the blue nebula look like the head of a witch? The nebula is known popularly as the Witch Head Nebula because, it is said, the nebula's shape resembles a Halloween-style caricature of a witch's head. Exactly how, though, can be a topic of imaginative speculation. What is clear is that IC 2118 is about 50 light-years across and made of gas and dust that points to -- because it has been partly eroded by -- the nearby star Rigel. One of the brighter stars in the constellation Orion, Rigel lies just below the center of the featured image. The blue color of the Witch Head Nebula and is caused not only by Rigel's intense blue starlight but also because the dust grains scatter blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in planet Earth's atmosphere are molecules of nitrogen and oxygen.Tomorrow's picture: suddenly Saturn
Copyright: NASA
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
NASA Science
15/10/2026
The city lights outshine the stars in the City That Never Sleeps. Who would have thought that the Milky Way could be visible in this sky? This image was taken with a filter that blocks most visible light, capturing instead only light in the near-infrared region of the electromagnetic spectrum (with lower energy than visible light). The astrophotographer's clever setup blocks most of the light pollution from the city: old incandescent light bulbs and some neon lights are still bright in the near-infrared, but fluorescent and LED light bulbs are not. Of course, stars are also bright in the near-infrared! This image is a reminder that we all live under the same sky, and astronomy allows all of us to learn more about humanity's place in the Cosmos.
Copyright: NASA
NASA Science
14/10/2026
What a cosmic coincidence! In today’s image, Mars joins the Beehive cluster (M44 or Praesepe) below an auroral curtain and above a horizon of happy little trees near Lansjärv, Sweden. An eruption off the Sun reached Earth on October 10th, 2026 causing strong disturbances in Earth’s magnetic field. Energetic particles from the eruption collide with and energize the molecules in Earth’s atmosphere, which release that extra energy as the colorful aurora captured here. Auroras, or guovssahasat in North Sámi, is traditionally viewed with respect by the Sámi people indigenous to Sweden and other Arctic regions. Coincidentally, Mars appeared closest to the center of the Beehive cluster in the sky at the time. Although bees have been to space, the Beehive cluster is actually a swarm of young stars. Their rotation periods have helped humanity learn about how stars spin slower over time as they lose mass through their stellar winds.Tomorrow's picture: open space
Copyright: NASA
NASA Science
13/10/2026
This stairway in Chile brings you only a little bit closer to heaven. But ooh, the sky above it makes you wonder. For example, you may wonder about the dark lane of our own Milky Way galaxy rising behind the expansive Atacama Desert in Chile, the band of zodiacal light on the upper left, the green and red airglow just above the horizon, the star Spica in the zodiacal light stripe, and, at the very top on the right, the Small Magellanic Cloud galaxy. The Desert Staircase sculpture is in the foreground, and this image was timed to catch the picturesque peering perch just in front of the near-vertical Milky Way band. Upon close inspection of the horizon you can find, left to right, some Andes Mountains, the Licancabur volcano, and the town lights of San Pedro de Atacama. The featured wide-angle composite was captured in July 2025.Tomorrow's picture: open space
Copyright: NASA
NASA Science
12/10/2026
How many moons can you see? The best answer is five: four orbiting Jupiter and Luna orbiting Earth. This multi-moon picture was possible because Earth's Moon moved directly in front of Jupiter last week. The featured image is a series of exposures near alignment taken from Westchester, New York, USA. The sunlit crescent of Earth's Moon, on the lower left, is overexposed, while the Moon's night side, on the upper right, is faintly illuminated by Earthshine. Lined up nearly vertically above our Moon, listed from bottom to top, are Jupiter's bright Galilean satellites: Ganymede, Io, Callisto, and Europa. Callisto, Ganymede, and Io are larger than Earth's Moon, while Europa is only slightly smaller. NASA's robotic spacecraft Juno is currently orbiting Jupiter and has made close passes near three of these moons.Tomorrow's picture: stairway to heaven
Copyright: NASA
NASA Science
11/10/2026
Scientists are melting holes in the bottom of the world. In fact, almost 100 holes melted near the South Pole are now being used as an astronomical observatory. Astronomers with the IceCube Neutrino Observatory lowered a long string knotted with basketball-sized light detectors into each vertical lake. The water in each hole soon refreezes. The detectors attached to the strings are sensitive to blue light emitted in the surrounding clear ice. Such light results from fast-moving secondary particles liberated when high-energy neutrinos emitted by powerful processes out in the universe collide with ice molecules. IceCube has now detected many illuminating neutrinos. Pictured in 2010, one of the last of IceCube's detector strings is lowered into the freezing abyss, making IceCube the largest neutrino detector ever created. In recognition of unprecedented discoveries, it was announced earlier this week that a founding leader of the IceCube Collaboration will be awarded the Nobel Prize in Physics.Tomorrow's picture: Moons Planet
Copyright: NASA
NASA Science
10/10/2026
Tidally locked in synchronous rotation, the Moon always presents its familiar nearside to denizens of planet Earth. From lunar orbit, the Moon's farside can become familiar, though. In fact this sharp picture, a mosaic from the Lunar Reconnaissance Orbiter's wide angle camera, is centered on the lunar farside. Part of a global mosaic of over 15,000 images acquired between November 2009 and February 2011, the highest resolution version shows features at a scale of 100 meters per pixel. Surprisingly, the rough and battered surface of the farside looks very different from the nearside covered with smooth dark lunar maria. A likely explanation is that the farside crust is thicker, making it harder for molten material from the interior to flow to the surface and form dark, smooth maria.Tomorrow's picture: Sunday's Childe
Copyright: NASA
NASA Science
09/10/2026
Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet's moons in 1877. Over 9 kilometers across, Stickney is nearly half the diameter of Phobos itself, so large that the impact that blasted out the crater likely came close to shattering the tiny moon. This enhanced-color image of Stickney and surroundings was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter as it passed within some six thousand kilometers of Phobos in March of 2008. Even though the surface gravity of asteroid-like Phobos is less than 1/1000th Earth's gravity, streaks suggest loose material slid down inside the crater walls over time. Light bluish regions near the crater's rim could indicate a relatively freshly exposed surface. The origin of the curious grooves along the surface is mysterious but may be related to tidal stresses experienced by close-orbiting Phobos or the crater-forming impact itself.Tomorrow's picture: farside
Copyright: NASA
NASA Science
08/10/2026
How was the Saturn system imaged so clearly? Astrophotographer Tom Williams captured such exquisite details due to one night of exceptional atmospheric conditions above the United Kingdom. This means more than a cloudless sky. Pockets of air at different temperatures and densities move around and bend light as it travels through Earth’s atmosphere, distorting astronomy images. This is called “seeing”. Less atmospheric turbulence means clearer images. The astrophotographer reduced the impact of seeing with the lucky imaging technique: thousands of short-exposure images are taken very quickly with a high-speed camera and the clearest images are added up. Which object in this smörgåsbord interests you? Perhaps Titan or the icy stripes of Enceladus? Maybe the gaps and spokes in Saturn’s rings? Saturn's opposition, when Earth passes in between the planet and the Sun, occurred on October 4th. Due to the planet's proximity and full illumination from the Sun, now is a great time of year to observe it!Tomorrow's picture: bumpy
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.