Η Αστρονομική Εικόνα της Ημέρας από τη NASA
A Quadruple Alignment over Italy
04/03/2025
Why does this Moon look so unusual? A key reason is its vivid red color. The color is caused by the deflection of blue light by Earth's atmosphere -- the same reason that the daytime sky appears blue. The Moon also appears unusually distorted. Its strange structuring is an optical effect arising from layers in the Earth's atmosphere that refract light differently due to sudden differences in temperature or pressure. A third reason the Moon looks so unusual is that there is, by chance, an airplane flying in front. The featured picturesque gibbous Moon was captured about two weeks ago above Turin, Italy. Our familiar hovering sky orb was part of an unusual quadruple alignment that included two historic ground structures: the Sacra di San Michele on the near hill and Basilica of Superga just beyond. Your Sky Surprise: What picture did APOD feature on your friend's birthday? (post 1995)
Copyright: Valerio Minato
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Blue Ghost on the Moon
03/03/2025
There's a new lander on the Moon. Yesterday Firefly Aerospace's Blue Ghost executed the first-ever successful commercial lunar landing. During its planned 60-day mission, Blue Ghost will deploy several NASA-commissioned scientific instruments, including PlanetVac which captures lunar dust after creating a small whirlwind of gas. Blue Ghost will also host the telescope LEXI that captures X-ray images of the Earth's magnetosphere. LEXI data should enable a better understanding of how Earth's magnetic field protects the Earth from the Sun's wind and flares. Pictured, the shadow of the Blue Ghost lander is visible on the cratered lunar surface, while the glowing orb of the planet Earth hovers just over the horizon. Goals for future robotic Blue Ghost landers include supporting lunar astronauts in NASA's Artemis program, with Artemis III currently scheduled to land humans back on the Moon in 2027.
Copyright: NASA
Blue Ghost to the Moon
01/03/2025
With spacecraft thrusters at top center, the rugged surface of the Moon lies below the Blue Ghost lander in this space age video frame. The view of the lunar far side was captured by the Firefly Aerospace lunar lander on February 24, following a maneuver to circularize its orbit about 100 kilometers above the lunar surface. The robotic lunar lander is scheduled to touch down tomorrow, Sunday, March 2, at 3:34am Eastern Time in the Mare Crisium impact basin on the lunar near side. In support of the Artemis campaign, Blue Ghost is set to deliver science and technology experiments to the Moon, part of NASA's Commercial Lunar Payload Services program. Blue Ghost's mission on the surface is planned to operate during the lunar daylight hours at the landing site, about 14 Earth days.
Copyright: NASA
Athena to the Moon
28/02/2025
Planet Earth hangs in the background of this space age selfie. The snapshot was captured by the IM-2 Nova-C lander Athena, just after stage separation following its February 26 launch to the Moon. A tall robotic lander, Athena is scheduled to touch down on Thursday, March 6, in Mons Mouton, a plateau near the Moon’s South Pole. The intended landing site is in the central portion of one of the Artemis 3 potential landing regions. Athena carries rovers and experiments as part of NASA's Commercial Lunar Payload Services program, including a drill intended to explore beneath the lunar surface in a search for evidence of frozen water. It also carries a propulsive drone dubbed the Micro Nova Hopper. After release to the lunar surface, the autonomous drone is intended to hop into a nearby crater and send science data back to the lander.
Copyright: NASA
Open Star Clusters M35 and NGC 2158
27/02/2025
Framed in this single, starry, telescopic field of view are two open star clusters, M35 and NGC 2158. Located within the boundaries of the constellation Gemini, they do appear to be side by side. Its stars concentrated toward the upper right, M35 is relatively nearby, though. M35 (also cataloged as NGC 2168) is a mere 2800 light-years distant, with 400 or so stars spread out over a volume about 30 light-years across. Bright blue stars frequently distinguish younger open clusters like M35, whose age is estimated at 150 million years. At lower left, NGC 2158 is about four times more distant than M35 and much more compact, shining with the more yellowish light of a population of stars over 10 times older. In general, open star clusters are found along the plane of our Milky Way Galaxy. Loosely gravitationally bound, their member stars tend to be dispersed over billions of years as the open star clusters orbit the galactic center.
Copyright: Evan Tsai
Einstein Ring Surrounds Nearby Galaxy Center
26/02/2025
Do you see the ring? If you look very closely at the center of the featured galaxy NGC 6505, a ring becomes evident. It is the gravity of NGC 6505, the nearby (z = 0.042) elliptical galaxy that you can easily see, that is magnifying and distorting the image of a distant galaxy into a complete circle. To create a complete Einstein ring there must be perfect alignment of the nearby galaxy's center and part of the background galaxy. Analysis of this ring and the multiple images of the background galaxy help to determine the mass and fraction of dark matter in NGC 6505's center, as well as uncover previously unseen details in the distorted galaxy. The featured image was captured by ESA's Earth-orbiting Euclid telescope in 2023 and released earlier this month.
Copyright: ESA, NASA, Euclid Consortium; Processing: J.-C. Cuillandre, G. Anselmi, T. Li
M41: The Little Beehive Star Cluster
25/02/2025
Why are there so many bright blue stars? Stars are usually born in clusters, and the brightest and most massive of these stars typically glow blue. Less-bright, non-blue stars like our Sun surely also exist in this M41 star cluster but are harder to see. A few bright orange-appearing red giant stars are visible. The red-light filaments are emitted by diffuse hydrogen gas, a color that was specifically filtered and enhanced in this image. In a hundred million years or so, the bright blue stars will have exploded in supernovas and disappeared, while the slightly different trajectories of the fainter stars will cause this picturesque open cluster to disperse. Similarly, billions of years ago, our own Sun was likely born into a star cluster like M41, but it has long since drifted apart from its sister stars. The featured image was captured over four hours with Chilescope T2 in Chile.
Copyright: Xinran Li
Light Pillar over Erupting Etna
24/02/2025
Can a lava flow extend into the sky? No, but light from the lava flow can. One effect is something quite unusual -- a volcanic light pillar. More typically, light pillars are caused by sunlight and so appear as a bright column that extends upward above a rising or setting Sun. Alternatively, other light pillars -- some quite colorful -- have been recorded above street and house lights. This light pillar, though, was illuminated by the red light emitted by the glowing magma of an erupting volcano. The volcano is Italy's Mount Etna, and the featured image was captured with a single shot during an early morning in mid-February. Freezing temperatures above the volcano's lava flow created ice-crystals either in the air above the volcano or in condensed water vapor expelled by Mount Etna. These ice crystals -- mostly flat toward the ground but fluttering -- then reflected away light from the volcano's caldera.
Copyright: Davide Caliò
Saturn in Infrared from Cassini
23/02/2025
Saturn looks slightly different in infrared light. Bands of clouds show great structure, including long stretching storms. Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn's North Pole. Each side of the dark hexagon spans roughly the width of our Earth. The hexagon's existence was not predicted, and its origin and likely stability remain a topics of research. Saturn's famous rings circle the planet and cast shadows below the equator. The featured image was taken by the robotic Cassini spacecraft in 2014 in several infrared colors. In 2017 September, the Cassini mission was brought to a dramatic conclusion when the spacecraft was directed to dive into the ringed giant. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
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.