Η Αστρονομική Εικόνα της Ημέρας από τη NASA
Gemini Meteors over Snow Capped Mountains
15/12/2025
Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Gemini. That is why the major meteor shower in December is known as the Geminids -- because shower meteors all appear to come from a radiant toward Gemini. Three dimensionally, however, sand-sized debris expelled from the unusual asteroid 3200 Phaethon follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the constellation of Gemini. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Gemini. Featured here is a composite of many images taken over the past few days through dark skies from Slovakia and capturing the snow-covered peaks of the Belianske Tatra mountains Numerous bright meteor streaks from the Geminids meteor shower are visible. Orion is visible above the horizon, while the bright star nearest the radiant is Castor. APOD Review: RJN's Night Sky Network Lecture
Copyright: Tomáš Slovinský
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Galaxies in the Furnace
04/12/2025
An example of violence on a cosmic scale, enormous elliptical galaxy NGC 1316 lies about 75 million light-years away toward Fornax, the southern constellation of the Furnace. Investigating the startling sight, astronomers suspect the giant galaxy of colliding with smaller neighbor NGC 1317 seen just right of the large galaxy's center, producing far flung star streams in loops and shells. Light from their close encounter would have reached Earth some 100 million years ago. In the sharp telescopic image, the central regions of NGC 1316 and NGC 1317 appear separated by over 100,000 light-years. Complex dust lanes visible within also indicate that NGC 1316 is itself the result of a merger of galaxies in the distant past. Found on the outskirts of the Fornax galaxy cluster, NGC 1316 is known as Fornax A. One of the visually brightest of the Fornax cluster galaxies it is one of the strongest and largest celestial radio sources with radio emission extending well beyond this one degree wide field-of-view.
Copyright: Simone Curzi
Visualization: Near a Black Hole and Disk
03/12/2025
What would it look like to plunge into a monster black hole? This image from a supercomputer visualization shows the entire sky as seen from a simulated camera plunging toward a 4-million-solar-mass black hole, similar to the one at the center of our galaxy. The camera lies about 16 million kilometers from the black hole’s event horizon and is moving inward at 62% the speed of light. Thanks to gravity’s funhouse effects, the starry band of the Milky Way appears both as a compact loop at the top of this view and as a secondary image stretching across the bottom. Move the cursor over the image for additional explanations. Visualizations like this allow astronomers to explore black holes in ways not otherwise possible.
Copyright: NASA
M77: Spiral Galaxy with an Active Center
02/12/2025
What's happening in the center of nearby spiral galaxy M77? The face-on galaxy lies a mere 47 million light-years away toward the constellation of the Sea Monster (Cetus). At that estimated distance, this gorgeous island universe is about 100 thousand light-years across. Also known as NGC 1068, its compact and very bright core is well studied by astronomers exploring the mysteries of supermassive black holes in active Seyfert galaxies. M77's active core glows bright at x-ray, ultraviolet, visible, infrared, and radio wavelengths. The featured sharp image of M77 was taken by the Hubble Space Telescope. The image shows details of the spiral's winding spiral arms as traced by obscuring red dust clouds and blue star clusters, all circling the galaxy's bright white luminous center. Free APOD Lecture in Phoenix: Wednesday, December 10 at 7 pm
Copyright: NASA
3I ATLAS: Tails of an Interstellar Comet
01/12/2025
How typical is our Solar System? Studying 3I/ATLAS, a comet just passing through, is providing clues. Confirmed previous interstellar visitors include an asteroid, a comet, a meteor, and a gas wind dominated by hydrogen and helium. Comet 3I/ATLAS appears relatively normal when compared to Solar System comets, therefore providing more evidence that our Solar System is a somewhat typical star system. For example, Comet 3I/ATLAS has a broadly similar chemical composition and ejected dust. The featured image was captured last week from Texas and shows a green coma, a wandering blue-tinted ion tail likely deflected by our Sun's wind, and a slight anti-tail, all typical cometary attributes. The comet, visible with a telescope, passed its closest to the Sun in late October and will pass its closest to the Earth in mid-December, after which it will return to interstellar space and never return. Explore the Universe: Random APOD Generator
Copyright: Victor Sabet & Julien De Winter
The Surface of Titan from Huygens
30/11/2025
If you could stand on Titan -- what would you see? The featured color view from Titan gazes across an unfamiliar and distant landscape on Saturn's largest moon. The scene was recorded by ESA's Huygens probe in 2005 after a 2.5-hour descent through a thick atmosphere of nitrogen laced with methane. Bathed in an eerie orange light at ground level, rocks strewn about the scene could well be composed of water and hydrocarbons frozen solid at an inhospitable temperature of negative 179 degrees C. The large light-toned rock below and left of center is only about 15 centimeters across and lies 85 centimeters away. The saucer-shaped spacecraft is believed to have penetrated about 15 centimeters into a place on Titan's surface that had the consistency of wet sand or clay. Huygen's batteries enabled the probe to take and transmit data for more than 90 minutes after landing. Titan's bizarre chemical environment may bear similarities to planet Earth's before life evolved.
Copyright: NASA
Moon Games
29/11/2025
This is not a screen from a video game. Nestled below the tree-line, the small mountain church does look like it might be hiding from Moon though. In the well-composed telephoto snapshot, taken on November 23, the church walls are partly reflecting light from terrestrial flood lights. Of course, the Moon is reflecting light from the Sun. At any given time the Sun illuminates fully half of the Moon's surface, also known as the lunar dayside, but on that night only a sliver of its sunlit surface was visible. About three days after New Moon, the Moon was in a waxing crescent phase. The single exposure was captured shortly after sunset in skies near Danta di Cadore, northern Italy, planet Earth.
Copyright: Giorgia Hofer
NGC 6888: The Crescent Nebula
28/11/2025
NGC 6888, also known as the Crescent Nebula, is a about 25 light-years across, a cosmic bubble blown by winds from its central, massive star. This deep telescopic image includes narrowband image data, to isolate light from hydrogen and oxygen atoms. The oxygen atoms produce the blue-green hue that seems to enshroud the nebula's detailed folds and filaments. Visible within the nebula, NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. In fact, the Crescent Nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life, this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away.
Copyright: Greg Bass
Portrait of NGC 1055
27/11/2025
Big, beautiful spiral galaxy NGC 1055 is a dominant member of a small galaxy group a mere 60 million light-years away toward the aquatically intimidating constellation Cetus. Seen edge-on, the island universe spans over 100,000 light-years, a little larger than our own Milky Way galaxy. The colorful, spiky stars decorating this cosmic portrait of NGC 1055 are in the foreground, well within the Milky Way. But telltale pinkish star forming regions and young blue star clusters are scattered through winding dust lanes along the distant galaxy's thin disk. With a smattering of even more distant background galaxies, the deep image also reveals a boxy halo that extends far above and below the central bulge and disk of NGC 1055. The halo itself is laced with faint, narrow structures, and could represent the mixed and spread out debris from a satellite galaxy disrupted by the larger spiral some 10 billion years ago.
Copyright: John Hayes
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.