Η Αστρονομική Εικόνα της Ημέρας από τη NASA
Galaxies in the River
11/12/2025
Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity. In fact, the practice is common in the universe and illustrated by this striking pair of interacting galaxies from the banks of the southern constellation Eridanus, The River. Located over 50 million light years away, the large, distorted spiral NGC 1532 is seen locked in a gravitational struggle with dwarf galaxy NGC 1531, a struggle the smaller galaxy will eventually lose. Seen nearly edge-on, in this sharp image spiral NGC 1532 spans about 100,000 light-years. The NGC 1532/1531 pair is thought to be similar to the well-studied system of face-on spiral and small companion known as M51.
Copyright: Vikas Chander
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Eclipse at Sunrise
03/10/2024
The second solar eclipse of 2024 began in the Pacific. On October 2nd the Moon's shadow swept from west to east, with an annular eclipse visible along a narrow antumbral shadow path tracking mostly over ocean, crossing land near the southern tip of South America, and ending in the southern Atlantic. The dramatic total annular eclipse phase is known to some as a ring of fire. Still, a partial eclipse of the Sun was experienced over a wide region. Captured at one of its earliest moments, October's eclipsed Sun is seen just above the clouds near sunrise in this snapshot. The partially eclipsed solar disk is close to the maximum eclipse as seen from Mauna Kea Observatory Visitor Center, Island of Hawaii, planet Earth. Growing Gallery: Annular Solar Eclipse 2024 October
Copyright: Wang Letian
The Large Magellanic Cloud Galaxy
02/10/2024
It is the largest satellite galaxy of our home Milky Way Galaxy. If you live in the south, the Large Magellanic Cloud (LMC) is quite noticeable, spanning about 10 degrees across the night sky, which is 20 times larger than the full moon towards the southern constellation of the dolphinfish (Dorado). Being only about 160,000 light years away, many details of the LMC's structure can be seen, such as its central bar and its single spiral arm. The LMC harbors numerous stellar nurseries where new stars are being born, which appear in pink in the featured image. It is home to the Tarantula Nebula, the currently most active star forming region in the entire Local Group, a small collection of nearby galaxies dominated by the massive Andromeda and Milky Way galaxies. Studies of the LMC and the Small Magellanic Cloud (SMC) by Henrietta Swan Leavitt led to the discovery of the period-luminosity relationship of Cepheid variable stars that are used to measure distances across the nearby universe. Survey: Color Blindness and Astronomical Images
Copyright: Ireneusz Nowak; Text: Natalia Lewandowska (SUNY Oswego)
Porphyrion: The Longest Known Black Hole Jets
01/10/2024
How far can black hole jets extend? A new record was found just recently with the discovery of a 23-million light-year long jet pair from a black hole active billions of years ago. Dubbed Porphyrion for a mythological Greek giant, the impressive jets were created by a type of black hole that does not usually create long jets -- one that is busy creating radiation from infalling gas. The featured animated video depicts what it might look like to circle around this powerful black hole system. Porphyrion is shown as a fast stream of energetic particles, and the bright areas are where these particles are impacting surrounding gas. The discovery was made using data from the Keck and Mayall (DESI) optical observatories as well as LOFAR and the Giant Metrewave Radio Telescope. The existence of these jets demonstrates that black holes can affect not only their home galaxies but far out into the surrounding universe. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Copyright: NASA
Comet Tsuchinshan-ATLAS over Mexico
30/09/2024
The new comet has passed its closest to the Sun and is now moving closer to the Earth. C/2023 A3 (Tsuchinshan–ATLAS) is currently moving out from inside the orbit of Venus and on track to pass its nearest to the Earth in about two weeks. Comet Tsuchinshan-ATLAS, pronounced "Choo-cheen-shahn At-less,", is near naked-eye visibility and easily picked up by long-exposure cameras. The comet can also now be found by observers in Earth's northern hemisphere as well as the south. The featured image was captured just a few days ago above Zacatecas, Mexico. Because clouds were obscuring much of the pre-dawn sky, the astrophotographer released a drone to take pictures from higher up, several of which were later merged to enhance the comet's visibility. Although the future brightness of comets is hard to predict, there is increasing hope that Comet Tsuchinshan-ATLAS will further brighten as it enters the early evening sky. Growing Gallery: Comet Tsuchinsan-ATLAS in 2024
Copyright: Daniel Korona
Seven Dusty Sisters
29/09/2024
Is this really the famous Pleiades star cluster? Known for its iconic blue stars, the Pleiades is shown here in infrared light where the surrounding dust outshines the stars. Here, three infrared colors have been mapped into visual colors (R=24, G=12, B=4.6 microns). The base images were taken by NASA's orbiting Wide Field Infrared Survey Explorer (WISE) spacecraft. Cataloged as M45 and nicknamed the Seven Sisters, the Pleiades star cluster is by chance situated in a passing dust cloud. The light and winds from the massive Pleiades stars preferentially repel smaller dust particles, causing the dust to become stratified into filaments, as seen. The featured image spans about 20 light years at the distance of the Pleiades, which lies about 450 light years distant toward the constellation of the Bull (Taurus).
Copyright: NASA
Rocket Eclipse at Sunset
28/09/2024
Shockwaves ripple across the glare as a launch eclipses the setting Sun in this exciting close-up. Captured on September 17, the roaring Falcon 9 rocket carried European Galileo L13 navigation satellites to medium Earth orbit after a lift-off from Cape Canaveral on Florida's space coast. The Falcon 9 booster returned safely to Earth about 8.5 minutes later, notching the 22nd launch and landing for the reusable workhorse launch vehicle. But where did it land? Just Read the Instructions.
Copyright: Ben Cooper
Stellar Streams in the Local Universe
27/09/2024
The twenty galaxies arrayed in these panels are part of an ambitious astronomical survey of tidal stellar streams. Each panel presents a composite view; a deep, inverted image taken from publicly available imaging surveys of a field that surrounds a nearby massive galaxy image. The inverted images reveal faint cosmic structures, star streams hundreds of thousands of light-years across, that result from the gravitational disruption and eventual merger of satellite galaxies in the local universe. Such surveys of mergers and gravitational tidal interactions between massive galaxies and their dwarf satellites are crucial guides for current models of galaxy formation and cosmology. Of course, the detection of stellar streams in the neighboring Andromeda Galaxy and our own Milky Way also offers spectacular evidence for ongoing satellite galaxy disruption within our more local galaxy group.
Copyright: NASA
The Great Globular Cluster in Hercules
26/09/2024
In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shows itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Sharp telescopic views like this one reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter. Approaching the cluster core, upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. The deep, wide-field image also reveals distant background galaxies including NGC 6207 at the upper left, and faint, foreground Milky Way dust clouds known to some as integrated flux nebulae.
Copyright: Jan Beckmann, Julian Zoller, Lukas Eisert, Wolfgang Hummel
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.