Η Αστρονομική Εικόνα της Ημέρας από τη NASA
A Message from Earth
29/03/2026
What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of an upgrade to the Arecibo Observatory - then the largest single radio telescope in the world - a string of 1's and 0's representing the diagram was sent. This attempt at extraterrestrial communication was mostly ceremonial - humanity regularly broadcasts radio and television signals out into space accidentally. Even were this message received, M13 is so far away we would have to wait almost 50,000 years to hear an answer. The featured message gives a few simple facts about humanity and its knowledge: from left to right are numbers from one to ten, atoms including hydrogen and carbon, some interesting molecules, DNA, a human with description, basics of our Solar System, and basics of the sending telescope. Several searches for extraterrestrial intelligence are currently underway. Explore the Universe: Random APOD Generator
Copyright: NASA
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
Portrait of NGC 1055
15/03/2024
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 the telltale pinkish star forming regions 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: Dave Doctor
Moon Pi and Mountain Shadow
14/03/2024
What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude. That's opposite the Sun in planet Earth's sky. Rising as the Sun set on March 9, 2020, only an hour or so after the moment of its full phase, this orange tinted and slightly flattened Moon still looked full. It was photographed opposite the setting Sun from Teide National Park on the Canary Island of Tenerife. Also opposite the setting Sun, seen from near the Teide volcano peak about 3,500 meters above sea level, is the mountain's rising triangular shadow extending into Earth's dense atmosphere. Below the distant ridge line on the left are the white telescope domes of Teide Observatory. Again Pi radians from the Sun, on March 25 the Full Moon will dim slightly as it glides through Earth's outer shadow in a penumbral lunar eclipse.
Copyright: El Cielo de Canarias
The Seagull Nebula
13/03/2024
A broad expanse of glowing gas and dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker: the Seagull Nebula. This portrait of the cosmic bird covers a 2.5-degree wide swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation of the Big Dog (Canis Major). Of course, the region includes objects with other catalog designations: notably NGC 2327, a compact, dusty emission and reflection nebula with an embedded massive star that forms the bird's head. Likely part of a larger shell structure swept up by successive supernova explosions, the broad Seagull Nebula is cataloged as Sh2-296 and IC 2177. The prominent bluish arc below and right of center is a bow shock from runaway star FN Canis Majoris. Dominated by the reddish glow of atomic hydrogen, this complex of gas and dust clouds with other stars of the Canis Majoris OB1 association spans over 200 light-years at the Seagull Nebula's estimated 3,800 light-year distance. Almost Hyperspace: Random APOD Generator
Copyright: Gianni Lacroce
A Galaxy-Shaped Rocket Exhaust Spiral
12/03/2024
What's that over the horizon? What may look like a strangely nearby galaxy is actually a normal rocket's exhaust plume -- but unusually backlit. Although the SpaceX Falcon 9 rocket was launched from Vandenberg Space Force Base in California, USA, its burned propellant was visible over a much wider area, with the featured photograph being taken from Akureyri, Iceland. The huge spaceship was lifted off a week ago, and the resulting spectacle was captured soon afterward with a single 10-second smartphone exposure, before it quickly dissipated. Like noctilucent clouds, the plume's brightness is caused by the Twilight Effect, where an object is high enough to be illuminated by the twilight Sun, even when the observer on the ground experiences the darkness of night. The spiral shape is caused by the Falcon rocket reorienting to release satellites in different directions. Stars and faint green and red aurora appear in the background of this extraordinary image.
Copyright: Seung Hye Yang
A Full Plankton Moon
11/03/2024
What glows in the night? This night featured a combination of usual and unusual glows. Perhaps the most usual glow was from the Moon, a potentially familiar object. The full Moon's nearly vertical descent results from the observer being near Earth's equator. As the Moon sets, air and aerosols in Earth's atmosphere preferentially scatter out blue light, making the Sun-reflecting satellite appear reddish when near the horizon. Perhaps the most unusual glow was from the bioluminescent plankton, likely less familiar objects. These microscopic creatures glow blue, it is thought, primarily to surprise and deter predators. In this case, the glow was caused primarily by plankton-containing waves crashing onto the beach. The image was taken on Soneva Fushi Island, Maldives just over one year ago. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Copyright: Petr Horálek / Institute of Physics in Opava
A Total Eclipse at the End of the World
10/03/2024
Would you go to the end of the world to see a total eclipse of the Sun? If you did, would you be surprised to find someone else there already? In 2003, the Sun, the Moon, Antarctica, and two photographers all lined up in Antarctica during an unusual total solar eclipse. Even given the extreme location, a group of enthusiastic eclipse chasers ventured near the bottom of the world to experience the surreal momentary disappearance of the Sun behind the Moon. One of the treasures collected was the featured picture -- a composite of four separate images digitally combined to realistically simulate how the adaptive human eye saw the eclipse. As the image was taken, both the Moon and the Sun peeked together over an Antarctic ridge. In the sudden darkness, the magnificent corona of the Sun became visible around the Moon. Quite by accident, another photographer was caught in one of the images checking his video camera. Visible to his left are an equipment bag and a collapsible chair. A more easily visible solar eclipse will occur in just under four weeks and be visible from a long, thin swath of North America.
Copyright: Fred Bruenjes (moonglow.net)
Comet Pons-Brooks in Northern Spring
09/03/2024
As spring approaches for northern skygazers, Comet 12P/Pons-Brooks is growing brighter. Currently visible with small telescopes and binoculars, the Halley-type comet could reach naked eye visibility in the coming weeks. Seen despite a foggy atmosphere, the comet's green coma and long tail hover near the horizon in this well-composed deep night skyscape from Revuca, Slovakia recorded on March 5. M31, also known as the Andromeda galaxy, and bright yellowish star Mirach, beta star of the constellation Andromeda, hang in the sky above the comet. The Andromeda galaxy is some 2.5 million light-years beyond the Milky Way. Comet Pons-Brooks is a periodic visitor to the inner Solar System and less than 14 light-minutes away. Reaching its perihelion on April 21, this comet should be visible in the sky during the April 8 total solar eclipse.
Copyright: Petr Horálek
The Tarantula Zone
08/03/2024
The Tarantula Nebula, also known as 30 Doradus, is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud. About 180 thousand light-years away, it's the largest, most violent star forming region known in the whole Local Group of galaxies. The cosmic arachnid sprawls across this magnificent view, an assembly of image data from large space- and ground-based telescopes. Within the Tarantula (NGC 2070), intense radiation, stellar winds, and supernova shocks from the central young cluster of massive stars cataloged as R136 energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. In fact, the frame includes the site of the closest supernova in modern times, SN 1987A, at lower right. The rich field of view spans about 2 degrees or 4 full moons in the southern constellation Dorado. But were the Tarantula Nebula closer, say 1,500 light-years distant like the Milky Way's own star forming Orion Nebula, it would take up half the sky.
Copyright: Robert Gendler
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.