Big, beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo but appears as only a faint smudge in the eyepiece of a small telescope. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably deep and detailed galaxy portrait, a telescopic image that spans an area about the angular size of a full moon. In it, the giant galaxy's elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past smaller satellite galaxy NGC 6744A at the upper left. NGC 6744's galactic companion is reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.
Copyright: John Hayes
No, the Moon is not a bow, and no, it did not shoot out a plane like an arrow. What is pictured is a chance superposition. The plane's contrail would normally appear white, but the large volume of air toward the rising Sun preferentially knocked away blue light, not only making the sky blue, but giving the reflected trail a bright red hue. Far in the distance, well behind the plane, the crescent Moon also appears slightly reddened. Captured early last month from Bolton, UK, the featured image was taken so soon after sunrise that the plane was sunlit from below, as was its contrail. Within minutes, unfortunately, the impromptu sky show ended. The plane moved out of sight. The Moon kept rising but became harder to see through a brightening sky. And the contrail gradually dispersed.
Copyright: Juned Patel
You can take a subway ride to visit this observatory in Beijing, China but you won't find any telescopes there. Starting in the 1400s astronomers erected devices at the Beijing Ancient Observatory site to enable them to accurately measure and track the positions of naked-eye stars and planets. Some of the large, ornate astronomical instruments are still standing. You can even see stars from the star observation platform today, but now only the very brightest celestial beacons are visible against the city lights. In this time series of exposures from a camera fixed to a tripod to record graceful arcing startrails, the brightest trail is actually the Moon. Its broad arc is seen behind the ancient observatory's brass armillary sphere. Compare this picture from the Beijing Ancient Observatory taken in September 2023 to one taken in 1895.
Copyright: Jeff Dai
The core of the Milky Way is rising beyond the Chilean mountain-top La Silla Observatory in this deep night skyscape. Seen toward the constellation Sagittarius, our home galaxy's center is flanked on the left, by the European Southern Observatory's New Technology Telescope which pioneered the use of active optics to accurately control the shape of large telescope mirrors. To the right stands the ESO 3.6-meter Telescope, home of the exoplanet hunting HARPS and NIRPS spectrographs. Between them, the galaxy's central bulge is filled with obscuring clouds of interstellar dust, bright stars, clusters, and nebulae. Prominent reddish hydrogen emission from the star-forming Lagoon Nebula, M8, is near center. The Trifid Nebula, M20, combines blue light of a dusty reflection nebula with reddish emission just left of the cosmic Lagoon. Both are popular stops on telescopic tours of the galactic center. The composited image is a stack of separate exposures for ground and sky made in April 2023, all captured consecutively with the same framing and camera equipment.
Copyright: José Rodrigues
On flight day 13 (November 28, 2022) of the Artemis I mission, the Orion spacecraft reached its maximum distance from its home world. Over 430,000 kilometers from Earth in a distant retrograde orbit, Orion surpassed the record for most distant spacecraft designed to carry humans. That record was previously set in 1970 during the Apollo 13 mission to the Moon. Both Earth and Moon are in the same field of view in this video frame from Orion on Artemis I mission flight day 13. The planet and its large natural satellite even appear about the same apparent size from the uncrewed spacecraft's perspective.
Copyright: NASA
Could there be a tornado inside another tornado? In general, no. OK, but could there be a tornado inside a wider dust devil? No again, for one reason because tornados comes down from the sky, but dust devils rise up from the ground. What is pictured is a landspout, an unusual type of tornado known to occur on the edge of a violent thunderstorm. The featured landspout was imaged and identified in Kansas, USA, in June 2019 by an experienced storm chaser. The real tornado is in the center, and the outer sheath was possibly created by large dust particles thrown out from the central tornado. So far, the only planet known to create tornados is Earth, although tornado-like activity has been found on the Sun and dust devils are common on Mars. Almost Hyperspace: Random APOD Generator
Copyright: Brad Hannon
What does the largest moon in the Solar System look like? Jupiter's moon Ganymede, larger than even Mercury and Pluto, has an icy surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges. The cause of the grooved terrain remains a topic of research, with a leading hypothesis relating it to shifting ice plates. Ganymede is thought to have an ocean layer that contains more water than Earth -- and might contain life. Like Earth's Moon, Ganymede keeps the same face towards its central planet, in this case Jupiter. The featured image was captured in 2021 by NASA's robotic Juno spacecraft when it passed by the immense moon. The close pass reduced Juno's orbital period around Jupiter from 53 days to 43 days. Juno continues to study the giant planet's high gravity, unusual magnetic field, and complex cloud structures. Follow Podcasts about APOD's Images: on YouTube
Copyright: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill;
This eagle ray glides across a cosmic sea. Officially cataloged as SH2-63 and LBN 86, the dark nebula is composed of gas and dust that just happens to appear shaped like a common ocean fish. The interstellar dust nebula appears light brown as it blocks and reddens visible light emitted behind it. Dark nebulas glow primarily in infrared light, but also reflect visible light from surrounding stars. The dust in dark nebulas is usually sub-millimeter chunks of carbon, silicon, and oxygen, frequently coated with frozen carbon monoxide and nitrogen. Dark nebulas are also known as molecular clouds because they also contain relatively high amounts of molecular hydrogen and larger molecules. Previously unnamed, the here dubbed Eagle Ray Nebula is normally quite dim but has been imaged clearly over 20-hours through dark skies in Chile. Follow APOD on: Discord
Copyright: Vikas Chander
Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. In 2016, though, ESA's Rosetta spacecraft not only imaged a jet emerging from Comet 67P/Churyumov-Gerasimenko, but flew right through it. Featured is a telling picture showing a bright plume emerging from a small circular dip bounded on one side by a 10-meter high wall. Analyses of Rosetta data show that the jet was composed of both dust and water-ice. The rugged but otherwise unremarkable terrain indicates that something likely happened far under the porous surface to create the plume. This image was taken about two months before Rosetta's mission ended with a controlled impact onto Comet 67P's surface.
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.