Η Αστρονομική Εικόνα της Ημέρας από τη NASA
Interplanetary Earth
23/11/2024
In an interplanetary first, on July 19, 2013 Earth was photographed on the same day from two other worlds of the Solar System, innermost planet Mercury and ringed gas giant Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft then orbiting the outermost gas giant. On that same day people across planet Earth snapped many of their own pictures of Saturn. On the right, the Earth-Moon system is seen against the dark background of space as captured by the sunward MESSENGER spacecraft, then in Mercury orbit. MESSENGER took its image as part of a search for small natural satellites of Mercury, moons that would be expected to be quite dim. In the MESSENGER image, the brighter Earth and Moon are both overexposed and shine brightly with reflected sunlight. Destined not to return to their home world, both Cassini and MESSENGER have since retired from their missions of Solar System exploration.
Copyright: NASA
Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA
A Cosmic Zoo in Cepheus
17/08/2023
Sprawling emission nebulae IC 1396 and Sh2-129 mix glowing interstellar gas and dark dust clouds in this nearly 12 degree wide field of view toward the northern constellation Cepheus the King. Energized by its central star IC 1396 (left), is hundreds of light-years across and some 3,000 light-years distant. The nebula's intriguing dark shapes include a winding dark cloud popularly known as the Elephant's Trunk below and right of center. Tens of light-years long, it holds the raw material for star formation and is known to hide protostars within. Located a similar distance from planet Earth, the bright knots and swept back ridges of emission of Sh2-129 on the right suggest its popular name, the Flying Bat Nebula. Within the Flying Bat, the most recently recognized addition to this royal cosmic zoo is the faint bluish emission from Ou4, the Giant Squid Nebula. Near the lower right edge of the frame, the suggestive dark marking on the sky cataloged as Barnard 150 is also known as the dark Seahorse Nebula. Notable submissions to APOD: Perseids Meteor Shower 2023
Copyright: Yann Sainty
Arp 93: A Cosmic Embrace
16/08/2023
Locked in a cosmic embrace, two large galaxies are merging at the center of this sharp telescopic field of view. The interacting system cataloged as Arp 93 is some 200 million light-years distant toward the constellation Aquarius in planet Earth's sky. Individually the galaxies are identified as NGC 7285 (right) and NGC 7284. Their bright cores are still separated by about 20,000 light-years or so, but a massive tidal stream, a result of their ongoing gravitational interaction, extends over 200,000 light-years toward the bottom of the frame. Interacting galaxies do look peculiar, but are now understood to be common in the Universe. In fact, closer to home, the large spiral Andromeda Galaxy is known to be approaching the Milky Way. Arp 93 may well present an analog of their distant future cosmic embrace.
Copyright: Mike Selby
A Triply Glowing Night Sky over Iceland
15/08/2023
The Sun is not the quiet place it seems. It expels an unsteady stream of energetic electrons and protons known as the solar wind. These charged particles deform the Earth's magnetosphere, change paths, and collide with atoms in Earth's atmosphere, causing the generation of light in auroras like that visible in green in the image left. Earth itself is also geologically active and covered with volcanoes. For example, Fagradalsfjall volcano in Iceland, seen emitting hot gas in orange near the image center. Iceland is one of the most geologically active places on Earth. On the far right is the Svartsengi geothermal power plant which creates the famous human-made Blue Lagoon, shown emitting white gas plumes. The featured composition therefore highlights three different sky phenomena, including both natural and human-made phenomena.
Copyright: Wioleta Gorecka; Text: Natalia Lewandowska (SUNY Oswego)
The Ring Nebula from Webb
14/08/2023
The Ring Nebula (M57), is more complicated than it appears through a small telescope. The easily visible central ring is about one light-year across, but this remarkable exposure by the James Webb Space Telescope explores this popular nebula with a deep exposure in infrared light. Strings of gas, like eyelashes around a cosmic eye, become evident around the Ring in this digitally enhanced featured image in assigned colors. These long filaments may be caused by shadowing of knots of dense gas in the ring from energetic light emitted within. The Ring Nebula is an elongated planetary nebula, a type of gas cloud created when a Sun-like star evolves to throw off its outer atmosphere to become a white dwarf star. The central oval in the Ring Nebula lies about 2,500 light-years away toward the musical constellation Lyra.
Copyright: NASA
The Sombrero Galaxy in Infrared
13/08/2023
This floating ring is the size of a galaxy. In fact, it is a galaxy -- or at least part of one: the photogenic Sombrero Galaxy, one of the largest galaxies in the nearby Virgo Cluster of Galaxies. The dark band of dust that obscures the mid-section of the Sombrero Galaxy in optical light actually glows brightly in infrared light. The featured image, digitally sharpened, shows the infrared glow, recently recorded by the orbiting Spitzer Space Telescope, superposed in false-color on an existing image taken by NASA's Hubble Space Telescope in visible light. The Sombrero Galaxy, also known as M104, spans about 50,000 light years across and lies 28 million light years away. M104 can be seen with a small telescope in the direction of the constellation Virgo.
Copyright: NASA
Ghirigori - Star Scribbles
12/08/2023
It's fun to scribble on the canvas of the sky. You can use a creative photographic technique to cause the light of point-like stars to dance across a digital image by tapping lightly on the telescope while making an exposure. The result will be a squiggly line traced by the star (or two squiggles traced by binary stars) that can reveal the star's color. Colorful lines, dubbed Ghirigori, made from stars found in the northern sky constellations Bootes, Corona Borealis, Ophiucus, and Coma Berenices, are captured in this artistic mosaic. The 25 stars creating the varied and colorful squiggles are identified around the border. Of course, temperature determines the color of a star. While whitish stars tend to be close to the Sun's temperature, stars with bluer hues are hotter, and yellow and red colors are cooler than the Sun. Weekend Watch: Perseid Meteor Shower
Copyright: Paolo Palma
Messier 51 in 255 Hours
11/08/2023
An intriguing pair of interacting galaxies, M51 is the 51st entry in Charles Messier's famous catalog. Perhaps the original spiral nebula, the large galaxy with whirlpool-like spiral structure seen nearly face-on is also cataloged as NGC 5194. Its spiral arms and dust lanes sweep in front of a companion galaxy (right), NGC 5195. Some 31 million light-years distant, within the boundaries of the well-trained constellation Canes Venatici, M51 looks faint and fuzzy to the eye in direct telescopic views. But this remarkably deep image shows off stunning details of the galaxy pair's striking colors and extensive tidal debris. A collaboration of astro-imagers using telescopes on planet Earth combined over 10 days of exposure time to create this definitive galaxy portrait of M51. The image includes 118 hours of narrowband data that also reveals a vast glowing cloud of reddish ionized hydrogen gas discovered in the M51 system.
Copyright: The Deep Sky Collective
Five Meters over Mars
10/08/2023
On mission sol 872 (Earth date August 3) Ingenuity snapped this sharp image on its 54th flight above the surface of the Red Planet. During the flight the Mars Helicopter hovered about 5 meters, or just over 16 feet, above the Jezero crater floor. Tips of Ingenuity's landing legs peek over the left and right edges in the camera's field of view. Tracks visible near the upper right corner lead to the Perseverance Mars Rover, seen looking on from a distance at the top right edge of the frame. Planned as a brief "pop-up" flight, Ingenuity's 54th flight lasted less than 25 seconds. It followed Ingenuity's 53rd flight made on July 22 that resulted in an unscheduled landing.
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.