Awkward and angular looking, Apollo 17's lunar module Challenger was designed for flight in the near vacuum of space. Digitally enhanced and reprocessed, this picture taken from Apollo 17's command module America shows Challenger's ascent stage in lunar orbit. Small reaction control thrusters are at the sides of the moonship with the bell of the ascent rocket engine underneath. The hatch that allowed access to the lunar surface is seen at the front, with a round radar antenna at the top. Mission commander Gene Cernan is clearly visible through the triangular window. This spaceship performed gracefully, landing on the Moon and returning the Apollo astronauts to the orbiting command module in December of 1972. So where is Challenger now? While its descent stage remains at the Apollo 17 landing site in the Taurus-Littrow valley, the ascent stage pictured was intentionally crashed nearby after being jettisoned from the command module prior to the astronauts' return to planet Earth.
Copyright: NASA
Along a narrow path that mostly avoided landfall, the shadow of the New Moon raced across planet Earth's southern hemisphere on April 20 to create a rare annular-total or hybrid solar eclipse. A mere 62 seconds of totality could be seen though, when the dark central lunar shadow just grazed the North West Cape, a peninsula in western Australia. From top to bottom these panels capture the beginning, middle, and end of that fleeting total eclipse phase. At start and finish, solar prominences and beads of sunlight stream past the lunar limb. At mid-eclipse the central frame reveals the sight only easily visible during totality and most treasured by eclipse chasers, the magnificent corona of the active Sun. Of course eclipses tend to come in pairs. On May 5, the next Full Moon will just miss the dark inner part of Earth's shadow in a penumbral lunar eclipse.
Copyright: Gwenaël Blanck
Spanning light-years, this suggestive shape known as the Seahorse Nebula appears in silhouette against a rich, luminous background of stars. Seen toward the royal northern constellation of Cepheus, the dusty, obscuring clouds are part of a Milky Way molecular cloud some 1,200 light-years distant. It is also listed as Barnard 150 (B150), one of 182 dark markings of the sky cataloged in the early 20th century by astronomer E. E. Barnard. Packs of low mass stars are forming within, but their collapsing cores are only visible at long infrared wavelengths. Still, the colorful stars of Cepheus add to this pretty, galactic skyscape.
Copyright: Jeff Herman
On some nights the sky is the best show in town. On this night, auroras ruled the sky, and the geomagnetic storm that created this colorful sky show originated from an increasingly active Sun. Surprisingly, since the approaching solar CME the day before had missed the Earth, it was not expected that this storm would create auroras. In the foreground, two happily surprised aurora hunters contemplate the amazing and rapidly changing sky. Regardless of forecasts, though, auroras were reported in the night skies of Earth not only in the far north, but as far south as New Mexico, USA. As captured in a wide-angle image above Saariselkä in northern Finnish Lapland, a bright aurora was visible with an unusually high degree of detail, range of colors, and breadth across the sky. The vivid yellow, green, red and purple auroral colors are caused by oxygen and nitrogen atoms high in Earth's atmosphere reacting to incoming electrons. Open Science: Browse 3,000+ codes in the Astrophysics Source Code Library
Copyright: Juan Carlos Casado
Would you like to see a total eclipse of the Sun? If so, do any friends or relatives live near the path of next April's eclipse? If yes again, then you might want to arrange a well-timed visit. Next April 8, the path of a total solar eclipse will cross North America from western Mexico to eastern Canada, entering the USA in southern Texas and exiting in northern Maine. All of North America will experience the least a partial solar eclipse. Featured here is a map of the path of totality. Many people who have seen a total solar eclipse tell stories about it for the rest of their lives. As a warmup, an annular solar eclipse will be visible later this year -- in mid-October.
Copyright: NASA
What's that red ring in the sky? Lightning. The most commonly seen type of lightning involves flashes of bright white light between clouds. Over the past 50 years, though, other types of upper-atmospheric lightning have been confirmed, including red sprites and blue jets. Less well known and harder to photograph is a different type of upper atmospheric lightning known as ELVES. ELVES are thought to be created when an electromagnetic pulse shoots upward from charged clouds and impacts the ionosphere, causing nitrogen molecules to glow. The red ELVES ring pictured had a radius of about 350 km and was captured in late March about 100 kilometers above Ancona, Italy. Years of experience and ultra-fast photography were used to capture this ELVES -- which lasted only about 0.001 second.
Copyright: Valter Binotto
Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured here, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes. The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousands of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale. In the center, two stars orbit inside a gaseous disk 10 times the orbit of Pluto. The expelled envelope of the dying star breaks out from the disk creating the bipolar appearance. Much remains unknown about the physical processes that cause and shape planetary nebulae.
Copyright: NASA
A composite of images captured about a week apart from mid August 2022 through late March 2023, this series traces the retrograde motion of ruddy-colored Mars. Progressing from lower right to upper left Mars makes a Z-shaped path as it wanders past the Pleiades and Hyades star clusters, through the constellation Taurus in planet Earth's night sky. Seen about every two years, Mars doesn't actually reverse the direction of its orbit to trace out the Z-shape though. Instead, the apparent backwards or retrograde motion with respect to the background stars is a reflection of the orbital motion of Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. High in northern hemisphere skies the Red Planet was opposite the Sun and at its closest and brightest on December 8, near the center of the frame. Seen close to Mars, a popular visitor to the inner Solar System, comet ZTF (C/2022 E3), was also captured on two dates, February 10 and February 16.
Copyright: Tunc Tezel
Sharp telescopic views of NGC 3628 show a puffy galactic disk divided by dark dust lanes. Of course, this portrait of the magnificent, edge-on spiral galaxy puts some astronomers in mind of its popular moniker, the Hamburger Galaxy. It also reveals a small galaxy nearby (below), likely a satellite of NGC 3628, and a very faint but extensive tidal tail. The drawn out tail stretches for about 300,000 light-years, even beyond the left edge of the frame. NGC 3628 shares its neighborhood in the local universe with two other large spirals M65 and M66 in a grouping otherwise known as the Leo Triplet. Gravitational interactions with its cosmic neighbors are likely responsible for creating the tidal tail, as well as the extended flare and warp of this spiral's disk. The tantalizing island universe itself is about 100,000 light-years across and 35 million light-years away in the northern springtime constellation Leo.
Copyright: Mike Selby
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.