Αστρονομική Εικόνα της Ημέρας από τη NASA

Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA

An Artificial Comet

30/12/2025

Yes, but can your comet tail do this? No, and what you are seeing is not the tail of a comet. The picture features a cleverly overlayed time-lapse sequence of a group of satellites orbiting Earth together in June. Specifically, these are Starlink communications satellites in low Earth orbit reflecting back sunlight before sunrise to Inner Mongolia, China. Although the satellites appear to the human eye as points, the 20-second-long camera exposures caused them to appear as short streaks. Currently there are over 9000 Starlinks in orbit, with more being launched nearly every week. Other satellite constellations are also being planned. Explore the Universe: Random APOD Generator

M1: The Crab Nebula

29/12/2025

This is the mess that is left when a star explodes. The Crab Nebula, the result of a supernova seen in 1054 AD, is filled with mysterious filaments. The filaments are not only tremendously complex but appear to have less mass than expelled in the original supernova and a higher speed than expected from a free explosion. The featured image was taken by an amateur astronomer in Leesburg, Florida, USA over three nights last month. It was captured in three primary colors but with extra detail provided by specific emission by hydrogen gas. The Crab Nebula spans about 10 light years. In the Nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second. Explore the Universe: Random APOD Generator

NGC 1898: Globular Cluster in the Large Magellanic Cloud

28/12/2025

Jewels don't shine this bright -- only stars do. And almost every spot in this jewel-box of an image from the Hubble Space Telescope is a star. Now, some stars are more red than our Sun, and some more blue -- but all of them are much farther away. Although it takes light about 8 minutes to reach Earth from the Sun, NGC 1898 is so far away that it takes light about 160,000 years to get here. This huge ball of stars, NGC 1898, is called a globular cluster and resides in the central bar of the Large Magellanic Cloud (LMC) -- a satellite galaxy of our Milky Way Galaxy. The featured multi-colored image includes light from the infrared to the ultraviolet and was taken to help determine if the stars of NGC 1898 all formed at the same time or at different times. There are increasing indications that most globular clusters formed stars in stages, and that, in particular, stars from NGC 1898 formed shortly after ancient encounters with the Small Magellanic Cloud (SMC) and our Milky Way Galaxy. Space Telescopes Live: Where are Hubble and Webb looking right now?

Apollo 17's Moonship

27/12/2025

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.

3I/ATLAS Flyby

26/12/2025

Attention grabbing interstellar visitor 3I/ATLAS made its not-so-close flyby of our fair planet on December 19 at a distance of 1.8 astronomical units. That's about 900 light-seconds. Still, this deep exposure captures the comet from another star system as it gently swept across a faint background of stars in the constellation Leo about 4 days earlier, on the night of December 15. Though faint, colors emphasized in the image data, show off the comet's yellowish dust tail and bluish ion tail along with a greenish tinged coma. And even while scrutinized by arrays of telescopes and spacecraft from planet Earth, 3I ATLAS is headed out of the Solar System. It's presently moving outward along a hyperbolic trajectory at about 64 kilometers per second relative to the Sun, too fast to be bound the Sun's gravity.

Unicorn, Fox Fur and Christmas Tree

25/12/2025

A star forming region cataloged as NGC 2264, this beautiful but complex arrangement of interstellar gas and dust is about 2,700 light-years distant in the faint but fanciful constellation Monoceros, the Unicorn. Seen toward the celestial equator and near the plane of our Milky Way galaxy, the seasonal skyscape mixes reddish emission nebulae excited by energetic light from newborn stars with dark interstellar dust clouds. Where the otherwise obscuring dust clouds lie close to the hot, young stars, they also reflect starlight, forming blue reflection nebulae. In fact, bright variable star S Monocerotis is immersed in a blue-tinted haze near center. Arrayed with a simple triangular outline above S Monocerotis, the stars of NGC 2264 are popularly known as the Christmas Tree star cluster. Carved by energetic starlight, the Cone Nebula sits upside down at the apex of this cosmic Christmas tree while the dusty, convoluted pelt of glowing gas and dust under the tree is called the Fox Fur Nebula. This rich telescopic frame spans about 1.5 degrees or 3 full moons on the sky top to bottom, covering nearly 80 light-years at the distance of NGC 2264.

Mystery: Little Red Dots in the Early Universe

24/12/2025

What are these little red dots (LRDs)? Nobody knows. Discovered only last year, hundreds of LRDs have now been found by the James Webb Space Telescope in the early universe. Although extremely faint, LRDs are now frequently identified in deep observations made for other purposes. A wide-ranging debate is raging about what LRDs may be and what importance they may have. Possible origin hypotheses include accreting supermassive black holes inside clouds of gas and dust, bursts of star formation in young dust-reddened galaxies, and dark matter powered gas clouds. The highlighted images show six nearly featureless LRDs listed under the JWST program that found them, and z, a distance indicator called cosmological redshift. Additionally, searches are underway in our nearby universe to try to find whatever previous LRDs might have become today.

Red Sprites and Circular Elves Lightning over Italy

23/12/2025

What's happening 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 tentacled red sprites and ringed ELVES. Although both last only a small fraction of a second, sprites are brighter and easier to photograph than their more common electrical-discharge cousins. ELVES are rapidly expanding rings that are thought to be created when an electromagnetic pulse shoots upward from charged clouds and impacts the ionosphere, causing nitrogen molecules to glow. Capturing either form of lightning takes patience and experience -- capturing them both together, since they usually occur separately, is rare. The featured image is a frame from a video recorded from Possagno, Italy late last month above a distant thunderstorm over the Adriatic Sea.

Η Αστρονομική Εικόνα της Ημέρας από τη NASA

Cygnus and the Solitary Tree

18/03/2026