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Η Αστρονομική Εικόνα της Ημέρας από τη NASA

A Message from Earth

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

Deep Nebulas: From Seagull to California

Deep Nebulas: From Seagull to California

23/01/2024

How well do you know the night sky? OK, but how well can you identify famous sky objects in a very deep image? Either way, here is a test: see if you can find some well-known night-sky icons in a deep image filled with faint nebulosity. This image contains the Pleiades star cluster, Barnard's Loop, Horsehead Nebula, Orion Nebula, Rosette Nebula, Cone Nebula, Rigel, Jellyfish Nebula, Monkey Head Nebula, Flaming Star Nebula, Tadpole Nebula, Aldebaran, Simeis 147, Seagull Nebula and the California Nebula. To find their real locations, here is an annotated image version. The reason this task might be difficult is similar to the reason it is initially hard to identify familiar constellations in a very dark sky: the tapestry of our night sky has an extremely deep hidden complexity. The featured composite reveals some of this complexity in a mosaic of 28 images taken over 800 hours from dark skies over Arizona, USA.

Copyright: Alistair Symon

Shadows of Mountain and Moon

Shadows of Mountain and Moon

22/01/2024

Can the Moon and a mountain really cast similar shadows? Yes, but the division between light and dark does not have to be aligned. Pictured, a quarter moon was captured above the mountain Grivola in Italy in early October of 2022. The Sun is to the right of the featured picturesque landscape, illuminating the right side of the Moon in a similar way that it illuminates the right side of the mountain. This lunar phase is called "quarter" because the lit fraction visible from Earth is one quarter of the entire lunar surface. Digital post-processing of this single exposure gave both gigantic objects more prominence. Capturing the terminator of this quarter moon in close alignment with nearly vertical mountain ridge required careful timing because the Earth rotates once a day.

Copyright: Enzo Massa Micon

The Upper Michigan Blizzard of 1938

The Upper Michigan Blizzard of 1938

21/01/2024

Yes, but can your blizzard do this? In the Upper Peninsula of Michigan's Storm of the Century in 1938, some snow drifts reached the level of utility poles. Nearly a meter of new and unexpected snow fell over two days in a storm that started 86 years ago this week. As snow fell and gale-force winds piled snow to surreal heights, many roads became not only impassable but unplowable; people became stranded, cars, school buses and a train became mired, and even a dangerous fire raged. Two people were killed and some students were forced to spend several consecutive days at school. The featured image was taken by a local resident soon after the storm. Although all of this snow eventually melted, repeated snow storms like this help build lasting glaciers in snowy regions of our planet Earth.

Copyright: NASA

Falcon Heavy Boostback Burn

Falcon Heavy Boostback Burn

20/01/2024

The December 28 night launch of a Falcon Heavy rocket from Kennedy Space Center in Florida marked the fifth launch for the rocket's reusable side boosters. About 2 minutes 20 seconds into the flight, the two side boosters separated from the rocket's core stage. Starting just after booster separation, this three minute long exposure captures the pair's remarkable boostback burns, maneuvers executed prior to their return to landing zones on planet Earth. While no attempt was made to recover the Falcon Heavy's core stage, both side boosters landed successfully and can be flown again. The four previous flights for these side boosters included last October's launch of NASA's asteroid-bound Psyche mission.

Copyright: Dennis Huff

Jupiter over 2 Hours and 30 Minutes

Jupiter over 2 Hours and 30 Minutes

19/01/2024

Jupiter, our Solar System's ruling gas giant, is also the fastest spinning planet, rotating once in less than 10 hours. The gas giant doesn't rotate like a solid body though. A day on Jupiter is about 9 hours and 56 minutes long at the poles, decreasing to 9 hours and 50 minutes near the equator. The giant planet's fast rotation creates strong jet streams, separating its clouds into planet girdling bands of dark belts and bright zones. You can easily follow Jupiter's rapid rotation in this sharp sequence of images from the night of January 15, all taken with a camera and small telescope outside of Paris, France. Located just south of the equator, the giant planet's giant storm system, also known as the Great Red Spot, can be seen moving left to right with the planet's rotation. From lower left to upper right, the sequence spans about 2 hours and 30 minutes.

Copyright: NASA

Northern Lights from the Stratosphere

Northern Lights from the Stratosphere

18/01/2024

Northern lights shine in this night skyview from planet Earth's stratosphere, captured on January 15. The single, 5 second exposure was made with a hand-held camera on board an aircraft above Winnipeg, Canada. During the exposure, terrestrial lights below leave colorful trails along the direction of motion of the speeding aircraft. Above the more distant horizon, energetic particles accelerated along Earth's magnetic field at the planet's polar regions excite atomic oxygen to create the shimmering display of Aurora Borealis. The aurora's characteristic greenish hue is generated at altitudes of 100-300 kilometers and red at even higher altitudes and lower atmospheric densities. The luminous glow of faint stars along the plane of our Milky Way galaxy arcs through the night, while the Andromeda galaxy extends this northern skyview to extragalactic space. A diffuse hint of Andromeda, the closest large spiral to the Milky Way, can just be seen to the upper left.

Copyright: Ralf Rohner

America and the Sea of Serenity

America and the Sea of Serenity

17/01/2024

Get out your red/blue glasses and check out this stereo view of another world. The scene was recorded by Apollo 17 mission commander Eugene Cernan on December 11, 1972, one orbit before descending to land on the Moon. The stereo anaglyph was assembled from two photographs (AS17-147-22465, AS17-147-22466) captured from his vantage point on board the Lunar Module Challenger as he and Dr. Harrison Schmitt flew over Apollo 17's landing site in the Taurus-Littrow Valley. The broad, sunlit face of the mountain dubbed South Massif rises near the center of the frame, above the dark floor of Taurus-Littrow to its left. Piloted by Ron Evans, the Command Module America is visible in orbit in the foreground against the South Massif's peak. Beyond the mountains, toward the lunar limb, lies the Moon's Mare Serenitatis. Four astronauts will venture around the Moon and back again on the Artemis II mission, scheduled for launch no earlier than September 2025.

Copyright: Gene Cernan

The Orion You Can Almost See

The Orion You Can Almost See

16/01/2024

Do you recognize this constellation? Although it is one of the most recognizable star groupings on the sky, this is a more full Orion than you can see -- an Orion only revealed with long exposure digital camera imaging and post- processing. Here the cool red giant Betelgeuse takes on a strong orange tint as the brightest star on the upper left. Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse on the lower right, and Bellatrix at the upper right. Lined up in Orion's belt are three stars all about 1,500 light-years away, born from the constellation's well-studied interstellar clouds. Just below Orion's belt is a bright but fuzzy patch that might also look familiar -- the stellar nursery known as Orion's Nebula. Finally, just barely visible to the unaided eye but quite striking here is Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer E. E. Barnard.

Copyright: Michele Guzzini

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.