Αστρονομική Εικόνα της Ημέρας από τη NASA

Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA

Structure in the Tail of Comet 12P/Pons-Brooks

16/02/2024

Heading for its next perihelion passage on April 21, Comet 12P/Pons-Brooks is growing brighter. The greenish coma of this periodic Halley-type comet has become relatively easy to observe in small telescopes. But the bluish ion tail now streaming from the active comet's coma and buffeted by the solar wind, is faint and difficult to follow. Still, in this image stacked exposures made on the night of February 11 reveal the fainter tail's detailed structures. The frame spans over two degrees across a background of faint stars and background galaxies toward the northern constellation Lacerta. Of course Comet 12P's April 21 perihelion passage will be only two weeks after the April 8 total solar eclipse, putting the comet in planet Earth's sky along with a totally eclipsed Sun.

NGC 253: Dusty Island Universe

15/02/2024

Shiny NGC 253 is one of the brightest spiral galaxies visible, and also one of the dustiest. Some call it the Silver Coin Galaxy for its appearance in small telescopes, or just the Sculptor Galaxy for its location within the boundaries of the southern constellation Sculptor. Discovered in 1783 by mathematician and astronomer Caroline Herschel, the dusty island universe lies a mere 10 million light-years away. About 70 thousand light-years across, NGC 253 is the largest member of the Sculptor Group of Galaxies, the nearest to our own Local Group of Galaxies. In addition to its spiral dust lanes, tendrils of dust seem to be rising from its galactic disk laced with young star clusters and star forming regions in this colorful galaxy portrait. The high dust content accompanies frantic star formation, earning NGC 253 the designation of a starburst galaxy. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center.

A January Wolf Moon

13/02/2024

Did you see the full moon last month? During every month, on average, a full moon occurs in the skies over planet Earth. This is because the Moon takes a month to complete another orbit around our home planet, goes through all of its phases, and once again has its entire Earth-facing half lit by reflected sunlight. Many indigenous cultures give each full moon a name, and this past full moon's names include the Ice Moon, the Stay at Home Moon, and the Quiet Moon. Occurring in January on the modern western calendar, several cultures have also named the most recent full moon the Wolf Moon, in honor of the famous howling animal. Featured here above the Italian Alps mountains, this past Wolf Moon was captured in combined long and short exposure images. The image is striking because, to some, the surrounding clouds appear as a wolf's mouth ready to swallow the Wolf Moon, while others see the Moon as a wolf's eye.

HFG1 & Abell 6: Planetary Nebulae

12/02/2024

Planetary nebulae like Heckathorn-Fesen-Gull 1 (HFG1) and Abell 6 in the constellation Cassiopeia are remnants from the last phase of a medium sized star like our Sun. In spite of their shapes, planetary nebulae have nothing in common with actual planets. Located in the bottom left part of the featured photo, HFG1 was created by the binary star system V664 Cas, which consists of a white dwarf star and a red giant star. Both stars orbit their center of mass over about half an Earth day. Traveling with the entire nebula at a speed about 300 times faster than the fastest train on Earth, V664 Cas generates a bluish arc shaped shock wave. The wave interacts most strongly with the surrounding interstellar medium in the areas where the arc is brightest. After roughly 10,000 years, planetary nebulae become invisible due to a lack of ultraviolet light being emitted by the stars that create them. Displaying beautiful shapes and structures, planetary nebulae are highly desired objects for astrophotographers.

Rocket Plume Shadow Points to the Moon

11/02/2024

Why would the shadow of a rocket's launch plume point toward the Moon? In early 2001 during a launch of the space shuttle Atlantis, the Sun, Earth, Moon, and rocket were all properly aligned for this photogenic coincidence. First, for the space shuttle's plume to cast a long shadow, the time of day must be either near sunrise or sunset. Only then will the shadow be its longest and extend all the way to the horizon. Finally, during a Full Moon, the Sun and Moon are on opposite sides of the sky. Just after sunset, for example, the Sun is slightly below the horizon, and, in the other direction, the Moon is slightly above the horizon. Therefore, as Atlantis blasted off, just after sunset, its shadow projected away from the Sun toward the opposite horizon, where the Full Moon happened to be. Almost Hyperspace: Random APOD Generator

The Shadow of Ingenuity's Damaged Rotor Blade

10/02/2024

On January 18, 2024, during its 72nd flight in the thin Martian atmosphere, autonomous Mars Helicopter Ingenuity rose to an altitude of 12 meters (40 feet) and hovered for 4.5 seconds above the Red Planet. Ingenuity's 72nd landing was a rough one though. During descent it lost contact with the Perseverance rover about 1 meter above the Martian surface. Ingenuity was able to transmit this image after contact was re-established, showing the shadow of one of its rotor blades likely damaged during landing. And so, after wildly exceeding expectations during over 1,000 days of exploring Mars, the history-making Ingenuity has ended its flight operations. Nicknamed Ginny, Mars Helicopter Ingenuity became the first aircraft to achieve powered, controlled flight on another planet on April 19, 2021. Before launch, a small piece of material from the lower-left wing of the Wright Brothers Flyer 1, the first aircraft to achieve powered, controlled flight on planet Earth, was fixed to the underside of Ingenuity's solar panel.

When Roses Aren't Red

09/02/2024

Not all roses are red of course, but they can still be very pretty. Likewise, the beautiful Rosette Nebula and other star forming regions are often shown in astronomical images with a predominately red hue, in part because the dominant emission in the nebula is from hydrogen atoms. Hydrogen's strongest optical emission line, known as H-alpha, is in the red region of the spectrum. But the beauty of an emission nebula need not be appreciated in red light alone. Other atoms in the nebula are also excited by energetic starlight and produce narrow emission lines as well. In this close-up view of the Rosette Nebula, narrowband images are mapped into broadband colors to show emission from Sulfur atoms in red, Hydrogen in green, and Oxygen in blue. In fact, the scheme of mapping these narrow atomic emission lines (SHO) into the broader colors (RGB) is adopted in many Hubble images of emission nebulae. This image spans about 50 light-years across the center of the Rosette Nebula. The nebula lies some 3,000 light-years away in the constellation Monoceros.

Globular Star Cluster 47 Tuc

08/02/2024

Globular star cluster 47 Tucanae is a jewel of the southern sky. Also known as NGC 104, it roams the halo of our Milky Way Galaxy along with some 200 other globular star clusters. The second brightest globular cluster (after Omega Centauri) as seen from planet Earth, 47 Tuc lies about 13,000 light-years away. It can be spotted with the naked-eye close on the sky to the Small Magellanic Cloud in the constellation of the Toucan. The dense cluster is made up of hundreds of thousands of stars in a volume only about 120 light-years across. Red giant stars on the outskirts of the cluster are easy to pick out as yellowish stars in this sharp telescopic portrait. Tightly packed globular cluster 47 Tuc is also home to a star with the closest known orbit around a black hole.

Η Αστρονομική Εικόνα της Ημέρας από τη NASA

Spiral Galaxy NGC 6744

01/11/2024