Αστρονομική Εικόνα της Ημέρας από τη NASA

Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA

Fireball over Iceland

16/09/2023

On September 12, from a location just south of the Arctic Circle, stones of Iceland's modern Arctic Henge point skyward in this startling scene. Entertaining an intrepid group of aurora hunters during a geomagnetic storm, alluring northern lights dance across the darkened sky when a stunning fireball meteor explodes. Awestruck, the camera-equipped skygazers captured video and still images of the boreal bolide, at its peak about as bright as a full moon. Though quickly fading from view, the fireball left a lingering visible trail or persistent train. The wraith-like trail was seen for minutes wafting in the upper atmosphere at altitudes of 60 to 90 kilometers along with the auroral glow.

Venus, Moon, and the Smoking Mountain

15/09/2023

Venus has returned, now appearing in planet Earth's predawn skies as a brilliant morning star. From a window seat on a flight to Mexico City, the bright celestial beacon was captured just before sunrise in this astronomical snapshot, taken on September 12. Venus, at the upper right, shared the early twilight with an old crescent Moon. Seen from this stratospheric perspective, mountain peaks and clouds appear in silhouette along a glowing eastern horizon. The dramatic, long, low cloud bank was created by ongoing venting from planet Earth's active volcano Popocatépetl.

NGC 7331 and Beyond

14/09/2023

Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, long telescopic exposures often result in images that evokes a strong sense of depth. The effect is further enhanced in this sharp image by galaxies that lie beyond the gorgeous island universe. The most prominent background galaxies are about one tenth the apparent size of NGC 7331 and so lie roughly ten times farther away. Their close alignment on the sky with NGC 7331 occurs just by chance. Lingering above the plane of the Milky Way, this striking visual grouping of galaxies is known to some as the Deer Lick Group.

NGC 4632: Galaxy with a Hidden Polar Ring

13/09/2023

Galaxy NGC 4632 hides a secret from optical telescopes. It is surrounded by a ring of cool hydrogen gas orbiting at 90 degrees to its spiral disk. Such polar ring galaxies have previously been discovered using starlight. However, NGC 4632 is among the first in which a radio telescope survey revealed a polar ring. The featured composite image combines this gas ring, observed with the highly sensitive ASKAP telescope, with optical data from the Subaru telescope. Using virtual reality, astronomers separated out the gas in the main disk of the galaxy from the ring, and the subtle color gradient traces its orbital motion. Why do polar rings exist? They could be material pulled from one galaxy as it gravitationally interacts with a companion. Or hydrogen gas flows along the filaments of the cosmic web and accretes into a ring around a galaxy, some of which gravitationally contracts into stars.

Galaxy Cluster Abell 370 and Beyond

12/09/2023

Some 4 billion light-years away, massive galaxy cluster Abell 370 is captured in this sharp Hubble Space Telescope snapshot. The cluster of galaxies only appears to be dominated by two giant elliptical galaxies and infested with faint arcs. In reality, the fainter, scattered bluish arcs, along with the dramatic dragon arc below and left of center, are images of galaxies that lie far beyond Abell 370. About twice as distant, their otherwise undetected light is magnified and distorted by the cluster's enormous gravitational mass, overwhelmingly dominated by unseen dark matter. Providing a tantalizing glimpse of galaxies in the early universe, the effect is known as gravitational lensing. A consequence of warped spacetime, lensing was predicted by Einstein almost a century ago. Far beyond the spiky foreground Milky Way star at lower right, Abell 370 is seen toward the constellation Cetus, the Sea Monster. It was the last of six galaxy clusters imaged in the Frontier Fields project.

Beautiful Comet Nishimura

11/09/2023

This scene would be beautiful even without the comet. By itself, the sunrise sky is an elegant deep blue on high, with faint white stars peeking through, while near the horizon is a pleasing tan. By itself, the foreground hills of eastern Slovakia are appealingly green, with the Zadňa hura and Veľká hora hills in the distance, and with the lights of small towns along the way. Venus, by itself on the right, appears unusually exquisite, surrounded by a colorful atmospheric corona. But what attracts the eye most is the comet. On the left, in this composite image taken just before dawn yesterday morning, is Comet Nishimura. On recent mornings around the globe, its bright coma and long ion tail make many a morning panoramic photo unusually beautiful. Tomorrow, C/2023 P1 (Nishimura) will pass its nearest to the Earth for about the next 434 years.

An Annular Solar Eclipse over New Mexico

10/09/2023

What is this person doing? In 2012, an annular eclipse of the Sun was visible over a narrow path that crossed the northern Pacific Ocean and several western US states. In an annular solar eclipse, the Moon is too far from the Earth to block out the entire Sun, leaving the Sun peeking out over the Moon's disk in a ring of fire. To capture this unusual solar event, an industrious photographer drove from Arizona to New Mexico to find just the right vista. After setting up and just as the eclipsed Sun was setting over a ridge about 0.5 kilometers away, a person unknowingly walked right into the shot. Although grateful for the unexpected human element, the photographer never learned the identity of the silhouetted interloper. It appears likely that the person is holding a circular device that would enable them to get their own view of the eclipse. The shot was taken at sunset on 2012 May 20 at 7:36 pm local time from a park near Albuquerque. Next month, on October 14, a different narrow swath across North and South America will be exposed to a different annular solar eclipse, if the sky is clear. Simultaneously, cloud-free observers almost anywhere on either continent will be able to see a partial solar eclipse.

Comet Nishimura Grows

09/09/2023

Comet Nishimura is growing. More precisely, the tails C/2023 P1 (Nishimura) are growing as it nears the Sun. Discovered only last month, the comet is already near naked eye brightness as it now moves inside the Earth's orbit. The comet will be nearest the Earth next week, but nearest the Sun the week after -- on September 17. Speculation holds that expelled ice and dust from Comet Nishimura's last visit to the inner Solar System may have created the Sigma Hydrids meteor shower which peaks yearly in December. If so, then this meteor shower may become more active, refreshed with new comet debris. Pictured, Comet Nishimura was captured from Edgewood, New Mexico, USA four nights ago, showing a long ion tail structured by interactions with the Sun's wind. Look for this comet near your eastern horizon just before sunrise for the next few mornings, but very near your western horizon just after sunset next week -- as its coma continues to brighten and its tails continue to grow. Gallery: Selected Comet Nishimura images submitted to APOD

Η Αστρονομική Εικόνα της Ημέρας από τη NASA

3I/ATLAS Flyby

26/12/2025