Αστρονομική Εικόνα της Ημέρας από τη NASA

Προηγούμενες Αστρονομικές Εικόνες της Ημέρας από τη NASA

Black Holes and Neutron Stars: 218 Mergers and Counting

26/03/2026

What is the sound of two black holes merging in deep space? Sound waves don't propagate in vacuum, but gravitational waves do. In 2015 we were able to "hear" them for the first time and confirm one of Albert Einstein's theoretical predictions. Each square on the grid of the featured image represents one of the gravitational wave detections announced so far by the LIGO-VIRGO-KAGRA Collaboration. These plots show how the binary pair accelerates in their orbit around each other towards merger: the rising frequency effect is called a "chirp". Although there are significantly more neutron stars than black holes, most of the detections are binary black hole mergers. That happens because black holes are heavier and their signals are louder and can be seen farther away, resulting in more detections. These events are rare, and we don't expect to see one close by in our Galaxy any time soon. But they are happening continuously throughout the cosmos.

The Guardians of Rapa Nui beneath the Milky Way

25/03/2026

In the words of today's astrophotographer, Rositsa Dimitrova, "What have these silent sentinels watched pass across the sky?" The volcanic mo'ai (meaning statue) of Ahu Tongariki stand guard over Rapa Nui (Isla de Pascua, Easter Island), a Polynesian island (annexed by Chile in 1888) located thousands of kilometers off the coast of South America in the Pacific Ocean. Due to the island's remoteness, the mo'ai, with their backs to the dark ocean, are able to gaze upon a clear and vibrant night sky. Pictured, these larger-than-life statues stare at the bright band of the Milky Way, partly obscured by interstellar dust and blurred by Earth's clouds. Under such clear night skies, the Rapa Nui created observatories and used astronomical observations for navigation, calendar calibration, celebrations, and more. Images like this one remind us of the importance of dark skies, protecting the land underneath them, and preserving the culture that they inspire.

Light Pillars and Orion over Mohe

23/03/2026

What's happening at the end of that street? Pictured here are not auroras but light pillars, a phenomenon typically much closer. In most places on Earth, a lucky viewer can see a Sun pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere. Usually, these ice crystals evaporate before reaching the ground. During freezing temperatures, however, flat fluttering ice crystals may form near the ground and are sometimes known as a crystal fog. These small ice crystals may then reflect not the Sun but ground lights. The featured image captured not only numerous light pillars but also the iconic constellation of Orion, and was taken in Mohe, the northernmost city in China.

Galaxies in the River: NGC 1300 and NGC 1297

21/03/2026

Spiral NGC 1300 and elliptical NGC 1297 are galaxies that lie on the banks of the southern constellation Eridanus (The River). At 70 million light-years distant or more, both are members of the Eridanus Galaxy Cluster. About 100,000 light-years across, at lower left in this sharp, galaxy group photo NGC 1300 is seen face-on with a prominent central bar and grand, sweeping spiral arms. Like other spiral galaxies, including our own barred spiral Milky Way Galaxy, NGC 1300 is thought to have a supermassive central black hole. A contrast in appearance and slightly more distant, NGC 1297 is the roughly spherical large elliptical galaxy near the top of the frame. With little active star formation, elliptical galaxies are composed of older populations of stars and are likely he result of multiple collisions and mergers with spirals.

Spring Equinox at Teide Observatory

20/03/2026

The defining astronomical moment of the equinox today is at 14:46 UTC (March 20). That's when the Sun crosses the celestial equator moving north in its yearly journey through planet Earth's sky, marking the beginning of spring for our fair planet in the northern hemisphere and fall in the southern hemisphere. Then, day and night are nearly equal around the globe. In fact, both day and nighttime exposures from a spring equinox at the Observatorio del Teide in Tenerife, Canary Islands, Spain, are used in this composited skyscape. Over 1,000 images were taken with a fisheye lens and merged in the ambitious equinox project. The apparent motion of the Sun setting along the celestial equator on the equinox date follows the bright linear, diagonal track from the sequence of daytime exposures taken over 6 hours. After sunset, nighttime exposures recorded startrails, with the celestial equator as a linear track and concentric arcs circling the north celestial pole near Polaris at upper right and the south celestial pole beyond the lower left edge (and below the Teide horizon). The foreground includes the distant Teide volcano peak and the observatory's pyramid-shaped solar laboratory building.

Launch Plume: SpaceX Jellyfish

19/03/2026

ven if you live with your head in the clouds, you won’t find a jellyfish like this one very often. The featured image shows a SpaceX Falcon 9 rocket launch from Cape Canaveral in Florida on March 4. The launch happened 52 minutes before sunrise, and the second stage rocket exhaust plume was high enough in the sky to catch the light of the rising sun, while the photographer was still in the dark. This combination of light and shadow, possible at dawn or dusk, makes the exhaust, mostly water vapor and carbon dioxide, appear as a glowing cloud. It only looks like it's going down, as the rocket follows the curvature of the Earth on its way to space. A related effect is the twilight phenomenon, which causes colorful contrails sometimes mistaken for UFOs. But, in case you are wondering: real jellyfish were sent to space by NASA in the 1990s as part of a science experiment.

Cygnus and the Solitary Tree

18/03/2026

A lone tree stands in a quiet meadow in Guadalajara, Spain, silhouetted against the Cygnus region rising above like flames in the night sky. This deep night skyscape is a composite of exposures that reveals a range of brightness and color human eyes can't quite see on their own. Spanning over a thousand times the angular size of the full moon, Cygnus sets the sky afire with active star formation where clouds of gas and dust collapse under gravity until nuclear fusion ignites and new stars are born. These stars ionize the surrounding hydrogen gas, causing it to glow crimson, while tendrils of interstellar dust absorb some of that light and cast dark shadows across the sky. Cygnus is a trove of celestial treasures, notably the Veil, Crescent, and Pelican nebulae, as well as Cygnus X-1, the first confirmed black hole. Cygnus continues to yield fresh science, including a new three-dimensional model of the Cygnus Loop made possible by the Chandra X-ray Observatory. Almost Hyperspace: Random APOD Generator

The Tadpoles of IC 410

17/03/2026

This telescopic close-up shows off the central regions of otherwise faint emission nebula IC 410, captured under backyard skies. Presented in a Hubble color palette, the image combines visible broadband and narrowband data with data from the near-infrared. Below and right of center are two remarkable inhabitants of the interstellar pond of gas and dust. the Tadpoles of IC 410. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars. Formed in the interstellar cloud a mere 4 million years ago, the intensely hot, bright cluster stars energize the glowing gas. But the cosmic tadpoles themselves are composed of denser cooler gas and dust. Around 10 light-years long they are likely sites of ongoing star formation. Sculpted by stellar winds and radiation their heads are outlined by bright ridges of ionized gas while their tails trail away from the cluster's central young stars. IC 410 lies some 10,000 light-years away, toward the nebula-rich constellation Auriga.

Η Αστρονομική Εικόνα της Ημέρας από τη NASA

Hickson 44 in Leo

27/03/2026