The North America nebula on the sky can do what the North America continent on Earth cannot -- form stars. Specifically, in analogy to the Earth-confined continent, the bright part that appears as the

What's that in the sky? Above the city, above most clouds, far in the distance: it's a comet. Pictured, the impressive tail of Comet C/2024 G3 (ATLAS) was imaged from Brasília, Brazil four days ago. Last

What happens after a star explodes? A huge fireball of hot gas shoots out in all directions. When this gas slams into the existing interstellar medium, it heats up so much it glows. Two different supernova

It was a new year, and the sky was doubly red. The new year meant that the Earth had returned to its usual place in its orbit on January 1, a place a few days before its closest approach to the Sun. The

Billions of years from now, only one of these two galaxies will remain. Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas,

clipses tend to come in pairs. Twice a year, during an eclipse season that lasts about 34 days, Sun, Moon, and Earth can nearly align. Then the full and new phases of the Moon, separated by just over 14

Recorded during 2024, this year-spanning series of images reveals a pattern in the seasonal drift of the Sun's daily motion through planet Earth's sky. Known to some as an analemma, the figure-eight curve

The closest star system to the Sun is the Alpha Centauri system. Of the three stars in the system, the dimmest -- called Proxima Centauri -- is actually the nearest star. The bright stars Alpha Centauri

Is this what will become of our Sun? Quite possibly. The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to

What are these bubbles frozen into Lake Baikal? Methane. Lake Baikal, a UNESCO World Heritage Site in Russia, is the world's largest (by volume), oldest, and deepest lake, containing over 20% of the world's

Orion seems to come up sideways, climbing over a distant mountain range in this deep skyscape. The wintry scene was captured from southern Poland on the northern hemisphere's long solstice night. Otherwise

No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual

Viewed face-on, grand spiral galaxy NGC 5643 has a festive appearance in this colorful cosmic portrait. Some 55 million light-years distant, the galaxy extends for over 100,000 light-years, seen within

Why is there a huge eye in the sky? Diamond dust. That is an informal term for small ice crystals that form in the air and flitter to the ground. Because these crystals are geometrically shaped, they can

The Tarantula Nebula, also known as 30 Doradus, is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud. About 180 thousand

For northern hemisphere dwellers, September's Full Moon was the Harvest Moon. Reflecting warm hues at sunset it rises over the historic town of Castiglione di Sicilia in this telephoto view from September

It is one of the largest nebulas on the sky -- why isn't it better known? Roughly the same angular size as the Andromeda Galaxy, the Great Lacerta Nebula can be found toward the constellation of the Lizard

rlier this month, the Sun exhibited one of the longer filaments on record. Visible as the bright curving streak around the image center, the snaking filament's full extent was estimated to be over half

What are those red filaments in the sky? They are a rarely seen form of lightning confirmed only about 35 years ago: red sprites. Research has shown that following a powerful positive cloud-to-ground lightning

This 180 degree panoramic night skyscape captures our Milky Way Galaxy as it arcs above the horizon on a winter's night in August. Near midnight, the galactic center is close to the zenith with the clear