Comet NEOWISE over the Swiss Alps
14.07.2020

Comet NEOWISE has been wowing photographers around much of the world during dawn and dusk, at the margins of day and night. For the most northern residents of planet Earth, however, the comet circles the North Star and never sets.

APOD: 2025 December 1 Б 3I ATLAS: Tails of an Interstellar Comet
30.11.2025

How typical is our Solar System? Studying 3I/ATLAS, a comet just passing through, is providing clues. Confirmed previous interstellar visitors include an asteroid, a comet, a meteor, and a gas wind dominated by hydrogen and helium.

Galactic Center Flicker Indicates Black Hole
10.09.2001

Why would the center of our Galaxy flicker? Many astronomers believe the only credible answer involves a black hole. During observations of Sagittarius A* with the orbiting Chandra X-ray Observatory, the bright X-ray source at the very center of our Milky Way brightened dramatically for a few minutes.

Three Month Composite of Comet Holmes
4.02.2008

How has Comet Holmes changed? Since brightening unexpectedly by nearly one million fold in late October, the last three months have found the coma of Comet 17P/Holmes both expanding and fading. This spectacular composite image shows how the coma and tail of Comet Holmes have changed.

Dust and the NGC 7771 Group
20.01.2010

Galaxies of the NGC 7771 Group are featured in this intriguing skyscape. Some 200 million light-years distant toward the constellation Pegasus, NGC 7771 is the large, edge-on spiral near center, about 75,000 light-years across, with two smaller galaxies just below it. Large spiral NGC 7769 is seen face-on to the right.

Halloween and the Ghost Head Nebula
31.10.2010

Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere). With a modern calendar, however, the real cross-quarter day will occur next week.

Aurora Over White Dome Geyser
17.10.2012

Sometimes both heaven and Earth erupt. Colorful aurorae erupted unexpectedly earlier this month, with green aurora appearing near the horizon and brilliant bands of red aurora blooming high overhead. A bright Moon lit the foreground of this picturesque scene, while familiar stars could be seen far in the distance.

A Phoenix Aurora over Iceland
15.03.2016

All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet night last September, much of that night's auroras had died down. Suddenly though, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again.

Full Venus and Crescent Moon Rise
13.04.2016

Inner planet Venus and a thin crescent Moon are never found far from the Sun in planet Earth's skies. Taken near dawn on April 6, this timelapse composite shows them both rising just before the Sun. The mountaintop Teide Observatory domes on the fortunate island of Tenerife appear in silhouette against the twilight.

Markarian s Chain to Messier 64
23.06.2017

Top to bottom, this colorful and broad telescopic mosaic links Markarian's Chain of galaxies across the core of the Virgo Cluster to dusty spiral galaxy Messier 64. Galaxies are scattered through the field of view that spans some 20 full moons across a gorgeous night sky.