A Twisted Solar Eruptive Prominence
24.01.2015

Ten Earths could easily fit in the "claw" of this seemingly solar monster. The monster, actually a huge eruptive prominence, is seen moving out from our Sun in this condensed half-hour time-lapse sequence. This large prominence, though, is significant not only for its size, but its shape.

Comet Meets Moon and Morning Star
12.12.2015

A crescent Moon and brilliant Venus met in predawn skies on December 7, a beautiful conjunction of planet Earth's two brightest celestial beacons after the Sun. Harder to see but also on the scene was Comet Catalina (C/2013 US10).

APOD: 2024 March 3 Б A Total Solar Eclipse Close Up in Real Time
3.03.2024

How would you feel if the Sun disappeared? Many eclipse watchers across the USA surprised themselves in 2017 with the awe that they felt and the exclamations that they made as the Sun momentarily disappeared behind the Moon.

A Backward Sunspot and the New Solar Cycle
30.08.2006

Why is sunspot 905 backwards? Perhaps it is a key marker for the beginning of a new magnetic cycle on our Sun. Every 11 years, our Sun goes through a magnetic cycle, at the end of which its overall magnetic orientation is reversed.

Southwest Mercury
16.02.2003

The planet Mercury resembles a moon. Mercury's old surface is heavily cratered like many moons. Mercury is larger than most moons but smaller than Jupiter's moon Ganymede and Saturn's moon Titan. Mercury is much denser and more massive than any moon, though, because it is made mostly of iron.

Jet Approaching a Crescent Moon
5.06.2007

No natural clouds appear in this picture. On the left, an airplane cruises through the atmosphere leaving a contrail in its wake. The contrail would normally appear white, but the large volume of air toward the setting Sun preferentially knocks away blue light, giving the reflected trail a bright orange hue.

A Solar Eclipse with a Beaded Ring of Fire
1.03.2017

What kind of eclipse is this? On Sunday, visible in parts of Earth's southern hemisphere, the Moon blocked part of the Sun during a partial solar eclipse. In some locations, though, the effect was a rare type of partial eclipse called an annular eclipse.

Blue Comet Meets Blue Stars
12.02.2018

What's that heading for the Pleiades star cluster? It appears to be Comet C/2016 R2 (PanSTARRS), but here, appearances are deceiving. On the right and far in the background, the famous Pleiades star cluster is dominated by blue light from massive young stars.

The Ghostly Tail of Comet SWAN
6.11.2006

What causes the structure in Comet SWAN's tail? Comet SWAN, which unexpectedly flared up to naked-eye brightness last week, has been showing detail in its ion tail that might be described as ghostly.

Kepler s House in Linz
15.05.2018

Four hundred years ago today (May 15, 1618) Johannes Kepler discovered the simple mathematical rule governing the orbits of the solar system's planets, now recognized as Kepler's Third Law of planetary motion.