Anticrepuscular Rays Over Horseshoe Canyon
26.02.2003

What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds.

Genesis Missions Hard Impact
14.09.2004

A flying saucer from outer space crash-landed in the Utah desert last week after being tracked by radar and chased by helicopters. No space aliens were involved, however. The saucer, pictured above...

Aurora Through a Moonlit Sky
2.11.1999

A night sky can glow in fascinating ways. Through a clearing in the woods, the pictured sky above Alaska shines by reflected light from a nearby city, by the brightness of the Moon, and by aurora.

Light Pillars over Alaska
8.02.2016

What's happening behind those houses? Pictured here are not auroras but nearby light pillars, a nearby phenomenon that can appear as a distant one. In most places on Earth, a lucky viewer...

Comet LINEAR Breaks Up
31.07.2000

Unexpectedly, Comet LINEAR is breaking up. In retrospect, clues of its demise have been surfacing all month as the new comet has been approaching the Sun and brightening with dramatic flares. Above, the Hubble Space Telescope captured Comet C/1999 S4 LINEAR early this month blowing off a large piece of its crust.

A Twisted Solar Eruptive Prominence
1.06.2008

Ten Earths could easily fit in the "claw" of this seemingly solar monster. The monster, though, visible on the lower left, is a huge eruptive prominence seen moving out from our Sun. The above dramatic image taken early in the year 2000 by the Sun-orbiting SOHO satellite.

A Solar Prominence from SOHO
31.05.2009

How can gas float above the Sun? Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the solar limb.

Goldilocks Zones and Stars
31.01.2020

The Goldilocks zone is the habitable zone around a star where it's not too hot and not too cold for liquid water to exist on the surface of orbiting planets. This intriguing infographic...

APOD: 2023 December 3 Б Moon Setting Behind Teide Volcano
3.12.2023

These people are not in danger. What is coming down from the left is just the Moon, far in the distance. Luna appears so large here because she is being photographed through a telescopic lens.

APOD: 2026 May 11 Б Moon Setting Behind Teide Volcano
11.05.2026

These people are not in danger. What is coming down from the left is just the Moon, far in the distance. Luna appears so large here because she is being photographed through a telescopic lens.