Clouds of Earth and Sky
24.07.2018

If you go high enough, you may find yourself on a picturesque perch between the water clouds of the Earth and the star clouds of the Milky Way. Such was the case last month for one adventurous alpinist astrophotographer.

Iridescent Clouds over Thamserku
8.07.2014

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size.

A Retreating Thunderstorm at Sunset
16.01.2022

What type of cloud is that? This retreating cumulonimbus cloud, more commonly called a thundercloud, is somewhat unusual as it contains the unusual bumpiness of a mammatus cloud on the near end, while simultaneously producing falling rain on the far end.

Mysterious Acid Haze on Venus
26.02.2008

Why did an acidic haze spread across Venus? The unusual clouds were discovered last July by ESA's robotic Venus Express spacecraft currently orbiting Venus. The bright and smooth haze was found by Venus...

An Iridescent Cloud Over France
13.04.2004

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size.

Space Shuttle Rising
25.05.2011

What's that rising from the clouds? The space shuttle. If you looked out the window of an airplane at just the right place and time last week, you could have seen something very unusual -- the space shuttle Endeavour launching to orbit.

APOD: 2026 August 2 Б A Fire Rainbow over West Virginia
2.08.2026

What's happening to this cloud? Ice crystals in a distant cirrus cloud are acting like little floating prisms. Known informally as a fire rainbow for its flame-like appearance, a circumhorizon arc appears parallel to the horizon.

Meteors Between Stars and Clouds
11.12.2002

Streaking high above diffuse clouds -- but well in front of distant stars -- are sand-sized bits of an ancient comet: meteors. These bits flaked off Comet Tempel-Tuttle during its pass through the inner Solar System about 150 years ago. Far in the background are stars toward the constellation of Ursa Major.

APOD: 2025 August 17 Б Asperitas Clouds Over New Zealand
17.08.2025

What kind of clouds are these? Although their cause is presently unknown, such unusual atmospheric structures, as menacing as they might seem, do not appear to be harbingers of meteorological doom. Formally recognized as a distinct cloud type only last year, asperitas clouds can be stunning in appearance, unusual in occurrence, and are relatively unstudied.

Mammatus Clouds over Mount Rushmore
7.12.2020

What's that below those strange clouds? Presidents. If you look closely, you may recognize the heads of four former US Presidents carved into famous Mount Rushmore in South Dakota, USA. More obvious in the featured image are the unusual mammatus clouds that passed briefly overhead.