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.

Lightning over the Volcano of Water
29.07.2019

Have you ever watched a lightning storm in awe? Join the crowd. Details of what causes lightning are still being researched, but it is known that inside some clouds, internal updrafts cause collisions between ice and snow that slowly separate charges between cloud tops and bottoms The rapid electrical discharges that are lightning soon result.

APOD: 2023 May 29 Б Milky Way over a Turquoise Wonderland
29.05.2023

What glows there? The answer depends: sea or sky? In the sea, the unusual blue glow is bioluminescence. Specifically, the glimmer arises from Noctiluca scintillans, single-celled plankton stimulated by the lapping waves. The plankton use their glow to startle and illuminate predators.

APOD: 2025 February 23 Б Saturn in Infrared from Cassini
23.02.2025

Saturn looks slightly different in infrared light. Bands of clouds show great structure, including long stretching storms. Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn's North Pole. Each side of the dark hexagon spans roughly the width of our Earth.

APOD: 2025 August 5 Б NGC 6072: A Complex Planetary Nebula from Webb
5.08.2025

Why is this nebula so complex? The Webb Space Telescope has imaged a nebula in great detail that is thought to have emerged from a Sun-like star. NGC 6072 has been resolved into one of the more unusual and complex examples of planetary nebula.

The Large Cloud of Magellan (LMC)
23.10.1996

Magellan and his crew had plenty of time to study the southern sky during their famous voyage around the world. As a result, two fuzzy cloud like objects in the southern sky are now known as the Clouds of Magellan. These star clouds are small irregular galaxies, satellites of our larger Milky Way spiral galaxy.

A Sonic Boom
4.05.2003

Many people have heard a sonic boom, but few have seen one. When an airplane travels at a speed faster than sound, density waves of sound emitted by the plane cannot precede the plane, and so accumulate in a cone behind the plane.

NGC 4314: A Nuclear Starburst Ring
15.06.1998

Is this old galaxy up to new tricks? The barred spiral galaxy NGC 4314 is billions of years old, but its appearance has changed markedly over just the past few millions of years. During that time, a nuclear ring of bright young stars has been evolving.

A Solar Prominence from SOHO
9.11.2005

What happened to the Sun? Nothing very unusual: the strange-looking solar appendage on the lower left is actually just a spectacular looking version of a common solar prominence. A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field.

The Sombrero Galaxy from HST
15.01.2006

Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge.