The Butterfly Planetary Nebula
21.10.1997

As stars age, they throw off their outer layers. Sometimes a highly symmetric gaseous planetary nebula is created, as is the case in M2-9, also called the Butterfly. Most planetary nebulae show this bipolar appearance, although some appear nearly spherical.

Mammatus Clouds over Nebraska
15.12.2019

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms.

Bubbles and Arcs in NGC 2359
2.01.1997

What caused the bubbles and arcs in NGC 2359? The main suspect is the Wolf-Rayet star in the center of one of the bubbles - visible slightly below and to the right of the center of the above photograph.

Spiral Galaxy M83
19.04.1997

The long winding arms of this nearby spiral galaxy define it as the "Southern Pinwheel." But M83 is quite a typical spiral - much like our own Milky Way Galaxy. Spiral galaxies contains many billions of stars, the youngest of which inhabit the spiral arms and glow strongly in blue light.

Closeup of Antennae Galaxy Collision
27.10.1997

It's a clash of the titans. Two galaxies are squaring off in Corvus and here are the latest pictures. When two galaxies collide, however, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small amount of that space.

Clouds Near the Edge of Space
22.08.2012

Noctilucent or night-shining clouds lie near the edge of space. From about 80 kilometers above Earth's surface, the icy clouds can still reflect sunlight even though the Sun itself is below the horizon as seen from the ground.

Mammatus Clouds over Nebraska
15.04.2014

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms.

Mammatus Clouds Over Saskatchewan
18.10.2015

Why is this cloud so bubbly? Normally, cloud bottoms are flat. The flatness is caused by moist warm air that rises and cools and so condenses into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms.

Creature Aurora Over Norway
18.11.2018

It was Halloween and the sky looked like a creature. Exactly which creature, the astrophotographer was unsure but (possibly you can suggest one). Exactly what caused this eerie apparition in 2013 was sure: one of the best auroral displays in recent years. This spectacular aurora had an unusually high degree of detail.

Crescent Neptune and Triton
25.07.2021

Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase. The elegant picture of the gas giant planet and its cloudy moon was taken from behind just after closest approach in 1989.