Zodiacal Light Over Namibia
13.09.2010

An unusual triangle of light is visible this time of year just before dawn, in the northern hemisphere. Once considered a false dawn, this triangle of light is actually zodiacal light, light reflected from interplanetary dust particles.

J102815: A Star That Should Not Exist
7.09.2011

Why does this star have so few heavy elements? Stars born in the generation of our Sun have an expected abundance of elements heavier than hydrogen and helium mixed into their atmospheres. Stars born...

APOD: 2023 February 22 Б Our Increasingly Active Sun
22.02.2023

Our Sun is becoming a busy place. Only two years ago, the Sun was emerging from a solar minimum so quiet that months would go by without even a single sunspot. In contrast, already...

Elliptical Galaxy NGC 1132
13.02.2008

NGC 1132 is one smooth galaxy -- but how did it form? As an elliptical galaxy, NGC 1132 has little dust and gas, and few stars have formed in it recently. Although many elliptical galaxies are in clusters of galaxies, NGC 1132 appears as a large, isolated galaxy toward the constellation of the River (Eridanus).

Thirty Thousand Kilometers Above Enceladus
17.03.2008

What does the surface of Saturn's ice-spewing moon Enceladus look like? To help find out, the robotic Cassini spacecraft now orbiting Saturn was sent soaring past the cryovolcanic moon and even right through one of Enceladus' ice plumes. Cassini closed to about 52 kilometers during its closest encounter to date.

Hoags Object: A Strange Ring Galaxy
22.08.2010

Is this one galaxy or two? This question came to light in 1950 when astronomer Art Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older.

Rainbow Airglow over the Azores
22.03.2016

Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.

APOD: 2025 April 27 Б IC 418: The Spirograph Nebula
27.04.2025

What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows patterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours.

The Milky Way Over Ontario
29.07.2008

Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month over Ontario, Canada, when part of a spectacular sky also became visible in a reflection off a lake.

Rosetta Spacecraft Passes Asteroid Steins
8.09.2008

What's that diamond in the sky? Cruising though space, sometimes you'll come across an unusual object. Such was the case on Friday for ESA's Rosetta spacecraft on it's way to comet Churyumov-Gerasimenko in 2014.