Hydrogen in the LMC
26.04.2011

A satellite galaxy of our own Milky Way, the Large Magellanic Cloud (LMC) is an alluring sight in dark southern skies and the constellation Dorado. A mere 180,000 light-years distant...

Galaxy NGC 474: Cosmic Blender
26.07.2011

What's happening to galaxy NGC 474? The multiple layers of emission appear strangely complex and unexpected given the relatively featureless appearance of the elliptical galaxy in less deep images. The cause...

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.

Sharpest Ultima Thule
28.02.2019

On January 1, New Horizons swooped to within 3,500 kilometers of the Kuiper Belt world known as Ultima Thule. That's about 3 times closer than its July 2015 closest approach to Pluto.

The Magnetic Field of the Whirlpool Galaxy
20.01.2021

Do magnetic fields always flow along spiral arms? Our face-on view of the Whirlpool Galaxy (M51) allows a spectacularly clear view of the spiral wave pattern in a disk-shaped galaxy. When observed with a radio telescope, the magnetic field appears to trace the arms' curvature.

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.

X Ray Mystery in RCW 38
27.12.2002

A mere 6,000 light-years distant and sailing through the constellation Vela, star cluster RCW 38 is full of powerful stars. It's no surprise that these stars, only a million years young with hot outer atmospheres, appear as point-like x-ray sources dotting this x-ray image from the orbiting Chandra Observatory.

Fireball Over Edmonton
25.11.2008

What if you're driving down the street and an object from space shoots across the sky right in front of you? Such was the case last week for many people in south central Canada.

Angry Sun Erupting
14.03.2012

It's one of the baddest sunspot regions in years. Active Region 1429 may not only look, to some, like an angry bird -- it has thrown off some of the most powerful flares and coronal mass ejections of the current solar cycle.

A Fox Fur, a Unicorn, and a Christmas Tree
4.01.2015

What do the following things have in common: a cone, the fur of a fox, and a Christmas tree? Answer: they all occur in the constellation of the unicorn (Monoceros). Pictured as a star...