A Sky Full Of Hydrogen
13.01.2001

Interstellar space is filled with extremely tenuous clouds of gas which are mostly Hydrogen. The neutral hydrogen atom (HI in astronomer's shorthand) consists of 1 proton and 1 electron. The proton and electron spin like tops but can have only two orientations; spin axes parallel or anti-parallel.

Stars, Galaxies, and Comet Tempel 1
12.05.2005

Faint comet Tempel 1 sports a fuzzy blue-tinted tail, just right of center in this lovely field of stars. Recorded on May 3rd slowly sweeping through the constellation Virgo, periodic comet Tempel 1 orbits the Sun once every 5.5 years.

The Center of Centaurus A
7.11.2010

A fantastic jumble of young blue star clusters, gigantic glowing gas clouds, and imposing dark dust lanes surrounds the central region of the active galaxy Centaurus A. This mosaic of Hubble Space Telescope images taken in blue, green, and red light has been processed to present a natural color picture of this cosmic maelstrom.

Visual Effects: Wonders of the Universe
18.04.2011

What visual effects are depicted in this video? The effects were created by BDH for the BBC television show Wonders of the Universe, but are unlabeled on the above version posted to Vimeo. Even...

Elliptical M60, Spiral NGC 4647
28.01.2016

Giant elliptical galaxy M60 and spiral galaxy NGC 4647 do look like an odd couple in this sharp cosmic portrait from the Hubble Space Telescope. But they are found in a region of space where galaxies tend to gather, on the eastern side of the nearby Virgo Galaxy Cluster.

Total Lunar Eclipse
10.11.2022

The beginning, middle, and end of a journey through planet Earth's colorful umbral shadow is captured in this timelapse composite image of a total lunar eclipse. Taken on November 8 from Kitt Peak...

X Ray Stars in the Orion Nebula
19.05.2005

When our middle-aged Sun was just a few million years old it was thousands of times brighter in x-rays. In fact, it was likely similar to some of the stars found in this false-color x-ray composite of the Orion Nebula region from the Chandra Observatory.

Blood Moon, Ice Giant
11.11.2022

On November 8 the Full Moon turned blood red as it slid through Earth's shadow in a beautiful total lunar eclipse. During totality it also passed in front of, or occulted, outer planet Uranus for eclipse viewers located in parts of northern America and Asia.

APOD: 2025 August 31 Б NGC 7027: The Pillow Planetary Nebula
31.08.2025

What created this unusual planetary nebula? Dubbed the Pillow Nebula and the Flying Carpet Nebula, NGC 7027 is one of the smallest, brightest, and most unusually shaped planetary nebulas known. Given its expansion rate, NGC 7027 first started expanding, as visible from Earth, about 600 years ago.

The Milky Way Behind an Eclipsed Moon
3.06.2003

What's behind the Moon? Each month, our Moon passes in front of -- and outshines -- many an interesting star field. Exceptions occur during a new Moon and during a total eclipse. In the background...