Aurora Over Winnipeg
5.11.2001

What's happening above that city? The city is Winnipeg, Canada, and the phenomenon is aurora. These past few months have been active ones for our Sun, producing several coronal mass ejections (CMEs) of particles that have swept past our Earth and caused many spectacular auroras.

An Energetic Radio Galaxy
30.09.1995

The radio and optical emission seen in the above superposed images of the radio galaxy 3C368 indicate that energetic processes are at work. A radio galaxy is a galaxy that is visible to radio telescopes. A large radio signal usually indicates very powerful phenomena.

Star Cluster Messier 67
9.08.2007

Gathered at the center of this sharp skyview are the stars of Messier 67, one of the oldest known open star clusters. In fact, though open star clusters are usually much younger, the stars...

Haunting the Cepheus Flare
28.10.2016

Spooky shapes seem to haunt this jeweled expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds faintly visible in dimly reflected starlight. Far from your...

APOD: 2025 January 22 Б The North America Nebula
22.01.2025

The North America nebula on the sky can do what the North America continent on Earth cannot -- form stars. Specifically, in analogy to the Earth-confined continent, the bright part that appears as the east coast is actually a hot bed of gas, dust, and newly formed stars known as the Cygnus Wall.

Shell Game in NGC 300
22.08.2002

Featured in color in yesterday's episode, big, beautiful, face-on spiral galaxy NGC 300 is seen here through a narrow filter that transmits only the red light of hydrogen atoms. Ionized by energetic starlight, a hydrogen atom emits the characteristic red H-alpha light as its single electron is recaptured and transitions to lower energy states.

Hoags Object: A Strange Ring Galaxy
9.09.2002

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.

Arp 188 and the Tadpole s Tidal Tail
15.05.2004

In this stunning vista recorded with the Hubble Space Telescope's Advanced Camera for Surveys, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco.

Simeis 147: Supernova Remnant from Palomar
29.11.2005

It's easy to get lost following the intricate filaments in this detailed image of faint supernova remnant Simeis 147. Seen towards the constellation Taurus it covers nearly 3 degrees (6 full moons) on the sky corresponding to a width of 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years.

Young Star Cluster Westerlund 2
31.01.2008

Dusty stellar nursery RCW 49 surrounds young star cluster Westerlund 2 in this remarkable composite skyscape from beyond the visible spectrum of light. Infrared data from the Spitzer Space Telescope is shown in black...