Unusual Aurora During Solar Wind Dropout
23.12.1999

On May 10, for some unknown reason, the Solar Wind virtually stopped. Normally our Sun emits a wind of between five and ten energetic particles per cubic centimeter moving outward at about 500 kilometers per second.

Spiraling Supermassive Black Holes
3.12.2018

Do black holes glow when they collide? When merging, co-orbiting black holes are sure to emit a burst of unusual gravitational radiation, but will they emit light, well before that, if they are surrounded by gas? To help find out, astrophysicists created a sophisticated computer simulation.

APOD: 2023 May 3 Б Centaurus A: A Peculiar Island of Stars
3.05.2023

Galaxies are fascinating. In galaxies, gravity alone holds together massive collections of stars, dust, interstellar gas, stellar remnants and dark matter. Pictured is NGC 5128, better known as Centaurus A. Cen A is the fifth brightest galaxy on the sky and is located at a distance of about 12 million light years from Earth.

C153 Takes the Plunge
6.09.2004

A comet-like tail of glowing gas, 200,000 light-years long, streams from galaxy C153 as it plunges through galaxy cluster Abell 2125 at nearly 8 million kilometers per hour. Itself a member of the giant cluster of galaxies, C153 may once have been a spiral galaxy like the Milky Way.

APOD: 2025 December 2 Б M77: Spiral Galaxy with an Active Center
2.12.2025

What's happening in the center of nearby spiral galaxy M77? The face-on galaxy lies a mere 47 million light-years away toward the constellation of the Sea Monster (Cetus). At that estimated distance, this gorgeous island universe is about 100 thousand light-years across.

M106 in Canes Venatici
30.07.2005

Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial nebula was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106.

M106: A Spiral Galaxy with a Strange Core
15.02.2000

What's happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106's appearance is dominated by two bright spiral arms and dark dust lanes near the nucleus. Bright newly formed stars near their outer tips distinguish the spiral arms in the above photograph.

Vela Supernova Remnant in Visible Light
13.02.2007

The explosion is over but the consequences continue. About eleven thousand years ago a star in the constellation of Vela could be seen to explode, creating a strange point of light briefly visible to humans living near the beginning of recorded history.

Black Hole Signature From Advective Disks
15.01.1997

What does a black hole look like? If alone, a black hole would indeed appear quite black, but many black hole candidates are part of binary star systems. So how does a black hole binary system look different from a neutron star binary system? The above drawings indicate it is difficult to tell!

M27: The Dumbbell Nebula
12.07.2021

What will become of our Sun? The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets.