A Sky Full Of Hydrogen
1.03.1998

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.

Our Galaxy in Stars, Gas, and Dust
28.09.2003

The disk of our Milky Way Galaxy is home to hot nebulae, cold dust, and billions of stars. The red nebulae visible in the above contrast-enhanced picture are primarily emission nebulae, glowing clouds of hydrogen gas heated by nearby, bright, young stars.

Stars Without Galaxies
27.03.1999

Galaxies are made up of stars, but are all stars found within galaxies? Using the Hubble Space Telescope, researchers exploring the Virgo Cluster of galaxies have now found about 600 red giant stars adrift in intergalactic space. Above is an artist's vision of the sky from a hypothetical planet of such a lonely sun.

Barnard Stares at NGC 2170
19.01.2013

A gaze across a cosmic skyscape, this telescopic mosaic reveals the continuous beauty of things that are. The evocative scene spans some 6 degrees or 12 Full Moons in planet Earth's sky. At the left, folds of red, glowing gas are a small part of an immense, 300 light-year wide arc.

Cygnus: Bubble and Crescent
4.12.2015

These clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. Caught within the telescopic field of view are the Soap Bubble (lower left) and the Crescent Nebula (upper right).

Veil Nebula: Wisps of an Exploded Star
19.09.2017

Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history.

The Star Streams of NGC 5907
16.11.2019

Grand tidal streams of stars seem to surround galaxy NGC 5907. The arcing structures form tenuous loops extending more than 150,000 light-years from the narrow, edge-on spiral, also known as the Splinter or Knife Edge Galaxy.

Comet C 2017 K2 (PanSTARRS)
30.06.2022

Imaged on June 20 2022, comet C/2017 K2 (PanSTARRS) shares this wide telescopic field of view with open star cluster IC 4665 and bright star Beta Ophiuchi, near a starry edge of the Milky Way.

Galactic Center Flicker Indicates Black Hole
10.09.2001

Why would the center of our Galaxy flicker? Many astronomers believe the only credible answer involves a black hole. During observations of Sagittarius A* with the orbiting Chandra X-ray Observatory, the bright X-ray source at the very center of our Milky Way brightened dramatically for a few minutes.

The Local Bubble and the Galactic Neighborhood
17.02.2002

What surrounds the Sun in this neck of the Milky Way Galaxy? Our current best guess is depicted in the above map of the surrounding 1500 light years constructed from various observations and deductions.