NGC 6791: An Old, Large Open Cluster
NGC 6791 is one of the oldest and largest open clusters of stars known. But how did it get so dirty? Open star clusters usually contain a few hundred stars each less than a billion years old. Open star cluster NGC 6791, however, contains ...
The Rosette Nebula in Hydrogen,...
The Rosette Nebula is a large emission nebula located 3000 light-years away. The great abundance of hydrogen gas gives NGC 2237 its red color in most photographs. The wind from the open cluster of stars known as NGC 2244
Brown Sun Bubbling
Our Sun may look like all soft and fluffy, but its not. Our Sun is an extremely large ball of bubbling hot gas, mostly hydrogen gas. The above picture was taken in a specific color of light emitted by hydrogen gas called Hydrogen-alpha. ...
Galaxy Dwingeloo 1 Emerges
Sometimes you can't see the forest for the trees. But if you look closely at the center of the above photograph, you will see a whole spiral galaxy behind the field of stars. Named Dwingeloo 1, this nearby galaxy was only discovered recently ...
NGC 4214: Star Forming Galaxy
Dazzling displays of star formation abound across the face of galaxy NGC 4214, a mere 13 million light-years away in the northern constellation Canes Venatici. While this 1997 Hubble Space Telescope image shows the numerous faint, older stars of ...
Galaxies Cluster Toward the Great...
Galaxies dot the sky like jewels in the direction of a mass so large it is known simply as the Great Attractor. The galaxies pictured above are part of a cluster of galaxies called ACO 3627 near the center of the Great Attractor. Previously, ...
Cas A Supernova Remnant in X-Rays
The complex shell of a star seen to explode 300 years ago is helping astronomers to understand how that star exploded. The above recently released image of supernova remnant Cassiopeia A (Cas A) shows unprecedented detail in three X-ray colors. ...
The Largest Rock Known
There, that faint dot in the center - that's the largest rock known. It is larger than every known asteroid, moon, and comet nucleus. It is larger than any other rocky planet. (Nobody knows for sure what size rocks lie at the cores of Jovian ...
The Millennium that Defines Universe
Welcome to the millennial year at the threshold of millennium three. During millennium two, humanity continually redefined its concept of "Universe": first as spheres centered on the Earth, in mid-millennium as the Solar System, a few centuries ...
The Millennium that Defined Earth
When the second millennium began, people generally knew that the Earth was round, but few saw much of it beyond their local village. As the millennium progressed, humans mapped the continents, circumnavigated the globe, and determined the ...
