Tycho's Supernova Remnant in X-ray

1999-03-07

How often do stars explode? By looking at external galaxies, astronomers can guess that these events, known as a supernovae, should occur about once every 30 years in a typical spiral galaxy like our MilkyWay. However, the obscuring gas and dust ...

Miranda, Chevron, and Alonso

1999-03-06

Miranda is a bizarre world which surely had a tempestuous past. The innermost of the larger Uranian moons, Miranda is almost 300 miles in diameter and was discovered in 1948 by American planetary astronomer Gerard Kuiper. Examined very closely by ...

M46 And NGC 2438: Young And Old

1999-03-05 Wil Milan

Galactic or open star clusters are relatively young. These swarms of bright stars are born near the plane of the Milky Way, but their numbers steadily dwindle as cluster members are strewn through the Galaxy by gravitational interactions. This ...

Ganymede Mosaic

1999-03-04

Ganymede, one of the four Galilean moons of Jupiter, is the largest moon in the Solar System. With a diameter of 5,260 kilometers it is even larger than planets Mercury and Pluto and just over three quarters the size of Mars. Ganymede is locked ...

Infrared Mars

1999-03-03

Was Mars wetter and more Earth-like in its distant past? This false-color composite image of Mars is part of the mounting evidence that liquid water once did play a significant role in Martian surface geology. Constructed from infrared imaging ...

The Kleinmann-Low Nebula

1999-03-02

The most active part of the Orion Nebular Cloud Complex is an area known as the Kleinmann-Low Nebula. There, a cluster of young and forming stars is embedded in a molecular cloud filled with dust. In visible light, the dark dust blocks much of ...

Reflection Nebula NGC 1435

1999-03-01 Yuugi Kitahara

Reflection nebulae reflect light from a nearby star. Many small carbon grains in the nebula reflect the light. The blue color typical of reflection nebula is caused by blue light being more efficiently scattered by the carbon dust than red ...

Trapezium: Teardrops in My Skies

1999-02-28

Sometimes the unexpected comes in a familiar shape. In this picture, the seemingly familiar teardrop-shaped object just right of center is actually an unusually situated disk of gas and dust. In fact, the teardrop is about the size of our own ...

Hamlet of Oberon

1999-02-27

What's in a name? Since 1919, the International Astronomical Union has been charged with the task of establishing "conventional" nomenclature for planets, satellites, and surface features. For the remote Uranian system of moons, namesakes from ...

Dark Cloud

1999-02-26

Ominously foreshadowing events to come, a dark cloud of obscuring dust stands out against a luminous star field in the Milky Way. Cataloged as Feitzinger and Stuwe object "1-457" this fuliginous interstellar nebula is relatively close - possibly ...