Deimos: A Small Martian Moon
2.09.2001

Mars has two tiny moons, Phobos and Deimos. Pictured above is Deimos, the smaller moon of Mars. In fact, Deimos is one of the smallest known moons in the Solar System measuring only nine miles across.

Saturn from Earth
2.09.1998

Saturn is the second largest planet in our Solar System. Saturn has been easily visible in the sky since history has been recorded. Galileo used one of the first telescopes in 1610 to discover Saturn's rings, which he first thought were moons.

Trapezium: Teardrops in My Skies
28.02.1999

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 Solar System and is racing against time to condense and form planets.

Comet Hale-Bopp Returns
6.02.1997

Comet Hale-Bopp has returned from behind the Sun. In December and early January, Comet Hale-Bopp was too near the Sun to be easily visible from Earth. Now the comet graces the morning sky and is visible from dark locations even without binoculars.

Arecibo: The Largest Telescope
12.04.1997

The Arecibo radio telescope is currently the largest single-dish telescope in the world. First opening in 1963, this 305 meter (1000 foot) radio telescope resides in a natural valley of Puerto Rico. The Arecibo telescope has been used for many astronomical research projects, including

Crescents of Titan and Dione
29.03.2005

What would it be like to see a sky with many moons? Such is the sky above Saturn. When appearing close to each other, moons will show a similar phase. A view with...

Milky Way in Moonlight
23.04.2016

A waning crescent moon, early morning twilight, and Al Hamra's city lights on the horizon can't hide the central Milky Way in this skyscape from planet Earth. Captured in a single exposure...

On the Origin of Gold
15.10.2017

Where did the gold in your jewelry originate? No one is completely sure. The relative average abundance in our Solar System appears higher than can be made in the early universe, in stars, and even in typical supernova explosions.

Callisto Full Face
20.01.2002

Callisto's surface shows its age. While probably formed at the same time as Io, the difference between the surfaces of these two moons of Jupiter could hardly be greater. Io's surface is young, shows practically no impact craters, and is continually being repaved by the lava exploding from its many large volcanoes

Comet and Aurora Over Alaska
22.04.2002

Can you spot the comet? Flowing across the frozen Alaskan landscape is an easily visible, colorful aurora. Just to the lower left, however, well in the background, is something harder to spot: Comet Ikeya-Zhang, the brightest comet of recent years. Although the aurora faded in minutes, the comet is just now beginning to fade.