Aurora Over Clouds
2.04.2001

Aurorae usually occur high above the clouds. The auroral glow is created when fast-moving particles ejected from the Sun impact air molecules high in the Earth's atmosphere. An oxygen molecule, for example, will glow in a green light when reacquiring an electron lost during a collision with a solar particle.

Spiral Galaxy NGC 3310 Across the Visible
11.09.2001

The party is still going on in spiral galaxy NGC 3310. Roughly 100 million years ago, NGC 3310 likely collided with a smaller galaxy causing the large spiral galaxy to light up with a tremendous burst of star formation.

Love and War by Moonlight
24.05.2002

Venus, named for the Roman goddess of love, and Mars, the war god's namesake, approach each other by moonlight in this lovely sky view recorded on May 14th from Dunkirk, Maryland, USA.

Opportunity Rover Indicates Ancient Mars Was Wet
3.03.2004

Was Mars ever wet enough to support life? To help answer this question, NASA launched two rover missions to the red planet and landed them in regions that satellite images indicated might have been covered with water.

Comets Bradfield and LINEAR Rising
3.05.2004

Comet Bradfield is easy to see on the left, but can you find Comet LINEAR on the right? Last week, just before sunrise from the northern hemisphere, two bright comets were visible in the same part of the sky at the same time.

The Tails of Comet NEAT Q4
12.05.2004

Comet NEAT (Q4) is showing its tails. As the large snowball officially dubbed Comet C/2001 Q4 (NEAT) falls toward the inner Solar System, it has already passed the Earth and will reach its closest approach to the Sun this coming Saturday.

Orion Nebula in Oxygen, Hydrogen, and Sulfur
13.07.2004

The Great Nebula in Orion, an immense, nearby starbirth region, is arguably the most famous of all astronomical nebulae. The Orion Nebula, also known as M42, is shown above through ultraviolet and blue filters augmented with three exact colors specifically emitted by hydrogen, oxygen, and sulfur.

Saturn s Infrared Glow
12.10.2006

Known for its bright ring system and many moons, gas giant Saturn looks strange and unfamiliar in this false-color view from the Cassini spacecraft. In fact, in this Visual and Infrared Mapping Spectrometer (VIMS) mosaic the famous rings are almost invisible, seen edge-on cutting across picture center.

Cassini Flyby
26.08.1999

Connect the dots and you'll trace the path of the Cassini spacecraft as it took a final turn by Earth on its way to the outer solar system. The dots (in a horizontal row just below center) are actually successive images of the spacecraft.

Moon Over Andromeda
28.12.2006

The Great Spiral Galaxy in Andromeda (aka M31), a mere 2.5 million light-years distant, is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small...