Martian Moon Phobos from Mars Express
Why is Phobos so dark? Phobos, the largest and innermost of two Martian moons, is the darkest moon in the entire Solar System. Its unusual orbit and color indicate that it may be a captured asteroid composed of a mixture of ice and dark rock. ...
A Supercell Thunderstorm Cloud Over...
Is that a spaceship or a cloud? Although it may seem like an alien mothership, it's actually a impressive thunderstorm cloud called a supercell. Such colossal storm systems center on mesocyclones -- rotating updrafts that can span several ...
Dark Belt Reappearing on Jupiter
Why are planet-circling clouds disappearing and reappearing on Jupiter? Although the ultimate cause remains unknown, planetary meteorologists are beginning to better understand what is happening. Earlier this year, unexpectedly, Jupiter's dark ...
Anticrepuscular Rays Over Colorado
What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by ...
Star Streams of NGC 4216
Some 40 million light-years distant, edge-on spiral galaxy NGC 4216 is nearly 100,000 light-years across, about the size of our own Milky Way. Found in the dense Virgo Galaxy Cluster, NGC 4216 is centered in this deep telescopic portrait flanked ...
Flame Nebula Close-Up
Of course, the Flame Nebula is not on fire. Also known as NGC 2024, the nebula's suggestive reddish color is due to the glow of hydrogen atoms at the edge of the giant Orion molecular cloud complex some 1,500 light-years away. The hydrogen atoms ...
Stardust in Aries
This composition in stardust covers almost 2 degrees on the sky, close to the border of the zodiacal constellation Aries and the plane of our Milky Way Galaxy. At the lower right of the gorgeous skyscape is a dusty blue reflection nebula ...
Flowing Auroras Over Norway
Have you ever seen an aurora? Auroras are occurring again with increasing frequency. With the Sun being unusually dormant over the past three years, the amount of Sun-induced auroras has also been unusually low. More recently, however, our Sun ...
Gas and Snow Jets from Comet Hartley 2
Unusual jets have been discovered emanating from Comet Hartley 2. The EPOXI spacecraft imaged the jets in unprecedented detail during its flyby of the comet earlier this month. Pictured above, sun-illuminated jets shoot away from the ...
A Dark Dune Field in Proctor Crater...
Was this image taken with a telescope or a microscope? Perhaps this clue will help: if the dark forms were bacteria, they would each span over football field across. What is actually being seen are large sand dunes on the floor of Proctor Crater ...
