Astronomy Picture Of the Day (APOD)Saturns Moons Dione and Titan from Cassini
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...
Ash and Lightning Above an Icelandic Volcano
Why did the recent volcanic eruption in Iceland create so much ash? Although the large ash plume was not unparalleled in its abundance, its location was particularly noticeable because it drifted across such well populated areas.
Large Eruptive Prominence Imaged by STEREO
What's happened to our Sun? Last week, it produced one of the most power eruptive prominences ever seen. Pictured above, the prominence erupted in only a few hours and was captured in movie form by NASA's twin Sun-orbiting STEREO satellites.
Damage to Apollo 13
After an oxygen tank exploded and crippled their service module, the Apollo 13 astronauts were forced to abandon plans to make the third manned lunar landing. The extent of the damage is revealed...
Bright Points on the Quiet Sun
Up close, the solar surface is a striking patch work of granules in this very high resolution picture of the quiet Sun. Caused by convection, the granules are hot, rising columns of plasma edged by dark lanes of cooler, descending plasma.
NGC 4651: The Umbrella Galaxy
Spiral galaxy NGC 4651 is a mere 35 million light-years distant, toward the well-groomed constellation Coma Berenices. About 50 thousand light-years across, this galaxy is seen to have a faint umbrella-shaped structure (right) that seems to extend some 50 thousand light-years farther, beyond the bright galactic disk.
A Large Space Station Over Earth
The International Space Station is the largest object ever constructed by humans in space. The station perimeter now extends over roughly the area of a football field, although only a small fraction of this is composed of modules habitable by humans.
Unusual Spiral Galaxy M66 from Hubble
Why isn't spiral galaxy M66 symmetric? Usually density waves of gas, dust, and newly formed stars circle a spiral galaxy's center and create a nearly symmetric galaxy. The differences between...
Mercury and Venus Over Paris
Go outside tonight and see one of the more interesting planetary conjunctions of recent years. Just after sunset, the planets Mercury and Venus are visible quite near each other. Now Venus, being commonly discernible as one of the brightest objects in the sky, is frequently mistaken for an airplane.
IC 418: The Spirograph Nebula
What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing tool, planetary nebula IC 418 shows patterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours.