Astronomy Picture Of the Day (APOD)Sprite Lightning at 100000 Frames Per Second
What causes sprite lightning? Mysterious bursts of light in the sky that momentarily resemble gigantic jellyfish have been recorded for over 30 years, but apart from a general association with positive cloud-to-ground lightning, their root cause remains unknown. Some thunderstorms have them -- most don't.
A Phoenix Aurora over Iceland
All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet September night, much of that night's auroras had died down. Suddenly, unexpectedly, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again.
21st Century Wet Collodion Moon
In the mid 19th century, one of the first photographic technologies used to record the lunar surface was the wet-plate collodion process, notably employed by British astronomer Warren De la Rue. To capture...
Galaxies and the South Celestial Pole
The South Celestial Pole is easy to spot in star trail images of the southern sky. The extension of Earth's axis of rotation to the south, it's at the center of all the southern star trail arcs.
Trail of the Returner
Familiar stars of a northern winter's night shine in this night skyview, taken near Zhangye, Gansu, China and the border with Inner Mongolia. During the early hours of December 17 Orion is near...
Jupiter and Saturn Great Conjunction: The Movie
Yes, but have you seen a movie of Jupiter and Saturn's Great Conjunction? The featured time-lapse video was composed from a series of images taken from Thailand and shows the two giant planets as they angularly passed about a tenth of a degree from each other.
Earth During a Total Solar Eclipse
What does the Earth look like during a total solar eclipse? It appears dark in the region where people see the eclipse, because that's where the shadow of the Moon falls. The shadow...
M16: Inside the Eagle Nebula
From afar, the whole thing looks like an Eagle. A closer look at the Eagle Nebula, however, shows the bright region is actually a window into the center of a larger dark shell of dust. Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed.
Cosmic Latte: The Average Color of the Universe
What color is the universe? More precisely, if the entire sky were smeared out, what color would the final mix be? This whimsical question came up when trying to determine what stars are commonplace in nearby galaxies. The answer, depicted above, is a conditionally perceived shade of beige. In computer parlance: #FFF8E7.
Fox Fur, Unicorn, and Christmas Tree
Clouds of glowing hydrogen gas fill this colorful skyscape in the faint but fanciful constellation Monoceros, the Unicorn. A star forming region cataloged as NGC 2264, the complex jumble of cosmic gas and dust...