Astronomy Picture Of the Day (APOD)Colors of Mercury
The colors of the solar system's innermost planet are enhanced in this tantalizing view, based on global image data from the Mercury-orbiting MESSENGER spacecraft. Human eyes would not discern the clear color differences but they are real none the less, indicating distinct chemical, mineralogical, and physical regions across the cratered surface.
Snow Moon for a Snowy Planet
The alarmingly tall inhabitants of this small, snowy planet cast long shadows in bright moonlight. Of course, the snowy planet is actually planet Earth and the wide-angle mosaic, shown as a little planet projection, was recorded on February 25 during the long northern night of the Full Snow Moon.
Asperatus Clouds Over New Zealand
What kind of clouds are these? Although their cause is presently unknown, such unusual atmospheric structures, as menacing as they might seem, do not appear to be harbingers of meteorological doom. Known informally...
Coronal Rain on the Sun
Does it rain on the Sun? Yes, although what falls is not water but extremely hot plasma. An example occurred in mid-July 2012 after an eruption on the Sun that produced both a Coronal Mass Ejection and a moderate solar flare. What was more unusual, however, was what happened next.
Fly Me to the Moons
Sometimes the Moon is a busy direction. Last week, for example, our very Moon passed in front of the planet Jupiter. While capturing this unusual spectacle from New South Wales, Australia, a quick-thinking astrophotographer...
M51: The Whirlpool Galaxy in Dust and Stars
The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky.
Chelyabinsk Meteor Flash
A meteoroid fell to Earth on February 15, streaking some 20 to 30 kilometers above the city of Chelyabinsk, Russia at 9:20am local time. Initially traveling at about 20 kilometers per second, its explosive deceleration after impact with the lower atmosphere created a flash brighter than the Sun.
Curiosity Self Portrait Panorama
This remarkable self-portrait of NASA's Mars Curiosity Rover includes a sweeping panoramic view of its current location in the Yellowknife Bay region of the Red Planet's Gale Crater. The rover's flat, rocky perch, known as "John Klein", served as the site for Curiosity's first rock drilling activity.
How would you change the course of an Earth-threatening asteroid? One possibility - a massive spacecraft that uses gravity as a towline - is illustrated in this artist's vision of a gravitational tractor in action.
Saturns Hexagon and Rings
Why would clouds form a hexagon on Saturn? Nobody is sure. Originally discovered during the Voyager flybys of Saturn in the 1980s, nobody has ever seen anything like it anywhere else in the Solar System.