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Explanation: How does your favorite planet spin? Does it spin rapidly around a nearly vertical axis, or horizontally, or backwards? The featured video animates NASA images of all eight planets in our Solar System to show them spinning side-by-side for an easy comparison. In the time-lapse video, a day on Earth -- one Earth rotation -- takes just a few seconds. Jupiter rotates the fastest, while Venus spins not only the slowest (can you see it?), but backwards. The inner rocky planets across the top underwent dramatic spin-altering collisions during the early days of the Solar System. Why planets spin...

Explanation: Waiting years and traveling kilometers -- all to get a shot like this. And even with all of this planning, a good bit of luck was helpful. As the Sun rose over the Baltic Sea last Wednesday as seen from Fehmarn Island in northern Germany, photographer Jens Hackmann was ready for the very unusual black dot of Venus to appear superimposed. Less expected were the textures of clouds and haze that would tint different levels of the Sun various shades of red. And possibly the luckiest gift of all was a flicker of a rare green flash at the...

Explanation: The rare transit of Venus across the face of the Sun in 2004 was one of the better-photographed events in sky history. Both scientific and artistic images flooded in from the areas that could see the transit: Europe and much of Asia, Africa, and North America. Scientifically, solar photographers confirmed that the black drop effect is really better related to the viewing clarity of the camera or telescope than the atmosphere of Venus. Artistically, images might be divided into several categories. One type captures the transit in front of a highly detailed Sun. Another category captures a double coincidence...

WDoomsday, schmoomsday. Why settle for dusty ol' Mayan calendars and 12/12/12 apocalyptic visions, when 2012 has been offering up so many stellar—and planetary—sightings? We Earthlings have already been treated to nice meteor showers as well as a magnificent supermoon, and this weekend brings an annular solar eclipse. ~snip~ That's not even the best treat: Venus will be ambling between Earth and the sun in a rare (though non-earth-shattering) planetary alignment. ~snip~ A solar eclipse happens this Sunday, except for the Eastern seaboard (sorry). It's an "annular" eclipse rather than a total one, which means the sun's edges peek out from...

Explanation: Sister planet stands / together with sister stars. / Celebrate the sky.

Explanation: After wandering about as far from the Sun on the sky as Venus can get, the brilliant evening star crossed paths with the Pleiades star cluster earlier this week. The beautiful conjunction was enjoyed by skygazers around the world. Taken on April 2, this celestial group photo captures the view from Portal, Arizona, USA. Also known as the Seven Sisters, even the brighter naked-eye Pleiades stars are seen to be much fainter than Venus. And while Venus and the sisters do look star-crossed, their spiky appearance is the diffraction pattern caused by multiple leaves in the aperture of the...

Explanation: What just above that ridge? The Moon. Specifically, the Earth's Moon was caught just above the horizon in a young crescent phase. The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth. Also captured in the image is the bright planet Venus on the right. Venus and Jupiter passed only three degrees from each other last week during a photogenic planetary conjunction. The above image was taken two days ago near Madrid, Spain. The foreground horizon silhouette includes...

The Moon and Venus

Explanation: The rare transit of Venus across the face of the Sun in 2004 was one of the better-photographed events in sky history. Both scientific and artistic images flooded in from the areas that could see the transit: Europe and much of Asia, Africa, and North America. Scientifically, solar photographers confirmed that the black drop effect is really better related to the viewing clarity of the camera or telescope than the atmosphere of Venus. Artistically, images might be divided into several categories. One type captures the transit in front of a highly detailed Sun. Another category captures a double coincidence...