The Great Pyramids of Giza were originally bright white. When the pyramids were originally finished, they were plated in an outer layer of white “casing stones” which were cut with astounding precision to give a smooth slope to the pyramids, unlike how they appear today with the outer stones more or less forming very large steps. They were made of highly polished Tura limestone, meant to reflect the sun’s rays, and fitting together w an accuracy of 1/100th of an inch.
Named after a 12th century Chinese artist, Xiao Zhao is a young 15-mile (24-kilometer) wide crater on Mercury. Its broad, bright rays indicate its youthfulness, as the lighter material ejected by the initial impact has not yet had enough time to grow dark. “Young” is a relative term, of course. On Mercury that can still mean several billion years old!
In late December an active region on the sun spewed dozens of outbursts over a 36-hour period, including the bright flare and spout of plasma—charged gas—seen in this video still from NASA's Solar Dynamics Observatory. The action was driven by strong magnetic forces on the sun's surface, which can pull against each other violently, triggering bursts of solar material that get hurled into space.
On August 31, 2012 a long filament of solar material that had been hovering in the sun's atmosphere, the corona, erupted out into space. The coronal mass ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly toward Earth, but did connect with Earth's magnetic environment, or magnetosphere, causing aurora to appear on the night of Monday, September 3. Thi is a blended version of the 304 and 171 angstrom wavelengths. (Image Credit: NASA Goddard Space…