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Curiosity rover spies colorful iridescent clouds on Mars
The Curiosity rover has witnessed a colorful marvel on Mars: Shining clouds.
Color is rare in this frozen desert, apart from the predominant red. But in the skies above Curiosity, the clouds appear to almost sparkle with color.
Unlike Earth, Mars doesn’t have many overcast, cloudy days. The red planet has a thin, dry atmosphere, so clouds tend to appear in the skies over the Martian equator when the planet is cold and farthest from the sun in its oval-shaped orbit every two Earth years .
That changed two Earth years, or one Martian year, ago when Curiosity spotted clouds that arrived earlier and formed higher in the atmosphere than expected.
Most clouds on Mars hover no more than about 37 miles (60 kilometers) in the sky and are made of frozen water. But these shimmering clouds photographed by the Curiosity Rover sit at a higher altitude, where the air is much colder. This likely means that the higher clouds are made from frozen carbon dioxide.
The Curiosity’s panoramic Mast Camera, or Mastcam, captured the clouds just after sunset, showing ice crystals that were able to catch the fading light and appeared to shine against the sky.
“These twilight clouds, also known as “noctilucent” (Latin for “night shining”) clouds, grow brighter as they fill with crystals, then darken after the Sun’s position in the sky drops below their altitude,” the lab said. “This is just one useful clue scientists use to determine how high they are.”