NASA's Curiosity rover photographed a cloudy sunset on the planet Mars on March 19. The image consists of 21 individual pictures, stitched and in a corrected color, so that the scene appears as the human eye would see.
As described in the NASA post, in the Martian sky were observed "bursts of clouds filled with ice crystals that scatter the light from the setting sun, some of which shimmer in color ”.
According to NASA, clouds are rare in the thin atmosphere of Mars, but usually form at the equator, during the coldest time of the year. Scientists have observed that last year (two years ago according to the time on Earth) there were clouds starting to form earlier than expected, so this year they were ready to observe them.
The images are not only impressive, but gave new information to NASA's Curiosity team. The first clouds are at higher altitudes than most Martian clouds, which typically hover about 60 kilometers above the planet's surface and are composed of water ice. Higher altitude clouds are probably made of frozen carbon dioxide or dry ice, according to NASA.
NASA's poetic description is also impressive: Shortly after sunset, the ice crystals caught the fading light, making them appear to glow in the dark sky. These twilight clouds, also known as “noctilucent” (Latin for “night glows”), grow larger and brighter as they fill with crystals, then darken when the position of Heliumy in the sky falls below an altitude.
Mark Lemmon, a scientist at the Space Science Institute in Boulder, Colorado, said in a NASA publication that these colors come from cloud particles of almost identical size. "This usually happens because as soon as the clouds form, they all grow at the same rate."
Lemmon said the colors that appear in these clouds are red, green, blue and purple. "It's very nice to see something shining on Mars, with a lot of color."
