page_title: Extraterrestrial sky
section_title: The color of the Martian sky
hierarchical_section_title: Extraterrestrial sky / Mars / The color of the Martian sky
caption_attribution_description: English: Mosaic of MastCam pictures taken by the MSL/Curiosity rover on Mars, on Sols 170 and 176 of its mission (27 January and 3 February 2013), giving an "Impression Soleil Couchant" on Mars with real colors and the Martian sky having its delicate blue halo just above the Sun. Image reconstructed from real color imaging data: only the position of the Sun was added because the original image there was overexposed.
context_page_description: In astronomy, an extraterrestrial sky is a view of outer space from the surface of an astronomical body other than Earth.
  The only extraterrestrial sky that has been directly observed and photographed by astronauts is that of the Moon. The skies of Venus, Mars and Titan have been observed by space probes designed to land on the surface and transmit images back to Earth.
  Characteristics of extraterrestrial sky appear to vary substantially due to a number of factors. An extraterrestrial atmosphere, if present, has a large bearing on visible characteristics. The atmosphere's density and chemical composition can contribute to differences in colour, opacity and the presence of clouds. Astronomical objects may also be visible and can include natural satellites, rings, star systems and nebulas and other planetary system bodies.
context_section_description: Generating accurate true-color images from Mars's surface is surprisingly complicated. To give but one aspect to consider, there is the Purkinje effect: the human eye's response to color depends on the level of ambient light; red objects appear to darken faster than blue objects as the level of illumination goes down. There is much variation in the color of the sky as reproduced in published images, since many of those images have used filters to maximize their scientific value and are not trying to show true color. For many years, the sky on Mars was thought to be more pinkish than it is now believed to be.
  It is now known that during the Martian day, the sky is a butterscotch color.  Around sunset and sunrise, the sky is rose in color, but in the vicinity of the setting Sun it is blue. This is the opposite of the situation on Earth.  Twilight lasts a long time after the Sun has set and before it rises because of the dust high in Mars's atmosphere.
  On Mars, Rayleigh scattering is usually a very weak effect; the red color of the sky is caused by the presence of iron(III) oxide in the airborne dust particles. These particles are larger in size than gas molecules, so most of the light is scattered by Mie scattering. Dust absorbs blue light and scatters longer wavelengths (red, orange, yellow).
caption: Mars sky at sunset, as imaged by the Curiosity rover (February 2013; Sun simulated by artist)
exif: {}