Surface
Unlike some the sites visited by the Viking and Pathfinder landers, nearly all the rocks near the Phoenix landing site on Vastitas Borealis are small. For about as far as the camera can see, the land is flat, but shaped into polygons. The polygons are between 2–3 m in diameter and are bounded by troughs that are 20 to 50 cm deep. These shapes are caused by ice in the soil reacting to major temperature changes. The top of the soil has a crust. The microscope showed that the soil is composed of flat particles (probably a type of clay) and rounded particles. When the soil is scooped up, it clumps together. Although other landers in other places on Mars have seen many ripples and dunes, no ripples or dunes are visible in the area of Phoenix. Ice is present a few inches below the surface in the middle of the polygons. Along the edge of the polygons the ice is at least 8 inches deep. When the ice is exposed to the Martian atmosphere it slowly disappears. In the winter there would be accumulations of snow on the surface.
Read more about this topic: Vastitas Borealis
Famous quotes containing the word surface:
“When we are in love, the sentiment is too great to be contained whole within us; it radiates out to our beloved, finds in her a surface which stops it, forces it to return to its point of departure, and it is this rebound of our own tenderness which we call the other’s affection and which charms us more than when it first went out because we do not see that it comes from us.”
—Marcel Proust (1871–1922)
“I cannot but conclude the bulk of your natives to be the most pernicious race of little, odious vermin that Nature ever suffered to crawl upon the surface of the earth.”
—Jonathan Swift (1667–1745)
“In the cold of Europe, under prudish northern fogs, except when slaughter is afoot, you only glimpse the crawling cruelty of your fellow men. But their rottenness rises to the surface as soon as they are tickled by the hideous fevers of the tropics.”
—Louis-Ferdinand Céline (1894–1961)