Dust and Dust Devil Tracks
Large portions of the martian surface are blanketed with bright reddish-ochre dust. The dust particles are typically less than 40 micrometres in size and are composed of iron oxide minerals. Data from the Thermal Emission Spectrometer (TES) on the Mars Global Surveyor spacecraft has allowed planetary scientists to estimate the amount of dust cover for broad swaths of the planet. In general, the Diacria quadrangle is extremely dusty, particularly in Arcadia Planitia and the region around the flank of Alba Mons and the Olympus Mons aureole in the southeastern portion of the quadrangle. A few large patches of relatively low dust cover occur in Amazonis Planitia and in the northwest corner of the quadrangle.
Many areas on Mars, including the Diacria quadrangle, experience the passage of giant dust devils. When a dust devil goes by it blows away the coating of dust and exposes the underlying dark surface. Dust devils have been seen from the ground and high overhead from orbit. They have even blown the dust off of the solar panels of the two Rovers on Mars, thereby greatly extending their lives. The twin Rovers were designed to last for 3 months, instead they both lasted more than six years, and one is still going. The pattern of the tracks have been shown to change every few months.
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Milankovic Crater central area, as seen by HiRISE. Click on image to see more details: dark dunes, beautiful dust devil tracks, and boulders (small bright dots).
Read more about this topic: Diacria Quadrangle
Famous quotes containing the words dust, devil and/or tracks:
“And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.”
—Bible: Hebrew Genesis 2:7.
“Will mankind never learn that policy is not morality,—that it never secures any moral right, but considers merely what is expedient? chooses the available candidate,—who is invariably the devil,—and what right have his constituents to be surprised, because the devil does not behave like an angel of light? What is wanted is men, not of policy, but of probity,—who recognize a higher law than the Constitution, or the decision of the majority.”
—Henry David Thoreau (1817–1862)
“I long ago lost a hound, a bay horse, and a turtle-dove, and am still on their trail. Many are the travellers I have spoken concerning them, describing their tracks and what calls they answered to. I have met one or two who had heard the hound, and the tramp of the horse, and even seen the dove disappear behind a cloud, and they seemed as anxious to recover them as if they had lost them themselves.”
—Henry David Thoreau (1817–1862)