As noted in the post, the dunes surround Mars' northern
polar cap and were created by gusts of wind. The image below shows an area
(80.3 degrees north latitude, 172.1 degrees east longitude) that's 19 miles
wide — though the dunes reportedly cover an area as large as the state of
Texas.
This particular scene was taken with the infrared camera of
the Mars Odyssey orbiter, called the Thermal Emission Imaging System (THEMIS).
One of the most striking aspects of the photo is the vivid
coloring seen throughout the dunes. As NASA described, the varying colors in
this false-color image correspond with different dune temperatures.
As NASA explained in another post, the THEMIS "measures
the surface temperature day and night, allowing scientists to determine what
physical materials, such as rock, sand, or dust, exist. Its data reveals the
presence of these materials based on how they heat up or cool down over the
course of a Martian day."
The post goes on to note that in addition to helping
scientists create maps of Mars, the THEMIS allows them to identify the presence
of everything from sandstone to salts. Laura Kerber of NASA's Jet Propulsion
Laboratory, who works as Odyssey's deputy project scientist, was quoted saying,
"It's hard to overstate how the THEMIS global map has filled gaps in our
knowledge."
The blue dunes photo above combines images taken from the
orbiter during Dec. 2002 and Nov. 2004. It's just one of a historic collection
of images compiled to celebrate the Odyssey's 20th anniversary.
The Odyssey launched from Florida's Cape Canaveral Air Force
Station on April 7, 2001, and it entered the Mars orbit that October. It
remains in orbit 19-plus years later, which makes it the longest-working Mars
spacecraft in history. - Mashable
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