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This HiRISE observation shows the northwest quadrant of a fracture-filled crater on Mars.
NASA/JPL/University of Arizona
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Top 10 Space Stories of 2015: Readers' Choice
PHOTOS: Weirdest Mars Craters Spotted by HiRISE
The entire crater is around 3 miles (5 km) across and its ancient interior has undergone countless millennia of freeze/thaw cycles that have broken the surface into polygonal shapes. This process is common on Mars and can even be found on Earth, but this particular image depicts it exceptionally nicely.
The fractured surface polygons can be seen to get more compressed nearer to the crater’s rim. The image description by the HiRISE team explains:
The crater rim constrains the polygon
formation within the crater close to the rim, creating a spoke and ring
pattern of cracks. This leads to more rectangular polygons than those
near the center of the crater. The polygons close to the center of the
crater display a more typical pattern. A closer look shows some of these
central polygons, which have smaller polygons within them, and smaller
polygons within those smaller polygons, which makes for a natural
fractal!
PHOTOS: NASA Spacecraft’s Epic 10 Years of MarsA full map-projected scan of the area is below:
Polygonal terrain within and around a polar crater on Mars (monochrome red-filter HiRISE image.)
NASA/JPL-Caltech/University of Arizona
PHOTOS: Mind-Blowing Beauty of Mars’ Dunes
HiRISE is capable of resolving structures on Mars’ surface down to about a meter in size from its location in orbit. The image above was acquired from a distance of 196 miles (314 km). You can see many more images from HiRISE here.
: HiRISE Photos
Jan 14, 2014 01:40 PM ET
//
Mars plays host to a huge number of dune fields -- regions
where fine wind-blown material gets deposited to form arguably some of
the most beautiful dunes that can be found on any planetary body in the
solar system. Using the powerful High-Resolution Imaging Science
Experiment (HiRISE) camera on board NASA's Mars Reconnaissance Orbiter,
planetary scientists have an orbital view on these features that aid our
understanding of aeolian (wind-formed) processes and Martian geology. Here are some of our favorite Mars dunes as seen by HiRISE.
Pictured here are shell-like "barchan dunes" in the ancient Noachis Terra region of Mars.
Special thanks to Ari Espinoza of the HiRISE team at the University of Arizona for helping to compile this list.
PHOTOS: The Weirdest Craters on Mars
Pictured here are shell-like "barchan dunes" in the ancient Noachis Terra region of Mars.
Special thanks to Ari Espinoza of the HiRISE team at the University of Arizona for helping to compile this list.
PHOTOS: The Weirdest Craters on Mars
NASA/JPL-Caltech/University of Arizona
Dunes of many shapes, sizes and formation processes can be found on the Red Planet. Shown here are elegant "linear dunes" with deposits of larger rocks and possibly ices in their troughs.
READ MORE: Sand Dunes Could Reveal Weather on Alien Worlds
READ MORE: Sand Dunes Could Reveal Weather on Alien Worlds
NASA/JPL-Caltech/University of Arizona
These slug-like dark dunes are striking examples of "dome dunes"
-- elliptical accumulations of fine material with no-slip surfaces.
These domes contrast greatly with the often jagged appearance of barchan
dunes. Found at the bottom of Proctor Crater, they are darker than the
surrounding crater floor as they are composed of dark basaltic sand that
was transported by the wind.
READ MORE: Slug-Like Dunes on Mars
READ MORE: Slug-Like Dunes on Mars
NASA/JPL-Caltech/University of Arizona
Looking like a wind-blown silk sheet, this field of "star
dunes" overlays a plain of small ripples, another aeolian feature. The
ripples move more slowly across the bottom of Proctor Crater, so the
large dune field will travel over the smaller ripples. Dunes
are continuously evolving and moving with the wind, ensuring that the
Martian surface is never static.
READ MORE: Bouncing Sands of Mars Blow in the Wind
READ MORE: Bouncing Sands of Mars Blow in the Wind
NASA/JPL-Caltech/University of Arizona
These "transverse dunes" are undergoing seasonal changes.
Likely entering Mars summer, this region of dunes is stained with
pockets of subliming ices -- likely carbon dioxide. As the ices turn
from solid to vapor, dune material slumps, revealing dark, sandy
material underneath.
NASA/JPL-Caltech/University of Arizona
Resembling the mouths of a shoal of feeding fish, this is a
group of barchan dunes in Mars' North Polar region. Barchan dunes
betray the prevailing wind direction. In this case, the prevailing wind
is traveling from bottom right to top left; the steep slope of material
(plus dune "horns") point to the downwind direction. The HiRISE camera
monitors barchans to see if they move between observing opportunities,
thereby revealing their speed of motion across the Martian plains.
NASA/JPL-Caltech/University of Arizona
This is the same barchan dune field, zoomed out, a "swarm" of dunes covering the plains.
NASA/JPL-Caltech/University of Arizona
Not all barchan dunes "behave" and form neat "horny"
shapes. They can become muddled and overlapping, creating "barchanoid
dunes," as shown here.
NASA/JPL-Caltech/University of Arizona
This very fluid-looking collection of barchans is accompanied by a wind-blown ridge in the Hellespontus region of Mars but...
NASA/JPL-Caltech/University of Arizona
...only when zoomed out does the true nature of this
fascinating region become clear. The prevailing wind is eroding the
mesas (small hills) to the right of the image, carrying fine material
downwind (from right to left), creating a startling pattern of barchans
and a viscous-looking trail of sandy ridges across the plains.
NASA/JPL-Caltech/University of Arizona
The band Train sang about the "Drops of Jupiter" -- what
about the "Drops of Mars"? Sure, they're not made of any kind of fluid,
but they do make for incredibly-shaped dunes. These raindrop-shaped
dunes are found in Copernicus Crater and are known to be rich in the
mineral olivine, a mineral that formed during the wet history of Mars'
evolution.
READ MORE: Mars' 'Raindrop' Sand Dunes Swarm
READ MORE: Mars' 'Raindrop' Sand Dunes Swarm
NASA/JPL-Caltech/University of Arizona
These craggy-looking dunes are old barchanoids eroding
away through seasonal processes (sublimation of sub-surface ices) and
the persistent Martian wind.
NASA/JPL-Caltech/University of Arizona
These linking barchan dunes are at the leading edge of a
dune field -- grains of dust have been blown across a plain, deposited
and left to accumulate in elongated arrow shapes.
NASA/JPL-Caltech/University of Arizona
Dome-shaped dunes and barchans seem to "reach out" and touch their downwind partners with slumped material.
NASA/JPL-Caltech/University of Arizona
Barchan dunes inside Arkhangelsky Crater in the southern
hemisphere of Mars reveal a wind direction from top left to bottom
right. Note the tracks of Martian dust devils over the dune slopes.
For more on the HiRISE camera, see the HiRISE website and regularly updated Tumblr page. For more on Mars dune definitions, check out the USGS Mars Dunes site.
For more on the HiRISE camera, see the HiRISE website and regularly updated Tumblr page. For more on Mars dune definitions, check out the USGS Mars Dunes site.
NASA/JPL-Caltech/University of Arizona
Space X Falcon 9's vertical landing
| NDTV | - |
| The Indian Express | - |
SpaceX's
Falcon 9 rocket entered into space, deployed satellites, and then
landed back on Earth successfully which is an important milestone in
space technology.
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