05.15.2017 Putting Martian 'Tribulation' Behind
05.15.2017 From 'Tribulation' to 'Perseverance' on Mars
04.20.2017 Chemical Laptop Team
04.20.2017 Subcritical Water Extractor
04.20.2017 Chemical Laptop
04.20.2017 Atacama Landscape
03.30.2017 Measuring Mars' Atmosphere Loss
03.29.2017 Lifetime Achievement Award to Theisinger
03.29.2017 A Decade of Compiling the Sharpest Mars Map
03.21.2017 Break in Raised Tread on Curiosity Wheel
03.17.2017 COBALT/JPL team
03.09.2017 Back-to-Back Martian Dust Storms
02.27.2017 Swirling Dust in Gale Crater, Mars, Sol 1613
02.27.2017 Dust Devil Passes Near Martian Sand Dune
02.27.2017 Sand Moving Under Curiosity, One Day to Next
02.08.2017 Mars Reconnaissance Orbiter Observes Changes
01.26.2017 Mono Lake
01.25.2017 'Wing' Dike of Hardened Lava in New Mexico
01.25.2017 Blade-Like Martian Walls Outline Polygons
01.23.2017 Spirit And Opportunity By The Numbers
01.10.2017 Mars 2020 Rover - Artist's Concept
01.06.2017 Earth and Its Moon, as Seen From Mars
12.13.2016 Now and Long Ago at Gale Crater, Mars
12.13.2016 Where's Boron? Mars Rover Detects It
11.15.2016 Schiaparelli Impact Site on Mars, Stereo
11.03.2016 Schiaparelli Impact Site on Mars, in Color
10.17.2016 MAVEN Captures Rapid Cloud Formation
10.17.2016 Mars' Nightside Atmosphere
10.17.2016 Ultraviolet Image Near Mars' South Pole
10.17.2016 Ultraviolet Mars Reveals Cloud Formation
10.05.2016 Dust Haze Hiding the Martian Surface in 2001
10.04.2016 Test of Lander Vision System for Mars 2020
10.03.2016 A Sharpened Ultraviolet View of Mars
10.03.2016 Curiosity Self-Portrait at 'Murray Buttes'
10.03.2016 Butte 'M9a' in 'Murray Buttes' on Mars
Possible Development Stages of Martian 'Spiders'These five images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter show different Martian features of progressively greater size and complexity, all thought to result from thawing of seasonal carbon-dioxide ice that covers large areas near Mars' south pole during winter.
The sequence illustrates possible stages in development of a type of Martian terrain called "araneiform," from Latin for spider-shaped. They range from a depression with one trough (upper left) to a broad network of "spiders" (lower right). Each image has a scale bar in meters, from 20 meters (66 feet) in the upper-left image to 300 meters (984 feet) in the lower-right one.
Each image also includes dark "fans" that result from the same thawing process. Carbon-dioxide ice, better known as "dry ice," does not occur naturally on Earth. On Mars, sheets of it cover the ground during winter in areas near both poles, including the south-polar regions with spidery terrain. The dark fans appear in these areas each spring.
Spring sunshine penetrates the ice to warm the ground underneath, causing some carbon dioxide on the bottom of the sheet to thaw into gas. The trapped gas builds pressure until a crack forms in the ice sheet. Gas erupts out, and gas beneath the ice rushes toward the vent, picking up particles of sand and dust. This erodes the ground and also supplies the geyser with particles that fall back to the surface, downwind, and appear as the dark spring fans.
These five images are excerpts from HiRISE observations PSP_002718_0950 , taken Feb. 24, 2007, at 85 degrees south latitude, 82 degrees east longitude, and ESP_011842_0980 , taken Feb. 4, 2009, at 81 degrees south latitude, 76 degrees east longitude.
HiRISE is one of six instruments on the Mars Reconnaissance Orbiter, which began examining Mars in 2006. The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter and collaborates with JPL to operate it.
Image Credit: NASA/JPL-Caltech/Univ. of Arizona