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Blobrana


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RE: Mars
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A putative view of the primordial Mars.
 


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Blobrana


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Mars caves
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Pits Near Alba Patera

marspits1
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Credit: NASA/JPL/University of Arizona

This image shows pits in Acheron Catena, a chain of circular depressions located southeast of Alba Patera, the widest and flattest volcano on Mars. The layers seen around the pit rims (approximately 350 meters across) are likely lava flows from Alba Patera or the nearby Tharsis Mons.
The pits probably formed by collapse into empty space beneath the surface as opposed to being formed by an impactor from space. Some of the pits have large piles of material in their centers. These piles are evidence of collapse of the walls, which may have occurred after the main collapse event that formed each pit. The second pit from the right has an indistinct north rim; it appears that there were at least two collapse events here.

Latitude (centred): 36.8 ° Longitude (East): 258.8 °

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Blobrana


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RE: Mars
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Mars, now cooled into crusty sphere, once sizzled with oceans of magma for millions of years. New research suggests it was red-hot tens of millions of years longer than previously thought.
Rare chunks of Martian rock flung to Earth as meteorites hint at an extended molten status, for which scientists think a thick, early atmosphere was responsible.

"The most recent physical models for magma oceans suggest they solidify on timescales of a few million years or less, so this result is surprising" - Alan Brandon, a geochemist at NASA's Johnson Space Centre in Houston.

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Blobrana


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Mars was covered in an ocean of molten rock for about 100 million years after the planet formed, researchers from the Lunar and Planetary Institute in Houston, Texas, UC Davis, and NASA's Johnson Space Centre have found. The work is published in the journal Nature on Nov. 22.
The formation of the solar system can be dated quite accurately to 4,567,000,000 years ago, said Qing-Zhu Yin, assistant professor of geology at UC Davis and an author on the paper. Mars' metallic core formed a few million years after that. Previous estimates for how long the surface remained molten ranged from thousands of years to several hundred million years.
The persistence of a magma ocean on Mars for 100 million years is "surprisingly long," Yin said. It implies that at the time, Mars must have had a thick enough atmosphere to insulate the planet and slow down cooling, he said.

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Blobrana


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Martian caves
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If Mars looks like a primordial Earth-on-ice, the similarity ends just below the surface where Martian caves are borne not of slow dripping processes but from brief, intensely violent times, say researchers.
It's meteor impacts and volcanoes which are thought to make Martian caves. Lava tubes, like those found near Earth's volcanoes, have been recently identified from Mars orbiting spacecraft. While melted ice by meteor impacts may create all the ingredients for bursts of cavern formation around the impact zone.
Both types of caves offer one very attractive feature to prospective Martian life that the Martian surface lacks - protection from the barely filtered solar and cosmic radiation that bombards Mars' surface.

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Blobrana


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Seven very dark holes on the north slope of a Martian volcano have been proposed as possible cave skylights, based on day-night temperature patterns suggesting they are openings to subsurface spaces. These six excerpts of images taken in visible-wavelength light by the Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter show the seven openings. Solar illumination comes from the left in each frame. The volcano is Arsia Mons, at 9 degrees south latitude, 239 degrees east longitude.

Marscaves
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Credit: NASA/JPL-Caltech/ASU/USGS

The features have been given informal names to aid comparative discussion. They range in diameter from about 100 meters to about 225 meters. The candidate cave skylights are (A) "Dena," (B) "Chloe," (C) "Wendy," (D) "Annie," (E) "Abby" (left) and "Nikki," and (F) "Jeanne." Arrows signify north and the direction of illumination.

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Blobrana


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Martian caves
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NASA's Mars Odyssey spacecraft has discovered entrances to seven possible caves on the slopes of a Martian volcano. The find is fuelling interest in potential underground habitats and sparking searches for caverns elsewhere on the Red Planet.
Very dark, nearly circular features ranging in diameter from about 328 to 820 feet puzzled researchers who found them in images taken by NASA's Mars Odyssey and Mars Global Surveyor orbiters. Using Mars Odyssey's infrared camera to check the daytime and nighttime temperatures of the circles, scientists concluded that they could be windows into underground spaces.

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Blobrana


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Tiu Valles
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The mysterious ridges at the mouth of Tiu Valles
 
Tiu Valles
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Tiu Valles

These images taken by the High Resolution Stereo Camera (HRSC) on board Mars Express show the mouth of the Tiu Valles channel system on the red planet.The mouth of Tiu Valles is an estuary-like landform. On Earth, an estuary is the tidal mouth of a river valley, or the end that meets the sea and fresh water comes into contact with seawater. In such an area, tidal effects are evident.
The pictures were taken in orbit 3103 on 10 June 2006 with a ground resolution of approximately 16 metres per pixel.

Tiu Valles is located at approximately 27° North and 330° East. The sun illuminates the scene from the North West, the lower left-hand side in the image.
Tiu Valles originates in the equatorial chaotic terrains at the mouth, at the eastern end of Valles Marineris. The morphology of this chaotic terrain is dominated by large-scale remnant massifs, which are large relief masses that have been moved and weathered as a block. These are randomly oriented and heavily eroded.
From there, the region extends to the north over a distance of 1500 km before terminating in Chryse Planitia. Along with Kasei Valles and Ares Valles, Tiu Valles is one of the major outflow channels entering the Chryse Planitia plain.

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Blobrana


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RE: Mars meteorites
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The identification and study of five meteorites on the surface of Mars by NASA's twin rovers Spirit and Opportunity has presented a fresh mystery about the possible presence of surface water in the past.

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Blobrana


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A study of the thermodynamics of clays found on Mars suggests that little carbon dioxide could have been present during their formation, which contradicts a popular theory of the early Martian atmosphere and will send researchers looking for other explanations for clay formation.
Vincent Chevrier of the University of Arkansas and François Poulet and Jean-Pierre Bibring of the Université Paris-Sud in Orsay, France, reported their findings in the journal Nature.
Gullies, valleys and clay formations found on Mars seem to point to a wet past for the Red Planet. Almost all clays formed on earth do so in the presence of water or under extremely humid conditions. These clay remnants of ancient Mars had previously led scientists to hypothesise that the earliest era on the planet, the Noachian period, had a carbon-dioxide-rich atmosphere that created a warm, wet surface with liquid water -- ideal for creating clays.
Chevrier used thermodynamic calculations to examine possible historic conditions on the planet. These calculations look at the equilibrium conditions of the clay deposits on Mars with respect to different relevant other mineral phases -- carbonates, sulphates, iron oxides -- to extrapolate the surface environment at the time of their formation. He made the assumption that the clays would form on the surface of Mars in the presence of liquid water as they do on Earth.
In a carbon-dioxide-rich environment, clay formation would be accompanied by carbonate formation, but current studies of Mars have found no such compounds. Chevrier's calculations show that, given current conditions, the carbon dioxide pressure would have been low in the Noachian atmosphere.

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