Subscribe free to our newsletters via your
. Space Travel News .




MARSDAILY
ASU instruments help scientists probe ancient Mars atmosphere
by Staff Writers
Tempe AZ (SPX) Sep 03, 2015


An area named Nili Fossae contains the richest deposit of carbonate minerals on Mars. If the carbon dioxide in its rocks were released, it would about triple the density of Mars' present atmosphere. New work using data from ASU instruments and others on NASA orbiters suggests that either Mars has yet-undiscovered reservoirs of carbonate rocks - or the planet may have seen flowing water despite having a thin, cold atmosphere. This THEMIS image uses false colors to show where the surface has loose materials such as sand or gravel (cool colors) and where the ground is tougher and rockier (warm tones). The scale bar is 12 miles long. Image courtesy NASA/JPL-Caltech/Arizona State University. For a larger version of this image please go here.

Mars was not always the arid Red Planet that we know today. Billions of years ago it was a world with watery environments - but how and why did it change? A new analysis of the largest known deposit of carbonate minerals on Mars helps limit the range of possible answers to that question.

The Martian atmosphere currently is cold and thin - about 1 percent of Earth's - and almost entirely carbon dioxide. Yet abundant evidence in the form of meandering valley networks suggests that long ago it had flowing rivers that would require both a warmer and denser atmosphere than today. Where did that atmosphere go?

Carbon dioxide gas can be pulled out of the Martian air and buried in the ground by chemical reactions that form carbonate minerals. Once, many scientists expected to find large deposits of carbonates holding much of Mars' original atmosphere. Instead, instruments on space missions over the past 20 years have detected only small amounts of carbonates spread widely plus a few localized deposits.

The instruments searching for Martian carbonate minerals include the mineral-detecting Thermal Emission Spectrometer (TES) on NASA's Mars Global Surveyor orbiter and the Thermal Emission Imaging System (THEMIS) on NASA's Mars Odyssey orbiter. THEMIS' strength lies in measuring and mapping the physical properties of the Martian surface.

Both instruments were designed by Philip Christensen, Regents' Professor of geological sciences in ASU's School of Earth and Space Exploration. TES fell silent when NASA lost contact with Mars Global Surveyor in 2006, but THEMIS remains in operation today.

"We designed these instruments to investigate Martian geologic history, including its atmosphere," Christensen said. "It's rewarding to see data from all these instruments on many spacecraft coming together to produce these results."

Other instruments involved in the search include the mineral-mapping Compact Reconnaissance Imaging Spectrometer for Mars and two telescopic cameras on NASA's Mars Reconnaissance Orbiter.

Big, but not big enough
By far the largest known carbonate-rich deposit on Mars covers an area at least the size of Delaware, and maybe as large as Arizona, in a location called Nili Fossae. But its quantity of carbonate minerals comes up short for what's needed to produce a thick atmosphere, according to a new paper just published online in the journal Geology.

The paper's lead author is Christopher Edwards, a former graduate student of Christensen's. He is now with the U.S. Geological Survey in Flagstaff, Arizona. Both TES and THEMIS contributed to the work, he said.

"The Thermal Emission Spectrometer told us how much Nili has of several kinds of minerals, especially carbonates," Edwards noted.

And, he added, "THEMIS played an essential complementary role by showing the physical nature of the rock units at Nili. Were they impact-shattered small rocks and soil? Were they fractured and cemented rocks? Or dunes? THEMIS data let us differentiate these units by composition."

Bethany Ehlmann of the California Institute of Technology and NASA's Jet Propulsion Laboratory is Edwards' co-author. She said Nili doesn't measure up to what's needed. "The biggest carbonate deposit on Mars has, at most, twice as much carbon within it as the current Mars atmosphere.

"Even if you combined all known carbon reservoirs together," she explained, "it is still nowhere near enough to sequester the thick atmosphere that has been proposed for the time when there were rivers flowing on the Martian surface."

Edwards and Ehlmann estimate that Nili's carbonate inventory, in fact, falls too short by at least a factor of 35 times. Given the level of detail in orbital surveys, the team thinks it highly unlikely that other large deposits have been overlooked.

Atmosphere going, going, gone
So where did the thick ancient atmosphere go?

Scientists are looking at two possible explanations. One is that Mars had a much denser atmosphere during its flowing-rivers period, and then lost most of it to outer space from the top of the atmosphere, rather than into minerals and rocks. NASA's Curiosity Mars rover mission has found evidence for ancient top-of-atmosphere loss, but uncertainty remains just how long ago this happened. NASA's MAVEN orbiter, examining rates of change in the outer atmosphere of Mars since late 2014, may help reduce the uncertainty.

An alternative explanation, favored by Edwards and Ehlmann, is that the original Martian atmosphere had already lost most of its carbon dioxide by the era of rivers and valleys.

"Maybe the atmosphere wasn't so thick by the time the valley networks formed," Edwards suggested. "Instead of Mars that was wet and warm, maybe it was cold and wet with an atmosphere that had already thinned."

How warm would it need to have been for the valleys to form? It wouldn't take much, Edwards said.

"In most locations, you could have had snow and ice instead of rain. You just have to nudge above the freezing point to get water to thaw and flow occasionally, and that doesn't require very much atmosphere."


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Arizona State University
Mars News and Information at MarsDaily.com
Lunar Dreams and more






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





MARSDAILY
What Happened to Early Mars' Atmosphere
Pasadena CA (JPL) Sep 03, 2015
Scientists may be closer to solving the mystery of how Mars changed from a world with surface water billions of years ago to the arid Red Planet of today. A new analysis of the largest known deposit of carbonate minerals on Mars suggests that the original Martian atmosphere may have already lost most of its carbon dioxide by the era of valley network formation. "The biggest carbonate depos ... read more


MARSDAILY
SpaceX delays next launch after blast

Proton-M Brings Satellite Into Orbit for First Time Since May Accident

US Launches Atlas V Rocket With Navy Communications Satellite After Delay

FCube facility enters operations with fueling of Soyuz Fregat upper stage

MARSDAILY
Opportunity brushes a rock and conducts in-situ studies

ASU instruments help scientists probe ancient Mars atmosphere

What Happened to Early Mars' Atmosphere

Destination Red Planet: Will Billionaires Fund a Private Mars Colony

MARSDAILY
Russia Gets Ready for New Moon Landing

ASU chosen to lead lunar CubeSat mission

Russia's moon landing plan hindered by financial distress

Research May Solve Lunar Fire Fountain Mystery

MARSDAILY
New Horizons Team Selects Potential Kuiper Belt Flyby Target

Scientists study nitrogen provision for Pluto's atmosphere

Flowing nitrogen ice glaciers seen on Pluto

New Horizons 'Captures' Two of Pluto's Smaller Moons

MARSDAILY
Distant planet's interior chemistry may differ from our own

Earth's mineralogy unique in the cosmos

A new model of gas giant planet formation

Planetary pebbles were building blocks for the largest planets

MARSDAILY
Green Propellant Infusion Mission Receives Propulsion System

NASA Funds Plasma Rocket Technology for Superfast Space Travel

Need for Speed: Star Trek Warp Drive is Within Our Grasp

NASA Considers Using Old Water Tanks in New ISS Storage System

MARSDAILY
Progress for Tiangong 2

China rocket parts hit villager's home: police, media

China's "sky eyes" help protect world heritage Angkor Wat

China's space exploration potential has US chasing its own tail

MARSDAILY
Comet Hitchhiker Would Take Tour of Small Bodies

Dawn Sends Sharper Scenes from Ceres

UA Cameras Give Sight to NASA's OSIRIS-REx Mission

Rosetta hits 'milestone' in comet's run past Sun




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.