Auf dem Mars fliesst Wasser

Taev

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Gerade gelesen --

Forscher haben Hinweise darauf gefunden, dass es auf dem Mars flüssiges Wasser gibt. Für die Suche nach Leben ist der Fund von grosser Bedeutung.

Auf dem Mars gibt es wahrscheinlich auch heute noch flüssiges Wasser. Darauf deuten neue Analysen von Messdaten der Raumsonde «Mars Reconnaissance Orbiter» (MRO) der US-Raumfahrtbehörde Nasa hin.

Salziges Schmelzwasser könnte demnach regelmässig im Marssommer manche Steilhänge hinabfliessen, wie Forscher um Lujendra Ojha vom Georgia Institute of Technology in Atlanta im Fachblatt «Nature Geoscience» berichten. Die Analysen sind der bislang beste Beleg dafür, dass es auch heute noch zumindest zeitweise flüssiges Wasser auf dem Roten Planeten gibt.

Flüssiges Wasser ist von zentraler Bedeutung für Leben, wie wir es kennen. Auf dem Mars wurden bereits verschiedene Wassereisvorkommen und zahlreiche Hinweise auf ausgetrocknete Gewässer gefunden. Flüssiges Wasser selbst hingegen wurde bislang nicht direkt beobachtet. Seine Entdeckung hätte Bedeutung für die Suche nach vergangenem oder womöglich noch existierendem Leben auf dem Planeten.

Auch für die bemannte Raumfahrt zum Mars wäre flüssiges Wasser von enormer Wichtigkeit. Doug McCuistion, der ehemalige Leiter des Nasa-Marsprogramms, sagte dem «Boston Herald», dass es eine der Hauptherausforderungen sei, genügend Wasser und Sauerstoff zu finden, um eine Crew auf dem Mars zu versorgen. «Wenn es schon dort wäre und man es nicht hinbringen müsste, würde das viele, viele Tonnen Nachschub sowie anfängliche Frachtkapazität und Landemasse einsparen», so McCuistion.
Quelle: 20 Minuten - Auf dem Mars fliesst Wasser - News


Der Artikel ist noch länger, habe nur den ersten Teil hier rein kopiert -- schon cool, bin gespannt ob und was sich da noch findet :)
 

Taev

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Salt Water May Flow on Mars

August 4, 2011: Observations from NASA's Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on Mars.

Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere.

"The best explanation for these observations so far is the flow of briny water," said Alfred McEwen of the University of Arizona, Tucson. McEwen is the principal investigator for the orbiter's High Resolution Imaging Science Experiment (HiRISE) and lead author of a report about the recurring flows published in Thursday's edition of the journal Science.

Some aspects of the observations still puzzle researchers, but flows of liquid brine fit the features' characteristics better than alternate hypotheses. Saltiness lowers the freezing temperature of water. Sites with active flows get warm enough, even in the shallow subsurface, to sustain liquid water that is about as salty as Earth's oceans, while pure water would freeze at the observed temperatures.

"These dark lineations are different from other types of features on Martian slopes," said Mars Reconnaissance Orbiter Project Scientist Richard Zurek of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Repeated observations show they extend ever farther downhill with time during the warm season."

The features imaged are only about 0.5 to 5 yards or meters wide, with lengths up to hundreds of yards. The width is much narrower than previously reported gullies on Martian slopes. However, some of those locations display more than 1,000 individual flows. Also, while gullies are abundant on cold, pole-facing slopes, these dark flows are on warmer, equator-facing slopes.

The images show flows lengthen and darken on rocky equator-facing slopes from late spring to early fall. The seasonality, latitude distribution and brightness changes suggest a volatile material is involved, but there is no direct detection of one. The settings are too warm for carbon-dioxide frost and, at some sites, too cold for pure water. This suggests the action of brines, which have lower freezing points. Salt deposits over much of Mars indicate brines were abundant in Mars' past. These recent observations suggest brines still may form near the surface today in limited times and places.

When researchers checked flow-marked slopes with the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), no sign of water appeared. The features may quickly dry on the surface or could be shallow subsurface flows.

"The flows are not dark because of being wet," McEwen said. "They are dark for some other reason."

A flow initiated by briny water could rearrange grains or change surface roughness in a way that darkens the appearance. How the features brighten again when temperatures drop is harder to explain.

"It's a mystery now, but I think it's a solvable mystery with further observations and laboratory experiments," McEwen said.

These results are the closest scientists have come to finding evidence of liquid water on the planet's surface today. Frozen water, however has been detected near the surface in many middle to high-latitude regions. Fresh-looking gullies suggest slope movements in geologically recent times, perhaps aided by water. Purported droplets of brine also appeared on struts of the Phoenix Mars Lander. If further study of the recurring dark flows supports evidence of brines, these could be the first known Martian locations with liquid water.

"NASA's Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form,” NASA Administrator Charles Bolden said, “and it reaffirms Mars as an important future destination for human exploration."

For more information about the Mars Reconnaissance Orbiter, visit: Mars Reconnaissance Orbiter MRO | NASA and Mars Reconnaissance Orbiter
Quelle: Salt Water May Flow on Mars - NASA Science
 

Ezri

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Cool :up aber bei dem Wort "Wassereisvorkommen" musste ich dann doch direkt denken: "Und welche Geschmacksrichtung? :eis" :haha
 
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