An image combining orbital imagery with 3-D modeling shows flows that appear in spring and summer on a slope inside Mars' Newton crater. Sequences of observations recording the seasonal changes at this site and a few others with similar flows might be evidence of salty liquid water active on Mars today. Evidence for that possible interpretation is presented in a report in the Aug. 5, 2011, edition of Science. (NASA)
During warm months on Mars, salty water might run freely down the planet’s slopes.
Scientists are calling saltwater the most likely reason the Martian surface shows dark streaks during its warm seasons. “Finger-like features” appear on Martian terrain during the springtime, according to researchers.
“The best explanation for these observations so far is the flow of briny water,” said Alfred McEwen of the University of Arizona in a statement.
McEwen is the lead author or a report in the journal Science that examines the seasonal flows on Mars. He thinks that since salt lowers the freezing temperature of water, it’s possible that the planet seems liquid flows — perhaps just under its surface.
No signs of water are present on the surface of the slopes, according to data gathered by the Mars Reconnaissance Orbiter.
“The flows are not dark because of being wet,” McEwen said. “They are dark for some other reason.”
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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.
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.
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