Nepal – the country of the Buddha and the Mt. Everest

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Posts Tagged ‘HiRISE’

‘Marsquake’, How Earthquakes On Mars Could Sustain Alien Life (PICTURES)

Posted by Ram Kumar Shrestha on February 25, 2012

 

Recent earthquakes on Mars point at the existence of active volcanoes and liquid reservoirs that could sustain life on the Red Planet.

A recent quake with a magnitude of 7 is thought to have occurred after scientists analysed tracks made by boulders that toppled from a Martian cliff.

The paths of the rocks, which ranged from 6.5 to 65 feet in diameter, were captured by Nasa’s Mars Reconnaissance Orbiter, and were analysed by a University of London team. Read the rest of this entry »

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Nepali Researcher Lujendra Ojha: Briny water may be at work in seasonal flows on Mars

Posted by Ram Kumar Shrestha on August 7, 2011

Dark, finger-like features that appear and extend down some Martian slopes during the warmest months of the Mars year may show activity of salty water on Mars. They fade in winter, then recur the next spring. Repeated observations by the HiRISE camera currently orbiting Mars aboard NASA’s Mars Reconnaissance Orbiter have tracked seasonal changes in these recurring features on several steep slopes in middle latitudes of Mars’ southern hemisphere. Some aspects of the observations still puzzle researchers.

“The best explanation we have for these observations so far is flow of briny water, although this study does not prove that,” said Alfred McEwen of the University of Arizona’s Lunar and Planetary Laboratory. McEwen is the principal investigator for the orbiter’s High Resolution Imaging Science Experiment (HiRISE) and the lead author of a report about the recurring flows published on August 5 by the journal Science.

Other explanations remain possible, but flows of liquid brine fit the features’ characteristics better than alternative hypotheses. Saltiness lowers the temperature at which water freezes. Some sites with the dark flows get warm enough to keep water liquid if it is about as salty as Earth‘s oceans, but temperatures in those areas would not melt pure water ice. Sites with liquid brines could be important to future studies of whether life exists on Mars and to understanding the history of water.

The features are only about 0.5 to 5 yards or meters wide, with lengths up to hundreds of meters. That is much narrower than previously reported gullies on Martian slopes. They have been seen in only about one percent as many locations as larger Mars gullies, but 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 not.

The team first discovered the strange features after University of Arizona student Lujendra Ojha, at the time a junior majoring in geophysics, used a change detection algorithm capable of identifying subtle changes occurring on the Martian surface over time in image pairs during an independent study project.

“I was baffled when I first saw those features in the images after I had run them through my algorithm,” said Ojha, who is a co-author on the Science publication. “We soon realized they were different from slope streaks that had been observed before. These are highly seasonal, and we observed some of them had grown by more than 200 meters in a matter of just two Earth months.” Read the rest of this entry »

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