The stories you want. The opinions that matter.
No, thanks
Tag: space exploration
Water Still Flows On Mars, Scientists Say

Water Still Flows On Mars, Scientists Say

By Amina Khan, Los Angeles Times (TNS)

Where there’s brine, there’s water.

Scientists scouring the Red Planet using NASA’S Mars Reconnaissance Orbiter say they’ve found direct chemical evidence of transient saltwater flowing on the surface today.

Granted, they haven’t caught the liquid in the act — and what they’ve detected looks less like salty water and more like watery salt. But nonetheless, the discovery published by the journal Nature Geoscience helps solve a long-standing Martian mystery and sheds light on the potential for life on our nearest planetary neighbor.

“This is the first time we’ve found flowing water on a planet that’s not ours,” said lead author Lujendra Ojha, a planetary scientist and Ph.D. candidate at Georgia Tech.

Scientists got a tantalizing hint that there could be liquid water on the surface back in 2011, when Alfred McEwen, lead scientist for the Mars Reconnaissance Orbiter’s HiRISE camera, along with Ojha and other colleagues, discovered these strange dark streaks on Martian slopes that seem to grow and fade with the seasons. These “recurring slope lineae,” which can stretch up to a few meters, extend downward when it gets warm and then later shrink and fade, reappearing each Martian year.

“Ever since the discovery in 2011 … a number of us have been incredibly excited by the prospect of liquid water on Mars,” said Bethany Ehlmann, a planetary geologist at Caltech who was not involved in the paper. Nonetheless, she added, “we try to be cautious — it’s a big thing to say there’s liquid water on Mars today.”

Granted, Mars’ atmosphere is cold and thin — which means that any pure water that made it to the surface would either freeze or immediately evaporate, depending on the temperature. But a recent study by scientists using NASA’s Curiosity rover found that water might indeed be able to exist briefly on the surface — provided there were enough salts, such as perchlorates, dissolved in the liquid. These salts would keep the water from freezing or evaporating quite as easily and could actually serve to suck moisture back out of the air.

So could liquid water — very salty, briny water — really explain these strange dark streaks on Martian slopes?

Theoretically, the scientists could look for water by using the orbiter’s Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM. CRISM can look for different chemicals in a given spot on the surface by studying the telltale signature of dark bands they’ve left in the light. The problem is, it’s hard to check the light’s chemical fingerprint at the recurring slope lineae, or RSL, because, according to the study, “few locations exist in which RSL are wide or dense enough to fill even a single CRISM pixel.”

So researchers used a method where they focused on the handful of individual pixels that were mostly filled by the recurring slope lineae. They looked at four different spots with recurring slope lineae and discovered a strong fingerprint for hydrated salts — salts with water locked into the mineral structure, a clear sign that saltwater likely had flowed there. The hydrated salts included magnesium perchlorate, magnesium chlorate and sodium perchlorate.

The findings may further whet the appetite of astrobiologists looking to probe past habitable environments on the Red Planet, researchers said.

“I think it’s incredibly exciting, because when we look back at the broad scope of Mars history, it’s always in the past where there’s evidence for the most water,” Ehlmann said. “But if there’s liquid water even today, when Mars is supposedly at its driest … I think that says that there was probably liquid water for all of the last 4.5 billion years, just like there was on Earth. Not in the same quantity, but at least ephemerally, episodically, it’s there.”

Still, the water is so incredibly briny that it’s difficult to imagine microbes being able to survive with the harsh fluid.

In the meantime, where exactly the water comes from, how it’s released, and how it gets back into the soil to repeat the cycle every year remain open questions, the scientists said. Such questions could be answered by a future orbiting mission to Mars, Ehlmann added.

(c)2015 Los Angeles Times. Distributed by Tribune Content Agency, LLC.

Portions of the Martian surface shot by NASA’s Mars Reconnaissance Orbiter show many channels from 1 meter to 10 meters wide on a scarp in the Hellas impact basin, in this photograph taken January 14, 2011 and released by NASA March 9, 2011. REUTERS/NASA/JPL-Caltech/Univ. of Arizona/Handout

Mars Rover Curiosity Offers Tantalizing Taste Of 2-Tone Mineral Veins

Mars Rover Curiosity Offers Tantalizing Taste Of 2-Tone Mineral Veins

By Amina Khan, Los Angeles Times (TNS)

Climbing up Mt. Sharp in the middle of Gale Crater, NASA’s Mars rover Curiosity has discovered a two-tone vein of minerals that reveal multiple episodes of water flowing through rock — even after the lake that once filled the bottom of the crater had ceased to be.

The rover’s discovery points to an even more complex, and perhaps long-lived, watery environment on the Red Planet.

“Not only does this help us try to understand the chemistry of the rocks that we measure in the region, but on a different sort of scale it tells us that fluids were around on Mars for a long time,” said Linda Kah, a sedimentary geologist at the University of Tennessee, Knoxville, and a member of Curiosity’s science team.

The duo-tone deposits, at a spot called Garden City, sit some 39 feet above the lower edge of the Pahrump Hills outcrop, which is part of the basal layer of the 3-mile-high Mt. Sharp. They feature both light and dark regions. They rise about 2.5 inches above the rock surface like ridges, because the rock that once surrounded them has worn away. These kinds of veins are formed when fluid flows through cracks in a rock and leaves some minerals behind.

Most veins have been bright and light-colored, Kah said, often filled with calcium sulfate. On Earth, such mineral deposits are often associated with salty water. But the dark deposits were somewhat unexpected, she said.

The dark parts often seem to line either side of the white veins, rather like an ice cream sandwich — a description Kah’s 10-year-old son Douglas came up with while looking over his mother’s shoulder at images of the deposits.

“I think they’re incredibly gorgeous and beautiful,” she said.

Whether appetizing or attractive, the two different tones are scientifically telling. Researchers look at Martian rocks in part to see how water (and the stuff in the water) may have affected a particular rock during a particular era. But if the same rock is getting soaked with very different kinds of water sources over time, then it may show a confusing mix of traits from a long period in which the environment dramatically changed over and over again.

That’s why the mineral veins are so helpful. The deposits in the cracks can look very different from the surrounding rock because they were formed much later than the rock itself. So while the rock’s chemistry and mineralogy will have been affected by multiple environments, the mineral vein offers a snapshot of at least one individual era in the Red Planet’s history.

In this case, this mineral vein actually offers snapshots into three environments. At first the scientists thought there were two different epochs, represented by the light and dark deposits, but it turns out that some dark spots are chemically very different from other dark areas.

“It was really very exciting for us,” Kah said. “Now we’ve just added complexity, so it makes it more fun to figure it out in the long run.”

The scientists think this environment existed long after the lake that once filled the bottom of Gale Crater dried up for good, and that these deposits were created by water under a significant amount of rock — enough to exert the kind of pressure that would force the fluid to push through cracks in the stone.

It’s also unclear how hot or cold or acidic or salty this water was; the fluid’s chemistry could have been very different from the potentially potable liquid in that long-gone lake.

But it’s still quite possible that microbial life, if it ever existed, could have thrived in this environment, just as they thrive in the rock fractures at the hot springs of Yellowstone National Park, she added.

(c)2015 Los Angeles Times, Distributed by Tribune Content Agency, LLC

Image Credit: NASA/JPL-Caltech/MSSS

NASA’s Mars Rover Curiosity Finally Arrives At Mount Sharp

NASA’s Mars Rover Curiosity Finally Arrives At Mount Sharp

By Amina Khan, Los Angeles Times

After wandering in the Martian desert for 25 months, NASA’s Curiosity rover has finally arrived at its promised land: the base of Mount Sharp, the 3-mile-high mound in the middle of Gale Crater.

The arrival marks the beginning of the Mars Science Laboratory rover’s original mission: to read the mountain’s clay-rich lower layers like pages in a history book, pages that could reveal an array of life-friendly environments on the Red Planet.

“We have finally arrived at the far frontier that we have sought for so long,” project scientist and California Institute of Technology geologist John Grotzinger said Thursday.

Getting to Mount Sharp has been a long time coming. The trip was delayed in part by a detour the rover took to look at a promising spot called Yellowknife Bay. Although it cost the team at Jet Propulsion Laboratory about half a year, the gamble paid off; rocks drilled there revealed a smorgasbord of chemical elements that would have been suitable for microbial life, if it ever existed.

Now that the scientists know habitable environments did exist on the Red Planet, part of the next step will be looking for those particular environments that have a higher likelihood of preserving organic molecules, Grotzinger said.

The rover is closing in on a spot known as Pahrump Hills, an outcrop that wasn’t on the original itinerary — a happy outcome of the detour Curiosity took to avoid sharp rocks that had been causing an alarming amount of damage on the rover’s thin wheels. This spot will now be the gateway to Mount Sharp, and it probably holds Curiosity’s first official drilling target. Grotzinger said the rover would make it there in the next week or two.

The scientists are particularly interested in a stretch of rock known as the Murray Formation, which it will cross en route to its original stopping point, Murray Buttes. Kathryn Stack, Curiosity rover mission scientist, pointed out that the Murray Formation could provide an unprecedented wealth of information about the history of habitable environments on Mars. After all, the Yellowknife Bay formation where Curiosity found its first life-friendly spot was only 5 meters thick, representing perhaps thousands to hundreds of thousands of years of sedimentary deposits. The Murray Formation, by contrast, is 200 meters thick.

“We potentially have millions to tens of millions of years of Martian history just waiting for us to explore,” Stack said.

The hard part, scientists said, will be deciding how much time to devote to Pahrump Hills, Murray Buttes and the next interesting unit up the slopes, called Hematite Ridge. Grotzinger said he was particularly interested in the silicon in the upcoming rocks, because the element’s distribution can often signal the movement of water.

Mission officials also responded to criticism from a NASA Planetary Senior Review panel report released this summer. The report contended that the plan to explore Mount Sharp did not make good use of the rover’s instruments, calling it “a poor science return for such a large investment in a flagship mission.”

“I think the principal recommendation of the panel is that we drive less and drill more,” Grotzinger said, and he said that’s not far from what they are going to end up doing. “I think that the recommendations of the review and what we want to do as a science team are going to align, because we have now arrived at Mount Sharp, we are going to do a lot more drilling.”

Photo via WikiCommons

Interested in national news? Sign up for our daily email newsletter!

Mars Rover Opportunity Breaks The Off-World Driving Record

Mars Rover Opportunity Breaks The Off-World Driving Record

By Amina Khan, Los Angeles Times

Opportunity, the little rover that could, has broken a 41-year-old driving distance record that’s out of this world. The decade-old NASA Mars rover has crossed the 25-mile mark, surpassing the 24.2-mile record held by the Russian moon rover Lunokhod 2.

Not too shabby for a rover that landed on the Red Planet in 2004 with a 90-day mission and an odometer geared for a roughly 0.6-mile drive, said John Callas, the mission’s project manager at NASA’s Jet Propulsion Laboratory in La Canada Flintridge, Calif.

“No one in their wildest dreams thought the rover would last this long,” Callas said. “People made bets early on — ‘Maybe we can get to the first Martian winter,’ ‘Maybe we can get two years out of it’ — but no one thought that it would last this long.”

No one’s betting against Opportunity now. It may be aging, with an arthritic elbow and a somewhat disabled front wheel, but it has long outlived its twin rover, Spirit, and lasted roughly 40 times as long as it was supposed to.

The previous record-holder for distance, the Lunokhod 2, was sent loping around the moon’s surface by Russia in 1973. It covered 24.2 miles in less than five months — speedy compared with Opportunity’s 10-plus years. But NASA’s Martian rover was the tortoise to Lunokhod 2’s hare, slowly and inexorably closing the distance.

Opportunity’s extra miles have allowed its handlers to make remarkable discoveries, because the robotic explorer has been able to venture far outside its landing site. Though it discovered hints of past water soon after landing in Eagle Crater, the water was acidic and unsuitable for life. Only after leaving its landing site and arriving at Endeavour Crater did the rover discover signs of neutral, drinkable water — a key ingredient for life-friendly environments.

If Opportunity can do about 1.2 more miles, it will reach Marathon Valley (so named because it marks the 26.2-mile point). The valley holds layers of rock rich in clay that could give new insight into the Red Planet’s geologic story. In that way, it’s a little like Mount Sharp, the 3-mile-high mound in the middle of Gale Crater targeted by NASA’s bigger, more advanced Mars rover, Curiosity, which touched down in 2012. Curiosity’s tools could help it read the mountain’s clay-rich layers like pages in a book, whose chapters could reveal ancient, life-friendly environments.
But in some ways, Callas said, Opportunity’s target is even better.

Mount Sharp will give Curiosity a window on Mars as it was about 3.5 billion years ago. But Marathon Valley’s layers could show Opportunity what the Red Planet looked like about 4 billion, even up to 4.5 billion years ago.

“The geology is older and more significant in terms of establishing the early habitability of Mars,” Callas said. The clays could come from very early days, he said, a time when Mars could have been warm and wet — with similar conditions to early Earth when life here first began to emerge.

And even though Curiosity’s high-tech tool belt will allow it to explore its target in ways that Opportunity cannot, there’s no knocking the “classical field geology” the older rover can do with its cameras and its rock abrasion tool, Callas said — analogous to a human geologist’s eyes and trusty rock hammer.

So when will Opportunity finally kick the bucket?

“You know, no one really knows. The only thing I can say is that with each passing day we get a bit closer to that end,” Callas said. “It could happen at any moment … or it could just keep plodding along. So we treat each day as a valuable day and keep exploring.”

Photo via WikiCommons

Interested in national news? Sign up for our daily email newsletter!