Tag Archives: water

Martian gullies not formed by water flow

The uncertainty of science: Spectroscopy of many of the gullies on Mars strongly suggests that water had nothing to do with their formation, even though these gullies resemble closely similar gullies on Earth that were carved by flowing water..

Color coding in light blue corresponds to surface composition of unaltered mafic material, of volcanic origin. Mafic material from the crater rim is carved and transported downslope along the gully channels. No hydrated minerals are observed within the gullies, in the data from CRISM, indicating limited interaction or no interaction of the mafic material with liquid water. These findings and related observations at about 100 other gully sites on Mars suggest that a mechanism not requiring liquid water may be responsible for carving these gullies on Mars. (Gullies on Mars are a different type of feature than seasonal dark streaks called recurring slope lineae or RSL; water in the form of hydrated salt has been identified at RSL sites.) [emphasis mine]

In other words, these gullies were formed by flowing lava, not water. Considering Mars’s lower gravity, one third that of Earth’s, we should not be surprised if lava is capable of doing things there that it is not generally capable of doing on Earth. In fact, we should remind ourselves constantly that Mars is an alien planet, and that conditions there are different enough to make any predictions based on our knowledge of Earth very unreliable.

More details here.

Permanently shadowed regions on Ceres

Using data from Dawn scientists have calculated that Ceres could have significant regions on the floors of crater, which are permanently shadowed and which could accumulate water ice.

In this study, Schorghofer and colleagues studied Ceres’ northern hemisphere, which was better illuminated than the south. Images from Dawn’s cameras were combined to yield the dwarf planet’s shape, showing craters, plains and other features in three dimensions. Using this input, a sophisticated computer model developed at NASA’s Goddard Space Flight Center, Greenbelt, Maryland, was used to determine which areas receive direct sunlight, how much solar radiation reaches the surface, and how the conditions change over the course of a year on Ceres.

The researchers found dozens of sizeable permanently shadowed regions across the northern hemisphere. The largest one is inside a 10-mile-wide (16-kilometer) crater located less than 40 miles (65 kilometers) from the north pole. Taken together, Ceres’ permanently shadowed regions occupy about 695 square miles (1,800 square kilometers). This is a small fraction of the landscape — much less than 1 percent of the surface area of the northern hemisphere.

Because Ceres is much farther than the Sun that the Moon or Mercury, the scientists believe it very likely that water ice could have accumulated in these cold traps.

Boiling water on Mars

Scientists now think that the dark streaks they see seasonally develop on Martian slopes are caused when frozen underground water brine is exposed to the atmosphere so that the water boils off, leaving the salt.

More here, including videos of their Earthbound experiments. On Earth, the boiling water caused avalanches and streaks, but because of the higher gravity they were not as long.

More confirmation from Curiosity of past lakes in Gale Crater

New data from Curiosity has now provided further confirmation that the deeper sedimentary layers seen in Gale Crater were likely formed far in the past by flowing water.

“Paradoxically, where there is a mountain today there was once a basin, and it was sometimes filled with water,” said John Grotzinger, the former project scientist for Mars Science Laboratory at the California Institute of Technology in Pasadena, and lead author of the new report. “We see evidence of about 250 feet (75 meters) of sedimentary fill, and based on mapping data from NASA’s Mars Reconnaissance Orbiter and images from Curiosity’s camera, it appears that the water-transported sedimentary deposition could have extended at least 500 to 650 feet (150 to 200) meters above the crater floor.”

Furthermore, the total thickness of sedimentary deposits in Gale Crater that indicate interaction with water could extend higher still, perhaps up to one-half mile (800 meters) above the crater floor.

Above 800 meters, Mount Sharp shows no evidence of hydrated strata, and that is the bulk of what forms Mount Sharp. Grotzinger suggests that perhaps this later segment of the crater’s history may have been dominated by dry, wind-driven deposits, as was once imagined for the lower part explored by Curiosity.

This was always the reason to go and climb Mount Sharp. As Curiosity heads uphill it begins to map out the geological history of Mars, first as a wet place with liquid water, then as a dry place in which the water is gone.

The dark streaks on Mars are water

New data strongly suggests that that the seasonal dark streaks scientists have imaged running down crater slopes on Mars are heavily salted water.

The salt allows the water to flow by lowing its freezing point. The new data has confirmed the presence of those salts, strengthening the theory that the seasonal streaks are water, possibly seeping from beneath the surface or condensing out of the atmosphere.

More evidence found for liquid water on Mars

A new study suggests that a liquid but very salty water does appear on Mars, during the night in the winter and spring months.

The team used Curiosity’s weather-monitoring equipment to look for those conditions and found that they occur every day in months throughout winter and spring. They suggest that overnight and before sunrise, some of the frost that forms on the planet’s surface interacts with the strong salts and turns liquid, seeping into the soil. This lines up with previous studies, which have detected geographic features that suggest flowing water.

The results come from the Gale Crater, which is itself too cold to support microbial life — even with liquid water present. But the study authors believe this phenomenon could occur anywhere on the planet, and may actually be more common in areas closer to the polar regions. Still, Mars is a pretty desolate place, and the amount of water we’re talking about is minimal at best. “There’s so little water that you can’t even see it visibly,” Morten Bo Madsen said.

The hidden glaciers of Mars

The glaciers belts of Mars

Scientists, using computer models and radar data obtained in orbit, have detected large belts of glaciers in Mars’ upper middle latitudes, buried beneath a layer of dust.

Several satellites orbit Mars and on satellite images, researchers have been able to observe the shape of glaciers just below the surface. For a long time scientists did not know if the ice was made of frozen water (H2O) or of carbon dioxide (CO2) or whether it was mud.

Using radar measurements from the NASA satellite, Mars Reconnaissance Orbiter, researchers have been able to determine that is water ice. But how thick was the ice and do they resemble glaciers on Earth? A group of researchers at the Niels Bohr Institute have now calculated this using radar observations combined with ice flow modelling.

The press release has one typo that is important. The belts appear to be located between 30-50 degrees latitude, not 300-500 (the degree sign became a 0 by mistake).

It is important to recognize the uncertainty of this discovery. Orbital images have seen features that suggest glaciers. The evidence that it is water-ice and that the water-ice is still largely present comes from the computer models. Computer models are notorious for seeing things that end up not being there.

Nonetheless, this result is important. It is further strong evidence that Mars still contains a lot of water locked in its immediate subsurface, where future colonists can mine it and use it to survive and build their homes.

The oceans that Mars lost

The lost oceans of Mars

New data from a six year study of the water in the modern Martian atmosphere have allowed scientists to estimate the amount of water Mars once had.

About four billion years ago, the young planet would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometres. “Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, a scientist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, USA, and lead author of the new paper.

The image on the right is an artist’s conception of the oceans that would have existed on Mars, based on modern elevation data.

I must note that this conclusion, the size of the lost Martian ocean, is based on the assumption that the isotope ratios of Martian water started out the same as the Earth’s. While this is a reasonable assumption, it does not have to be true. Nonetheless, these conclusions, using ground-based telescopes, do match up with similar data obtained by Curiosity.

Threatened water shortage on ISS

The crash of Antares and its Cygnus capsule in October has caused the possibility of a water shortage on ISS.

NASA had planned to certify Cygnus to carry water to the space station in early 2015; there were no plans for certifying SpaceX’s Dragon cargo ship to do the same. Orbital plans to launch its next Cygnus aboard a United Launch Alliance Atlas V rocket, but that flight is not scheduled until Nov. 19.

Meanwhile, ESA has ended flights of its ATV cargo ship, which was certified to carry water. With the ATV program over and Cygnus off-line, the space station was left with two vehicles capable of carrying water, the Russian Progress and Japanese HTV.

HTV flights are now limited to once per year; the next one is planned for August 17, just over two weeks before ISS would run out of water on Sept. 2 unless it was resupplied by other vehicles. The schedule provided very little margin for error, ASAP said.

Essentially, if either a Progress or Dragon capsule does not bring additional water to the station before August, and the HTV flight fails or is delayed by more than two weeks, the station will run out of water in early September, requiring its evacuation.

Comet 67P/C-G unveils a scientific surprise

Data from Rosetta of Comet 67P/C-G strongly suggests that the origin of the comets of its class come from a wide range of locations within the early solar system, and that many of these comets might not have delivered the water to Earth as previously believed.

The data also suggests that the Earth’s water came more from asteroids, not comets, something that scientists had not expected.

Exoplanets with no water

The uncertainty of science: Though planet formation theories said they should have water, in looking for water on three exoplanets astronomers were surprised to discover practically none there.

The three planets, known as HD 189733b, HD 209458b, and WASP-12b, are between 60 and 900 light-years away from Earth and were thought to be ideal candidates for detecting water vapor in their atmospheres because of their high temperatures where water turns into a measurable vapor. These so-called “hot Jupiters” are so close to their star they have temperatures between 1,500 and 4,000 degrees Fahrenheit, however, the planets were found to have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories.

“Our water measurement in one of the planets, HD 209458b, is the highest-precision measurement of any chemical compound in a planet outside our solar system, and we can now say with much greater certainty than ever before that we’ve found water in an exoplanet,” said Nikku Madhusudhan of the Institute of Astronomy at the University of Cambridge, England. “However, the low water abundance we have found so far is quite astonishing.” Madhusudhan, who led the research, said that this finding presents a major challenge to exoplanet theory. “It basically opens a whole can of worms in planet formation. We expected all these planets to have lots of water in them. We have to revisit planet formation and migration models of giant planets, especially “hot Jupiters,” and investigate how they’re formed.”

New research suggests that, in general, Mars has always been too cold to harbor liquid water on its surface.

The uncertainty of science: New research suggests that, in general, Mars has always been too cold to harbor liquid water on its surface for long periods.

Mars’ atmosphere was probably never thick enough to keep temperatures on the planet’s surface above freezing for the long term, suggests research published today in Nature Geoscience1. Although the planet’s topography indicates that liquid water has flooded Mars in the distant past, evidence increasingly suggests that those episodes reflect occasional warm spells, not a consistently hospitable phase of the planet’s history.

The research does not say that liquid water never flowed on the Martian surface, only that such events were short-lived. They looked at craters and noted that the surface has impacts from meteorites that would not have survived to the surface had the atmosphere been thick enough for liquid water.

The research however did not address Mars’ relatively smooth northern hemisphere, where there are not a lot of craters and where some scientists think there might once have been a shallow ocean. If Mars never had liquid water for long periods, why does this area lack craters?

New geological research suggests that the hydrogen levels that have detected on the moon — which are used to predict the presence of water — might be a false positive and not exist at the levels predicted.

The uncertainty of science: New geological research suggests that the hydrogen levels that have been detected on the moon — which are used to predict the presence of water — might be a false positive and not exist at the levels predicted.

Instead, what scientists thought was hydrogen in water molecules might be calcium as part of a mineral called apatite. If so, this would mean that the Moon has a lot less water than hoped. This data might also explain the lack of water seen in the Apollo samples as compared to what is suggested should be there from more recent orbital data. This also might explain the conflicting results from instruments on Lunar Reconnaissance Orbiter.

Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.

Astronomers have found evidence of the remains of an exoplanet that they think was once wet and rocky.

Using observations obtained with the Hubble Space Telescope and the large telescopes of the W. M. Keck Observatory , they found an excess of oxygen – a chemical signature that indicates that the debris had once been part of a bigger body originally composed of 26 per cent water by mass. By contrast, only approximately 0.023 per cent of the Earth’s mass is water.

From what I can gather, the actual data here is somewhat skimpy, requring a lot of assumptions for the scientists to come to this conclusion. Nonetheless, the data is interesting and very tantalizing.

Posted from Memphis, Tennessee.

Scientists using data from India’s Chandrayaan-1 space probe have detected new evidence of water inside one crater.

More water on the Moon: Scientists using data from India’s Chandrayaan-1 space probe have detected new evidence of water inside one lunar crater.

What makes this detection important is that this particular water was not placed there by the solar wind or asteroids. Its chemistry suggests it seeped upward from deep within the Moon’s interior.

Opportunity, now moving to another target 1.5 miles away, has found evidence of drinkable water on Mars.

Opportunity, now moving to another target 1.5 miles away, has found evidence that some of the water on Mars was once drinkable.

Before trekking off last month, Opportunity used a grinder to scrape away the top layer of a light-colored rock for a peek inside. The rock was so lumpy and covered with crud that it took the rover several tries to crack open its secrets. Unlike other rocks that Opportunity inspected during the past nine years, the latest told a different story: It contained clay minerals, a sign that water coursed through it, and formed in an environment that might have been suitable for microbes. Previous rock studies by Opportunity pointed to a watery past on Mars, but scientists said the water was acidic.

“This is water you can drink,” said mission chief scientist Steve Squyres of Cornell University.

More details here, noting that this water comes from an earlier time on Mars, when the planet’s environment was more benign.

So the rover has now sampled both sides of the momentous planetary transition from a wet, benign environment more than 4 billion years ago to a colder, drier, harsher one since then

The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.

The lingering echo of Comet Shoemaker-Levy in the atmosphere of Jupiter.

The Herschel observations, together with heat maps provided by NASA’s Infrared Telescope Facility on Mauna Kea, showed the researchers that the Jovian stratosphere was 20° to 30°F (10° to 15°C) warmer than it would be if completely dry. One question is whether the stratospheric warming results from the gentle, continuous infall of interplanetary dust particles, which would be warmed by sunlight as they linger high up. Cavalié and his colleagues believe IDPs create some of the infrared emission but cannot explain it all. Further, a continuously supplied source would migrate to lower depths, yet most of the emission is too high up, at pressures less than 2 millibars. And while the amount of water is roughly constant across the southern hemisphere, the emission gradually weakens northward until it’s less than half as strong. It’s not simply that Jupiter’s bottom half is hotter — there’s just more water down there. As the researchers note, “At least 95% of the observed water comes from the SL9 comet and subsequent (photo)-chemistry in Jupiter’s stratosphere according to our models, as of today.

Taken together, they conclude, these observations offer “clear evidence that a recent comet … is the principal source of water in Jupiter. What we observe today is a remnant of the oxygen delivery by the comet at 44°S in July 1994.”

Data from Mars Reconnaissance Orbiter now suggests that a lake in a Martian crater had filled from groundwater coming up from below.

Data from Mars Reconnaissance Orbiter now suggests that a lake in a Martian crater had filled from groundwater coming up from below.

This is an important discovery, as it demonstrates that an underground water table had existed on Mars, at least at this location. With such a water table, it is possible for all kinds of interesting biological things to have taken place, underground.

Messenger has found new and “compelling” evidence that there is water ice locked in the permanently shadowed craters of Mercury.

Messenger has found new and “compelling” evidence that there is water ice locked in the permanently shadowed craters of Mercury.

On Monday I had spoken to one of the project scientists for this discovery, David Lawrence, in connection with an article I am doing for Astronomy on the evidence of water on the Moon. I knew the Mercury announcement was coming, and asked him for some details. Based on what he told me, it struck me that the evidence for water on Mercury is actually more conclusive than the evidence for the Moon. (In fact, inconclusive nature of the lunar data is the point of my Astronomy article, based on previous posts here and here on Behind The Black.

The more intriguing aspect of this discovery on Mercury, however, is the unknown dark material that covers and protects some of this water ice. That some scientists believe it might even be organic material deposited there by comets and asteroids is most interesting.

The first results from Curiosity’s soil samples have come back.

The first results from Curiosity’s soil samples have come back.

“Much of Mars is covered with dust, and we had an incomplete understanding of its mineralogy,” said David Bish, CheMin co-investigator with Indiana University in Bloomington. “We now know it is mineralogically similar to basaltic material, with significant amounts of feldspar, pyroxene and olivine, which was not unexpected. Roughly half the soil is non-crystalline material, such as volcanic glass or products from weathering of the glass. “

Bish said, “So far, the materials Curiosity has analyzed are consistent with our initial ideas of the deposits in Gale Crater recording a transition through time from a wet to dry environment. The ancient rocks, such as the conglomerates, suggest flowing water, while the minerals in the younger soil are consistent with limited interaction with water.” [emphasis mine]

These results suggest that there has been very little water on the Martian surface for a very long time. They do not, however, mean that there is no water there now.

Scientists have found the source of the water on the Moon and Mercury: the solar wind.

Scientists have found the source of the water on the Moon and Mercury: the solar wind. Key paragraph:

“We found that the ‘water’ component, the hydroxyl, in the lunar regolith is mostly from solar wind implantation of protons, which locally combined with oxygen to form hydroxyls that moved into the interior of glasses by impact melting,” said Zhang, the James R. O’Neil Collegiate Professor of Geological Sciences. “Lunar regolith is everywhere on the lunar surface, and glasses make up about half of lunar regolith. So our work shows that the ‘water’ component, the hydroxyl, is widespread in lunar materials, although not in the form of ice or liquid water that can easily be used in a future manned lunar base.” [emphasis mine]

Though this result would explain the detection of hydrogen on the lunar surface and would also mean that this hydrogen is far less useful for future colonists than previously hoped, it doesn’t eliminate the possibility that there is ice in the permanently shadowed craters near the lunar poles that came from other as yet unknown sources.

Newly released results from Dawn have found evidence of hydrogen on the surface of Vesta

Newly released results from Dawn have found evidence of hydrogen on the surface of Vesta, which also suggests that the asteroid once had water. More here.

The article focuses on the possibility that the hydrogen originally came from ice placed there by icy asteroids. While likely, this remains only one possible explanation.

Mars’ clay minerals might have been formed by volcanic processes, not standing liquid water as generally believed.

The uncertainty of science: Mars’ clay minerals might have been formed by volcanic processes, not standing liquid water as generally believed, according to a new study.

Data collected by orbiting spacecraft show Mars’ clay minerals may instead trace their origin to water-rich volcanic magma, similar to how clays formed on the Mururoa atoll in French Polynesia and in the Parana basin in Brazil. That process doesn’t need standing bodies of liquid water. “The infrared spectra we got in the lab (on Mururoa clays) using a reflected beam are astonishingly similar to that obtained on Mars by the orbiters,” lead researcher Alain Meunier, with the University of Poitiers in France, wrote in an email to Discovery News. The team also points out that some of the Mars meteorites recovered on Earth do not have a chemistry history that supports standing liquid water.

If correct, this alternative explanation would mean that Mars was not that wet in the past, and would have been far less likely of ever having sustained life.

Water Ice in Shackleton Crater?

Ice in Shackleton?

New results from the radar instrument on Lunar Reconnaissance Orbiter (LRO) has found evidence of water-ice on the slopes of Shackleton Crater, located at the Moon’s south pole. The paper, published on Saturday in Geophysical Research Letters – Planets, suggested that about 5 to 10 percent of the weight of the material on the slopes of the crater is comprised of water ice, to depths of 6 to 10 feet.

The box on the upper left in the image to the right shows the data from a radar sweep of the crater taken on April 18, 2010, and compares that to five computer models. As you can see, the data here most closely matches the 5% ice model. Two other sweeps showed similar results.

The water-ice, if there, is not in slabs of ice, as sometimes portrayed in the press, but would be mixed into the Moon’s regolith, or “topsoil”, and would have to be processed out like ore to be useful. Or to quote the paper’s conclusion:

The fundamental conclusions made with high resolution, ground based radar of Shackleton remain unaltered — that no large-scale, meters thick ice deposits are evident within the crater. Rather, Mini-RF data are consistent with roughness effects or with a small percentage of water-ice deposits admixed into the uppermost 1-2 meters of silicate regolith within Shackleton, possibly accounting for the observations made by the Clementine bistatic experiment.

Several points:
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