LRO Makes a Map of the Moon’s Water

The Moon might seem like a poor place to hunt for water, but in fact there’s a decent amount of the stuff dispersed throughout the lunar soil — and even more of it existing as ice deposits in the dark recesses of polar craters. While the LCROSS mission crashed a rocket stage into one of these craters in October 2009 and confirmed evidence of water in the resulting plume of debris, there haven’t been any definitive maps made of water deposits across a large area on the Moon — until now.

Over the course of several years, NASA’s Lunar Reconnaissance Orbiter scanned the Moon’s south pole using its Lunar Exploration Neutron Detector (LEND) to measure how much hydrogen is trapped within the lunar soil. Areas exhibiting suppressed neutron activity — shown above in blue — indicate where hydrogen atoms are concentrated most, strongly suggesting the presence of water molecules… aka H2O.

The incredibly-sensitive LEND instrument measures the flux of neutrons from the Moon, which are produced by the continuous cosmic ray bombardment of the lunar surface. Even a fraction of hydrogen as small as 100 ppm can make a measurable change in neutron distribution from the surface of worlds with negligible atmospheres, and the hydrogen content can be related to the presence of water.

No other neutron instrument with LEND’s imaging capability has ever been flown in space.

Watch the video below for more details as to how LRO and LEND obtained these results:

“While previous lunar missions have observed indications of hydrogen at the Moon’s south pole, the LEND measurements for the first time pinpoint where hydrogen, and thus water, is likely to exist.”

What’s so important about finding water on the Moon? Well besides helping answer the question of where water on Earth and within the inner Solar System originated, it could also be used by future lunar exploration missions to produce fuel for rockets, drinking water, and breathable air. Read more here.

Video credit: NASA Goddard Space Flight Center

Curiosity Once Again in Safe Mode – If Only Briefly

Not even two and a half weeks after a memory glitch that sent NASA’s Curiosity rover into a safe mode on Feb. 27, the robotic Mars explorer once again went into standby status as the result of a software discrepancy — although mission engineers diagnosed the new problem quickly and anticipate having the rover out of safe mode in a couple of days.

“This is a very straightforward matter to deal with,” said Richard Cook, project manager for Curiosity at Jet Propulsion Laboratory in Pasadena. “We can just delete that file, which we don’t need anymore, and we know how to keep this from occurring in the future.”

Via a JPL press release, issued March 18:

“Curiosity initiated this automated fault-protection action, entering ‘safe mode’ at about 8 p.m. PDT (11 p.m. EDT) on March 16, while operating on the B-side computer, one of its two main computers that are redundant to each other. It did not switch to the A-side computer, which was restored last week and is available as a back-up if needed. The rover is stable, healthy and in communication with engineers.

“The safe-mode entry was triggered when a command file failed a size-check by the rover’s protective software. Engineers diagnosed a software bug that appended an unrelated file to the file being checked, causing the size mismatch.”

 The rover is stable, healthy and in communication with engineers.

– NASA’s Jet Propulsion Laboratory

Once Curiosity is back online its investigation into the watery history of Gale crater will resume, but another hiatus — this one planned — will commence on April 4, when Mars will begin passing behind the Sun from Earth’s perspective. Mission engineers will refrain from sending commands to the rover during a four-week period to avoid data corruption from solar interference.

Keep up with the latest news from the MSL mission here.

Then again, there’s a certain personality on Twitter who claims a slightly different reason for these recent setbacks…

Sarcastic Rover

 

A Hi-Res Mosaic of Mercury’s Crescent

A view of Mercury from MESSENGER’s October 2008 flyby (NASA / JHUAPL / Gordan Ugarkovic)

Every now and then a new gem of a color-composite appears in the Flickr photostream of Gordan Ugarkovic, and this one is the latest to materialize.

This is a view of Mercury as seen by NASA’s MESSENGER spacecraft during a flyby in October 2008. The image is a composite of twenty separate frames acquired with MESSENGER’s narrow-angle camera from distances ranging from 18,900 to 17,700 kilometers and colorized with color data from the spacecraft’s wide-angle camera. (North is to the right.)

Click the image for a closer look, and for an even bigger planet-sized version click here. Beautiful!

The images that made up this mosaic were taken two and a half years before MESSENGER entered orbit around Mercury on March 19, 2011 UT, becoming the first spacecraft ever to do so and making Mercury the final “classical” planet to be orbited by a manmade spacecraft.

Since that time MESSENGER has completed well over 1,000 orbits and taken more than 100,000 images of the first planet in the Solar System, which filled in most of our gaps in Mercury’s map and showed us many never-before-seen features of the planet’s Sun-scoured surface. And just this past year MESSENGER’s extended mission helped confirm what could be called its most important discovery of all: water ice on Mercury’s north pole.

2012_Year_Highlights-1This was even selected by Scientific American as one of the Top 5 Space Stories of 2012.

With all that’s been achieved by MESSENGER in 2011 and 2012, 2013 is looking to be an interesting year!

“We learned a great deal about Mercury over the past year,” said MESSENGER Principal Investigator Sean Solomon of Columbia University’s Lamont-Doherty Earth Observatory. “The team published three dozen scientific and technical papers and delivered more than 150 presentations at national and international meetings. New measurements continue to stream back from our spacecraft, and we can look forward with excitement to many additional discoveries in 2013.”

Follow the MESSENGER mission news here and see more of Gordan’s space images here.

Inset image: 12 Mercurial discoveries by MESSENGER in 2012. Click to review.

The Moon’s Water Comes From the Sun

An image of water-filled debris ejected from Cabeus crater about 20 seconds after the 2009 LCROSS impact. Courtesy of Science/AAAS.

Comets? Asteroids? The Earth? The origins of water now known to exist within the Moon’s soil — thanks to recent observations by various lunar satellites and the impact of the LCROSS mission’s Centaur rocket in 2009 — has been an ongoing puzzle for scientists. Now, new research supports that the source of at least some of the Moon’s water is the Sun, with the answer blowing in the solar wind.


Spectroscopy research conducted on Apollo samples by a team from the University of Tennessee, University of Michigan and Caltech has revealed “significant amounts” of hydroxyl within microscopic glass particles found inside lunar soil, the results of micrometeorite impacts.

According to the research team, the hydroxyl “water” within the lunar glass was likely created by interactions with protons and hydrogen ions from the solar wind.

“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 Youxue Zhang, Professor of Geological Sciences at the University of Michigan.

Hydroxyl is the pairing of a single oxygen atom to a single hydrogen atom (OH). Each molecule of water contains two hydroxyl groups.

Although such glass particles are widespread on the surface of the Moon — the researchers studied samples returned from Apollo 11, Apollo 16 and Apollo 17 missions — the water in hydroxyl form is not something that could be easily used by future lunar explorers. Still, the findings suggest that solar wind-derived hydroxyl may also exist on the surface of other airless worlds, like Mercury, Vesta or Eros… especially within permanently-shadowed craters and depressions.

“These planetary bodies have very different environments, but all have the potential to produce water,” said Yang Liu, University of Tennessee scientist and lead author of the team’s paper.

The discovery of hydroxyl within lunar glasses presents an “unanticipated, abundant reservoir” of water on the Moon, and possibly throughout the entire Solar System.

The study was published online Sunday in the journal Nature Geoscience.

Source: University of Michigan news release.

Inset image: a grain of lunar agglutinate glass from samples returned by Apollo astronauts (Yang Liu)

A River Ran Through It: Why Do They Think There Was Once Water on Mars?

Why is everyone so excited about these dusty Mars rocks?

This week’s big news was the announcement of evidence for flowing water on Mars, based on images of what appear to be smooth river rock-type pebbles found by Curiosity. Of course that’s a big statement to make, and for good reason — identifying water, whether present or past, is one step closer to determining whether Mars was ever a suitable place for life to develop. Yet here we are, not even two months into the mission and Curiosity is already sending us solid clues that Mars was once a much wetter place than it is now.

JPL released a video today providing a brief-but-informative overview of what Curiosity has discovered in Gale Crater and why it’s gotten everyone so excited.

Check it out so you’ll have something to talk about over the weekend:

MSL Long Term Planner Sanjeev Gupta reviews Curiosity’s latest discovery

Video: JPLNews. Images: NASA/JPL-Caltech

Clay Deposits Don’t Prove Existence of Ancient Martian Lakes

HiRISE image of branching features in the floor of Antoniadi Crater thought to contain clay material. (NASA/JPL/University of Arizona)

In the hunt for evidence of a warmer, wetter past on Mars, clay deposits have been viewed as good indications that stable liquid water existed on its surface for some time — perhaps even long enough to allow life to develop. But new research conducted here on Earth shows that some clays don’t necessarily need lakes of liquid water to form. Instead they can be the result of volcanic activity, which is not nearly so hospitable to life.

A research team led by Alain Meunier of the Université de Poitiers in France studied lavas containing iron and magnesium — similar to ancient clays identified on the surface of Mars — in the French Polynesian atoll of Moruroa. The team’s findings show that the same types of clay outcrops can be caused by the solidifying of water-rich magma in a volcanic environment, and don’t require Earthlike aquatic conditions at all.

The results also correlate to the deuterium-to-hydrogen (D/H) ratio within clays found in Martian meteorites.

Read: Life from Mars Could Have Polluted Earth

“To crystallize, clays need water but not necessarily liquid water,” said Alain Meunier to the Agençe France-Presse (AFP). “Consequently, they cannot be used to prove that the planet was habitable or not during its early history.”

Additionally, the clay deposits found on Mars can be several hundred meters thick, which seems to be more indicative of upwelling magma than interactions with water.

“[This] new hypothesis proposes that the minerals instead formed during brief periods of magmatic degassing, diminishing the prospects for signs of life in these settings,” wrote Brian Hynek from the Department of Geological Sciences at the University of Colorado, in response to the paper by Meunier et al. which was published in the September 9 edition of the journal Nature Geoscience.

This does not necessarily mean that all Martian clays weren’t formed in the presence of water, however. Gale Crater — where NASA’s Curiosity rover is now exploring — could very well have been the site of a Martian lake, billions of years in the past. Clays found there could have been created by water.

Read: Take a Trip to Explore Gale Crater

According to Bethany Ehlmann of the California Institute of Technology, co-author of the study, “there are particular characteristics of texture” to clays formed under different conditions, and “Gale is a different flavor of Mars.”

Perhaps Curiosity will yet discover if Gale’s original flavor was more cool and wet than hot and spicy.

Read more on New Scientist and Cosmos Magazine.

Inset image: Moruroa Atoll (NASA) 

Is Triton Hiding an Underground Ocean?

Voyager 2 mosaic of Neptune’s largest moon, Triton (NASA)

At 1,680 miles (2,700 km) across, the frigid and wrinkled Triton is Neptune’s largest moon and the seventh largest in the Solar System. It orbits the planet backwards – that is, in the opposite direction that Neptune rotates – and is the only large moon to do so, leading astronomers to believe that Triton is actually a captured Kuiper Belt Object that fell into orbit around Neptune at some point in our solar system’s nearly 4.7-billion-year history.

Briefly visited by Voyager 2 in late August 1989, Triton was found to have a curiously mottled and rather reflective surface nearly half-covered with a bumpy “cantaloupe terrain” and a crust made up of mostly water ice, wrapped around a dense core of metallic rock. But researchers from the University of Maryland are suggesting that between the ice and rock may lie a hidden ocean of water, kept liquid despite estimated temperatures of  -97°C (-143°F), making Triton yet another moon that could have a subsurface sea.

How could such a chilly world maintain an ocean of liquid water for any length of time? For one thing, the presence of ammonia inside Triton would help to significantly lower the freezing point of water, making for a very cold — not to mention nasty-tasting — subsurface ocean that refrains from freezing solid.

In addition to this, Triton may have a source of internal heat — if not several. When Triton was first captured by Neptune’s gravity its orbit would have initially been highly elliptical, subjecting the new moon to intense tidal flexing that would have generated quite a bit of heat due to friction (not unlike what happens on Jupiter’s volcanic moon Io.) Although over time Triton’s orbit has become very nearly circular around Neptune due to the energy loss caused by such tidal forces, the heat could have been enough to melt a considerable amount of water ice trapped beneath Triton’s crust.

Related: Titan’s Tides Suggest a Subsurface Sea

Another possible source of heat is the decay of radioactive isotopes, an ongoing process which can heat a planet internally for billions of years. Although not alone enough to defrost an entire ocean, combine this radiogenic heating with tidal heating and Triton could very well have enough warmth to harbor a thin, ammonia-rich ocean beneath an insulating “blanket” of frozen crust for a very long time — although eventually it too will cool and freeze solid like the rest of the moon. Whether this has already happened or still has yet to happen remains to be seen, as several unknowns are still part of the equation.

“I think it is extremely likely that a subsurface ammonia-rich ocean exists in Triton,” said Saswata Hier-Majumder at the University of Maryland’s Department of Geology, whose team’s paper was recently published in the August edition of the journal Icarus. “[Yet] there are a number of uncertainties in our knowledge of Triton’s interior and past which makes it difficult to predict with absolute certainty.”

Still, any promise of liquid water existing elsewhere in large amounts should make us take notice, as it’s within such environments that scientists believe lie our best chances of locating any extraterrestrial life. Even in the farthest reaches of the Solar System, from the planets to their moons, into the Kuiper Belt and even beyond, if there’s heat, liquid water and the right elements — all of which seem to be popping up in the most surprising of places — the stage can be set for life to take hold.

Read more about this here on Astrobiology.net.

Inset image: Voyager 2 portrait of Neptune and Triton taken on August 28, 1989. (NASA)

Why Doesn’t Earth Have More Water?

Water, water everywhere… Coleridge’s shipbound ancient mariners were plagued by a lack of water while surrounded by a sea of the stuff, and while 70% of Earth’s surface is indeed covered by water (of which 96% is salt water, hence not a drop to drink) there’s really not all that much — not when compared to the entire mass of the planet. Less than 1% of Earth is water, which seems odd to scientists because, based on conventional models of how the Solar System formed, there should have been a lot more water available in Earth’s neck of the woods when it was coming together. So the question has been floating around: why is Earth so dry?

According to a new study from the Space Telescope Science Institute in Baltimore, MD, the answer may lie in the snow.

The snow line, to be exact. The region within a planetary system beyond which temperatures are cold enough for water ice to exist, the snow line in our solar system is currently located in the middle of the main asteroid belt, between the orbits of Mars and Jupiter. Based on conventional models of how the Solar System developed, this boundary used to be closer in to the Sun, 4.5 billion years ago. But if that were indeed the case, then Earth should have accumulated much more ice (and therefore water) as it was forming, becoming a true “water world” with a water mass up to 40 percent… instead of a mere one.

As we can see today, that wasn’t the case.

Planets such as Uranus and Neptune that formed beyond the snow line are composed of tens of percents of water. But Earth doesn’t have much water, and that has always been a puzzle.”

– Rebecca Martin, Space Telescope Science Institute 

A study led astrophysicists Rebecca Martin and Mario Livio of the Space Telescope Science Institute took another look at how the snow line in our solar system must have evolved, and found that, in their models, Earth was never inside the line. Instead it stayed within a warmer, drier region inside of the snow line, and away from the ice.

“Unlike the standard accretion-disk model, the snow line in our analysis never migrates inside Earth’s orbit,” Livio said. “Instead, it remains farther from the Sun than the orbit of Earth, which explains why our Earth is a dry planet. In fact, our model predicts that the other innermost planets, Mercury, Venus, and Mars, are also relatively dry. ”

Read: Rethinking the Source of Earth’s Water

The standard model states that in the early days of a protoplanetary disk’s formation ionized material within it gradually falls toward the star, drawing the icy, turbulent snow line region inward. But this model depends upon the energy of an extremely hot star fully ionizing the disk — energy that a young star, like our Sun was, just didn’t have.

“We said, wait a second, disks around young stars are not fully ionized,” Livio said. “They’re not standard disks because there just isn’t enough heat and radiation to ionize the disk.”


“Astrophysicists have known for quite a while that disks around young stellar objects are NOT standard accretion disks (namely, ones that are ionized and turbulent throughout),” added Dr. Livio in an email to Universe Today. “Disk models with dead zones have been constructed by many people  for many years. For some reason, however, calculations of the evolution of the snow line largely continued to use the standard disk models.”

Without fully ionized disk, the material is not drawn inward. Instead it orbits the star, condensing gas and dust into a “dead zone”  that blocks outlying material from coming any closer. Gravity compresses the dead zone material, which heats up and dries out any ices that exist immediately outside of it. Based on the team’s research it was in this dry region that Earth formed.

The rest, as they say, is water under the bridge.

The team’s results have been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

Read the release on the Hubble news site here, and see the full paper here.

Lead image: Earth as seen by MESSENGER spacecraft before it left for Mercury in 2004. NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. Disk model image: NASA, ESA, and A. Feild (STScI). Earth water volume image:  Howard Perlman, USGS; globe illustration by Jack Cook, Woods Hole Oceanographic Institution (©); Adam Nieman.

Water Balloons in Space

As part of his ongoing (and always entertaining) “Science Off the Sphere” series, Expedition 31 flight engineer Don Pettit experiments in orbit with a classic bit of summertime fun: water balloons.

Captured in real-time and slow-motion, we get to see how water behaves when suddenly freed from the restraints of an inflated latex balloon… and gravity. With Don NASA doesn’t only get a flight engineer, it gets its very own Mr. Wizard in space — check it out!

Titan’s Tides Suggest a Subsurface Sea

Saturn’s hazy Titan is now on the short list of moons that likely harbor a subsurface ocean of water, based on new findings from NASA’s Cassini spacecraft.

As Titan travels around Saturn during its 16-day elliptical orbits, it gets rhythmically squeezed by the gravitational pull of the giant planet — an effect known as tidal flexing (see video below.) If the moon were mostly composed of rock, the flexing would be in the neighborhood of around 3 feet (1 meter.) But based on measurements taken by the Cassini spacecraft, which has been orbiting Saturn since 2004, Titan exhibits much more intense flexing — ten times more, in fact, as much as 30 feet (10 meters) — indicating that it’s not entirely solid at all.

Instead, Cassini scientists estimate that there’s a moon-wide ocean of liquid water beneath the frozen crust of Titan, possibly sandwiched between layers of ice or rock.

“Short of being able to drill on Titan’s surface, the gravity measurements provide the best data we have of Titan’s internal structure.”

– Sami Asmar, Cassini team member at JPL

“Cassini’s detection of large tides on Titan leads to the almost inescapable conclusion that there is a hidden ocean at depth,” said Luciano Iess, the paper’s lead author and a Cassini team member at the Sapienza University of Rome, Italy. “The search for water is an important goal in solar system exploration, and now we’ve spotted another place where it is abundant.”

Although liquid water is a necessity for the development of life, the presence of it alone does not guarantee that alien organisms are swimming around in a Titanic underground ocean. It’s thought that water must be in contact with rock in order to create the necessary building blocks of life, and as yet it’s not known what situations may exist around Titan’s inner sea. But the presence of such an ocean — possibly containing trace amounts of ammonia — would help explain how methane gets replenished into the moon’s thick atmosphere.

“The presence of a liquid water layer in Titan is important because we want to understand how methane is stored in Titan’s interior and how it may outgas to the surface,” said Jonathan Lunine, a Cassini team member at Cornell University, Ithaca, N.Y. “This is important because everything that is unique about Titan derives from the presence of abundant methane, yet the methane in the atmosphere is unstable and will be destroyed on geologically short timescales.”

The team’s paper appears in today’s edition of the journal Science. Read more on the Cassini mission site here.

Top image: artist’s concept showing a possible scenario for the internal structure of Titan. (A. Tavani). Side image: An RGB-composite color image of Titan and Dione in front of Saturn’s face and rings, made from Cassini images acquired on May 21, 2011. (NASA/JPL/SSI. Composite by J. Major.)