MARS HiRise Map: Signs of Ancient Mars Lakes and Quakes

Long ago, in the largest canyon system in our solar system, vibrations from "marsquakes" shook soft sediments that had accumulated in Martian lakes.

The shaken sediments formed features that now appear as a series of low hills apparent in a geological map based on NASA images.

The map was released by the U.S. Geological Survey (USGS).

This map of the western Candor Chasma canyon within Mars' Valles Marineris is the highest-resolution Martian geological map ever relased by USGS.

It is derived from images taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter (MRO), which reveal details smaller than a desk.

"This new map shows that at the time these sediments were deposited, a part of west Candor Chasma, specifically Condor Colles, contained numerous shallow, spring-fed lakes," said map author Chris Okubo of the USGS Astrogeology Science Center, Flagstaff, Arizona.


"These lakes helped to trap wind-blown sand and dust, which accumulated over time and formed the extensive sedimentary deposits we see today."

The wet sediments experienced seismic shaking in "marsquakes" related to movement along several large geological faults in the area. A series of low hills resulted.

Valles Marineris is more than 2,500 miles (4,000 kilometers) long. The conditions under which sedimentary deposits in it formed have been an open issue for decades.

Possibilities proposed have included accumulation in lakebeds, volcanic eruptions under glaciers within the canyons, and acculation of wind-blown sand and dust.

The map is available for download here. Additional information about the map is available here.

CASTRO Simulations reveal an unusual death for ancient stars

This image is a slice through the interior of a supermassive star of 55,500 solar masses along the axis of symmetry. 

It shows the inner helium core in which nuclear burning is converting helium to oxygen, powering various fluid instabilities (swirling lines). 

This "snapshot" from a CASTRO simulation shows one moment a day after the onset of the explosion, when the radius of the outer circle would be slightly larger than that of the orbit of the Earth around the sun. 

Visualizations were done in VisIT. 

Credit: Ken Chen, University of California at Santa Cruz

Certain primordial stars, those 55,000 and 56,000 times the mass of our Sun, or solar masses, may have died unusually.

In death, these objects, among the Universe's first-generation of stars, would have exploded as supernovae and burned completely, leaving no remnant black hole behind.

Astrophysicists at the University of California, Santa Cruz (UCSC) and the University of Minnesota came to this conclusion after running a number of supercomputer simulations at the US Department of Energy's (DOE's) National Energy Research Scientific Computing Center (NERSC) and Minnesota Supercomputing Institute at the University of Minnesota.

They relied extensively on CASTRO, a compressible astrophysics code developed at DOE's Lawrence Berkeley National Laboratory's (Berkeley Lab's) Computational Research Division (CRD).

Their findings were recently published in Astrophysical Journal (ApJ).

First-generation stars are especially interesting because they produced the first heavy elements, or chemical elements other than hydrogen and helium.

In death, they sent their chemical creations into outer space, paving the way for subsequent generations of stars, solar systems and galaxies.

With a greater understanding of how these first stars died, scientists hope to glean some insights about how the Universe, as we know it today, came to be.

"We found that there is a narrow window where supermassive stars could explode completely instead of becoming a supermassive black hole, no one has ever found this mechanism before," says Ke-Jung Chen, a postdoctoral researcher at UCSC and lead author of the ApJ paper.

"Without NERSC resources, it would have taken us a lot longer to reach this result."

"From a user perspective, the facility is run very efficiently and it is an extremely convenient place to do science."

More information: Astrophysical Journal, iopscience.iop.org/0004-637X/790/2/162

US Researchers to use exosuit to explore ancient Greek Antikythera wreck

Marine archeologists with the American Museum of Natural History are planning to explore the ancient Greek Antikythera wreck in the Agean Sea, using an exosuit developed by Nuytco Research, originally for use in helping workers in New York's water treatment facilities.

The iron-man looking exosuit allows a diver to descend to 1000 feet for hours at a time without need for decompressing upon returning to the surface.

The Antikythera was discovered by divers in 1900, attempts to explore the wreck resulted in recovery of many artifacts, mostly famously, one that is known as the Antikythera mechanism, now referred to as the world's oldest computer, but it also led to injury and death due to the extreme depth (120 meters).

Subsequent attempts more recently have led to more discoveries, but time constraints have prevented a thorough study of the wreck.

Wearing the exosuit, the researchers hope will not only allow for mapping the wreck, but for discovery of more artifacts, some perhaps as interesting as the Antikythera mechanism.

The suit, which is essentially a body submarine, allows for both arm and leg movements, courtesy of multiple patented rotary joints.

It also has 1.6 horsepower thrusters that are activated by the "pilot" via pads inside the boots.

It's made of mostly aluminum, and weighs 530 pounds. The hands are claw-like, which has meant many hours of training in pools for the research team.

The suit also has external LED lights and cameras, an oxygen replenishment system and a tether to the surface with a fiber optic gigabit Ethernet that allows for two-way communications, a live video feed, and monitoring of the suit and its wearer.

In the event of an emergency, the suit has backup batteries and systems to maintain life support, if necessary, the four man crew up top can take over control of the suit to bring the diver out of harm's way.

The team has scheduled a test run of the suit this summer at a site called the Canyons off the coast of Rhode Island. If all goes well, plans for exploring the Antikythera wreck can proceed, paving the way for a whole new way to explore undersea wrecks from virtually any era.

Ancient Bow City crater points to massive meteorite strike

This is a map showing the structure and contour of the Bow City crater. Colour variation shows meters above sea level. 

Credit: Alberta Geographic Survey /University of Alberta

The discovery of an ancient ring-like structure in southern Alberta suggests the area was struck by a meteorite large enough to leave an eight-kilometre-wide crater, producing an explosion strong enough to destroy present-day Calgary, say researchers from the Alberta Geographic Survey and University of Alberta.

Doug Schmitt

The first hints about the impact site near the southern Alberta hamlet of Bow City were discovered by a geologist with the Alberta Geographic Survey and studied by a University of Alberta team led by Doug Schmitt, Canada Research Chair in Rock Physics.

Time and glaciers have buried and eroded much of the evidence, making it impossible at this point to say with full certainty the ring-like structure was caused by a meteorite impact, but that's what seismic and geological evidence strongly suggests, said Schmitt, a professor in the Faculty of Science and co-author of a new paper about the discovery.

"We know that the impact occurred within the last 70 million years, and in that time about 1.5 km of sediment has been eroded. That makes it really hard to pin down and actually date the impact."

Erosion has worn away all but the "roots" of the crater, leaving a semicircular depression eight kilometres across with a central peak.

Schmitt says that when it formed, the crater likely reached a depth of 1.6 to 2.4 km, the kind of impact his graduate student Wei Xie calculated would have had devastating consequences for life in the area.

"An impact of this magnitude would kill everything for quite a distance," he said. "If it happened today, Calgary (200 km to the northwest) would be completely fried and in Edmonton (500 km northwest), every window would have been blown out."

"Something of that size, throwing that much debris in the air, potentially would have global consequences; there could have been ramifications for decades."

The impact site was first discovered in 2009 by geologist Paul Glombick, who at the time was working on a geological map of the area for the Alberta Geographic Survey.

Glombick relied on existing geophysical log data from the oil and gas industry when he discovered a bowl-shaped structure.

The Alberta Geological Survey contacted the U of A and Schmitt to explore further, peeking into the earth by analyzing seismic data donated by industry.

Schmitt's student, Todd Brown, later confirmed a crater-like structure.

The research team's paper about the discovery was published in the journal Meteoritics & Planetary Science in an early online release.

NASA MESSENGER: Ancient volcanic explosions shed light on Mercury's origins

Two pyroclastic vents on the floor of Mercury’s Kipling crater, top, would likely not have survived the impact; they are more recent. 

The false colour image of the same spot, bottom, marks pyroclastic material as brownish red.

The surface of Mercury crackled with volcanic explosions for extended periods of the planet's history, according to a new analysis led by researchers at Brown University.

The findings are surprising considering Mercury wasn't supposed to have explosive volcanism in the first place, and they could have implications for understanding how Mercury formed.

On Earth, volcanic explosions like the one that tore the lid off Mount St. Helens happen because our planet's interior is rich in volatiles - water, carbon dioxide and other compounds with relatively low boiling points.

As lava rises from the depths toward the surface, volatiles dissolved within it change phase from liquid to gas, expanding in the process.

The pressure of that expansion can cause the crust above to burst like an over-inflated balloon.

Mercury, however, was long thought to be bone dry when it comes to volatiles, and without volatiles there can't be explosive volcanism.

But that view started to change in 2008, after NASA's MESSENGER spacecraft made its first flybys of Mercury.

Those glimpses of the surface revealed deposits of pyroclastic ash - the telltale signs of volcanic explosions - peppering the planet's surface.

It was a clue that at some point in its history Mercury's interior wasn't as bereft of volatiles as had been assumed.

What wasn't clear from those initial flybys was the timeframe over which those explosions occurred.

Did Mercury's volatiles escape in a flurry of explosions early in the planet's history or has Mercury held on to its volatiles over a much longer period?

This latest work, available in online early view at the Journal of Geophysical Research: Planets, suggests the latter.

Hubble UDS: Ancient Granny galaxies discovered in the early universe

UDS (UKIDDS Ultra Deep Survey) astronomical field, with four of the 15 mature galaxies, based on the infrared light of NASA's Hubble Space Telescope. 

The galaxies exhibit the typical red colours of mature galaxies. 

Most of the other galaxies in the image are much closer. 

Credit: Caroline Straatman.

An international team of astronomers have discovered the most distant examples of galaxies that were already mature and massive – not just young, star-forming galaxies in the nursery-room of the early Universe but also old, 'retired' ones – 'granny galaxies'.

Lee Spitler

A new paper, published in the Astrophysical Journal Letters by researchers from Macquarie University, the Australian Astronomical Observatory (AAO) and Swinburne University of Technology raises new questions about the early Universe, and what forced these mature galaxies to grow up so quickly.

"Scientists have known about large numbers of young galaxies in the early universe actively forming new stars," says co-author Dr Lee Spitler.

Caroline Straatman

"The ones we've found have already gone through this phase: they have actually taken an early retirement from star-formation, when the universe was only 12% of its current age.

Because they grew up so quickly, it's likely they underwent an explosive period of new star formation – a brief, so called starburst phase – then retired."

Dr Lee Spitler, a joint appointment between Macquarie University and the AAO, joined the team in using deep images at near-infrared wavelengths to search for galaxies in the early universe with red colors.

The characteristic red colours indicate the presence of old stars and a lack of active star formation.

Karl Glazebrook

"These distant and early massive galaxies are one of the Holy Grails of astronomy," Professor Karl Glazebrook, Director of the Centre for Astrophysics and Supercomputing at Swinburne University of Technology, said.

"Fifteen years ago they were predicted not to even exist within the cosmological model favoured at the time."

"In 2004 I wrote a paper on the discovery of such galaxies existing only three billion years after the Big Bang."

"Now, with improved technology we are pushing back to only 1.6 billion years, which is truly exciting."

FourStar camera on the Magellan Baade

The galaxies were discovered after 40 nights of observing with the FourStar camera on the Magellan Baade Telescope in Chile and combined with data from Hubble's Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and the Great Observatories Origins Deep Survey (GOODS).

Using special filters to produce images that are sensitive to narrow slices of the near-infrared spectrum, the team were able to measure accurate distances to thousands of distant galaxies at a time, providing a 3-D map of the early universe.

More information: "A substantial population of massive quiescent galaxies at z~4 from ZFOURGE," Astrophysical Journal Letters, 18 February 2014, C. Straatman, I. Labbé, L. Spitler, R. Allen, et al: DOI: 10.1088/2041-8205/783/1/L14

Supernova Legacy Survey: Powerful ancient explosions explain new class of supernovae

A small portion of one of the fields from the Supernova Legacy Survey showing SNLS-06D4eu and its host galaxy (arrow). 

The supernova and its host galaxy are so far away that both are a tiny point of light that cannot be clearly differentiated in this image. 

The large, bright objects with spikes are stars in our own galaxy. 

Every other point of light is a distant galaxy. 

Credit: UCSB

Astronomers affiliated with the Supernova Legacy Survey (SNLS) have discovered two of the brightest and most distant supernovae ever recorded, 10 billion light-years away and a hundred times more luminous than a normal supernova. Their findings appear in the Dec. 20 issue of the Astrophysical Journal.

These newly discovered supernovae are especially puzzling because the mechanism that powers most of them—the collapse of a giant star to a black hole or normal neutron star—cannot explain their extreme luminosity.

Discovered in 2006 and 2007, the supernovae were so unusual that astronomers initially could not figure out what they were or even determine their distances from Earth.

"At first, we had no idea what these things were, even whether they were supernovae or whether they were in our galaxy or a distant one," said lead author D. Andrew Howell, a staff scientist at Las Cumbres Observatory Global Telescope Network (LCOGT) and adjunct faculty at UC Santa Barbara.

"I showed the observations at a conference, and everyone was baffled. Nobody guessed they were distant supernovae because it would have made the energies mind-bogglingly large. We thought it was impossible."

One of the newly discovered supernovae, named SNLS-06D4eu, is the most distant and possibly the most luminous member of an emerging class of explosions called superluminous supernovae.

These new discoveries belong to a special subclass of superluminous supernovae that have no hydrogen.

The new study finds that the supernovae are likely powered by the creation of a magnetar, an extraordinarily magnetized neutron star spinning hundreds of times per second.

Magnetars have the mass of the sun packed into a star the size of a city and have magnetic fields a hundred trillion times that of the Earth.

While a handful of these superluminous supernovae have been seen since they were first announced in 2009, and the creation of a magnetar had been postulated as a possible energy source, the work of Howell and his colleagues is the first to match detailed observations to models of what such an explosion might look like.

Co-author Daniel Kasen from UC Berkeley and Lawrence Berkeley National Lab created models of the supernova that explained the data as the explosion of a star only a few times the size of the sun and rich in carbon and oxygen.

The star likely was initially much bigger but apparently shed its outer layers long before exploding, leaving only a smallish, naked core.

More information: dx.doi.org/10.1088/0004-637X/779/2/98

NASA Curiosity Rover: Ancient Mars Lake Could Have Supported Life

Mastcam mosaic of the Yellowknife Bay formation. This is a view from the base of an exposed section up through Sheepbed, Gillespie Lake, and basal Glenelg members. 

Locations of drill holes and Alpha Particle X-Ray Spectrometer (A PXS) measurements are shown. Image released Dec. 9, 2013. Credit: Science/AAAS



The lake could have potentially supported a class of microbes called chemolithoautotrophs, which obtain energy by breaking down rocks and minerals.

Here on Earth, chemolithoautotrophs are commonly found in habitats beyond the reach of sunlight, such as caves and hydrothermal vents on the ocean floor.

NASA Mars Curiosity Rover: Ancient fresh water lake on Mars could have sustained life

Mars Hand Lens Imager (MAHLI) image of a brushed, gray bedrock outcrop of Sheepbed mudstone near the Cumberland drill hole. 

Protrusion of nodules and minibowls results from eolian scouring of rock surface, creating wind-tails that trend NE-SW. 

Preference for steep faces of wind-tails on NE side suggests long-term averaged paleowind direction from NE to SW. 

For more information, please see Figure 3 in the manuscript by Farley et al. Credit: Science/AAAS

Scientists have found evidence that there was once an ancient lake on Mars that may have been able to support life, in research published today in the journal Science.

A team of researchers from NASA's Mars Science Laboratory (MSL) Curiosity rover mission, which includes a researcher from Imperial College London, have analysed a set of sedimentary rock outcrops at a site named Yellowknife Bay in Gale Crater, near the Martian equator.

These mudstones have revealed that Gale Crater, a 150 km wide impact basin with a mountain at its centre, sustained at least one lake around 3.6 billion years ago.

The scientists believe that the lake may have lasted for tens if not hundreds of thousands of years.

The team's analysis showed that the lake was calm and likely had fresh water, containing key biological elements such as carbon, hydrogen, oxygen, nitrogen and sulphur.

Such a lake would provide perfect conditions for simple microbial life such as chemolithoautotrophs to thrive in.

On Earth, chemolithoautotrophs are commonly found in caves and around hydrothermal vents. The microbes break down rocks and minerals for energy.

Mudstones generally form in calm conditions. They are created by very fine sediment grains settling layer-by-layer on each other, in still water.

Sedimentary rocks of the Yellowknife Bay formation. 

For more information on each individual image, please see Figure 5 in the manuscript by Grotzinger et al.

Credit: Science/AAAS

Professor Sanjeev Gupta, a member of the MSL mission from the Department of Earth Science and Engineering at Imperial College London and a co-author on the papers, says: "It is important to note that we have not found signs of ancient life on Mars."

"What we have found is that Gale Crater was able to sustain a lake on its surface at least once in its ancient past that may have been favourable for microbial life, billions of years ago. This is a huge positive step for the exploration of Mars."

"It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake's calm waters, converting a rich array of elements into energy."

"The next phase of the mission, where we will be exploring more rocky outcrops on the crater's surface, could hold the key whether life did exist on the red planet."

In previous studies, Professor Gupta and the MSL team have found evidence of water on Mars' surface in other rocks such as conglomerates.

However, the new research provides the strongest evidence yet that Mars could have been habitable enough for life to take hold.

For all papers: mars.jpl.nasa.gov/msl/mission/science/researchpapers/ and gps.caltech.edu/~grotz/Publications/MSL%20Publications.html

NASA WISE reveals the Milky Way's ancient brown dwarf population

A brown dwarf from the thick-disk or halo is shown. 

Although astronomers observe these objects as they pass near to the solar system, they spend much of their time away from the busiest part of the Galaxy, and the Milky Way's disk can be seen in the background. 

Credit: John Pinfield

A team of astronomers led by Dr David Pinfield at the University of Hertfordshire have discovered two of the oldest brown dwarfs in the Galaxy.

These ancient objects are moving at speeds of 100-200 kilometres per second, much faster than normal stars and other brown dwarfs and are thought to have formed when the Galaxy was very young, more than 10 billion years ago.

Intriguingly the scientists believe they could be part of a vast and previously unseen population of objects. The researchers publish their results in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society.

Brown dwarfs are star-like objects but are much less massive (with less than 7% of the Sun's mass), and do not generate internal heat through nuclear fusion like stars.

Because of this brown dwarfs simply cool and fade with time and very old brown dwarfs become very cool indeed - the new discoveries have temperatures of 250-600 degrees Celsius, much cooler than stars (in comparison the Sun has a surface temperature of 5600 degrees Celsius).

Pinfield's team identified the new objects in the survey made by the Wide-field Infrared Survey Explorer (WISE), a NASA observatory that scanned the mid-infrared sky from orbit in 2010 and 2011.

The object names are WISE 0013+0634 and WISE 0833+0052, and they lie in the Pisces and Hydra constellations respectively.

Additional measurements confirming the nature of the objects came from large ground-based telescopes (Magellan, Gemini, VISTA and UKIRT).

The infrared sky is full of faint red sources, including reddened stars, faint background galaxies (large distances from our own Milky Way) and nebulous gas and dust.

Identifying cool brown dwarfs in amongst this messy mixture is akin to finding needles in a haystack. But Pinfield's team developed a new method that takes advantage of the way in which WISE scans the sky multiple times.

This allowed them to identify cool brown dwarfs that were fainter than other searches had revealed.

The team of scientists then studied the infrared light emitted from these objects, which are unusual compared to typical slower moving brown dwarfs.

The spectral signatures of their light reflects their ancient atmospheres, which are almost entirely made up of hydrogen rather than having the more abundant heavier elements seen in younger stars.

Pinfield comments on their venerable ages and high speeds, "Unlike in other walks of life, the Galaxy's oldest members move much faster than its younger population".

More information: "A deep WISE search for very late type objects and the discovery of two halo/thick-disk T dwarfs: WISE 0013+0634 and WISE 0833+0052", D. J. Pinfield et al, Monthly Notices of the Royal Astronomical Society, in press. A pre-publication version of the paper is available on arXiv: arxiv.org/abs/1308.0495

NASA MAVEN: 'Tour' ancient, wet Mars in YouTube video

NASA's Goddard Space Flight Center has release a YouTube video it says shows how Mars may have looked 4 billion years ago.

When the Red Planet was young, it appears to have had a thick atmosphere that was warm enough to support oceans of liquid water -- a critical ingredient for life -- and the YouTube video shows how the planet could have appeared at the time, the space agency said Wednesday.

Beginning with a flyover of a martian lake, rapidly moving clouds suggest the passage of time and the shift from a warm and wet to a cold and dry climate.

As millions of years fly by the lakes dry up, while the atmosphere gradually transitions from Earth-like blue skies to the dusty pink and tan hues seen on Mars today.

NASA's YouTube "tour" of Mars comes as it prepares to launch its MAVEN spacecraft that will study the planet's atmosphere.

The launch is set for Nov. 18 from Florida's Cape Canaveral Air Force Station.

Pluto satellites' orbital ballet may hint of long-ago collisions

A best-fit colour image/map of Pluto generated with the Hubble Space Telescope and advanced computers. Image: NASA

A large impact 4 billion years ago may account for the puzzling orbital configuration among Pluto's five known satellites, according to a new model developed by planetary scientists from Southwest Research Institute (SwRI).

Starting with Charon, Pluto's nearest and largest moon, each of the successively more distant—and much smaller—moons orbits Pluto according to a steadily increasing factor of Charon's own orbital period.

The small satellites, Styx, Nix, Kereberos and Hydra, have orbital periods that are almost exactly 3, 4, 5 and 6 times longer than Charon's.

Harold "Hal" Levison

"Their distance from Pluto and the orbital arrangement of the satellites has been a challenge for theories of the small satellites' formation," said lead investigator Dr. Harold "Hal" Levison, an Institute scientist in SwRI's Planetary Science Directorate at Boulder, Colo.

Models for the formation of Charon leave plenty of small satellites, but all of them are much closer to Pluto than the current system that we see today," said Levison.

A major problem has been understanding how to move these satellites outward, but not lose them from the Pluto-Charon system or have them crash into Charon.

He said, "This configuration suggests that we have been missing some important mechanism to transport material around in this system."

The SwRI study, funded by a grant from NASA's Outer Planetary Research program and Lunar Science Institute, considered the earliest and most dynamic epoch of the Pluto/Charon system.

It is thought that Charon was formed by a large impact during a period in solar system history when such collisions were dramatically more frequent.

Pluto's moon Charon

Any initially surviving satellites would likely be destroyed in collisions, but these shattered moons wouldn't be lost; rather, their remains would stay in the Pluto/Charon system and become the starting point for building new satellites.

Thus there would have been many generations of satellite systems over the history of Pluto and Charon.

In modeling the destruction of the satellites, the SwRI study found that there may be a method for moving them, or their building blocks, outward, due to the competing effects of Charon's gravitational kicks and collisions among the debris of the disrupted satellites.

Charon is the largest satellite of any planet or dwarf-planet, weighing in at 1/10 the mass of Pluto (the Moon is just 1/81 the mass of Earth), and so it could rapidly slingshot the small satellites outward if they were to approach too closely.

Kevin Walsh

Meanwhile, collisions among small satellites can change orbits to keep things away from Charon. When combined, this leads to a series of satellites colliding, breaking to pieces, moving outward and then rebuilding.

"The implications for this result are that the current small satellites are the last generation of many previous generations of satellites," said Dr. Kevin Walsh, another investigator and a research scientist in SwRI's Planetary Science Directorate at Boulder, Colo.

"They were probably first formed around 4 billion years ago, and after an eventful million years of breaking and rebuilding, have survived in their current configuration ever since."

Mars crater may actually be ancient supervolcano

Seen above, for the basin and surrounding area, higher elevations (reds and yellows) and lower elevations (blues and grays) are indicated. Credit: NASA/JPL/GSFC

A research project led by Joseph R. Michalski, Senior Scientist at the Planetary Science Institute, has identified what could be a supervolcano on Mars – the first discovery of its kind.

In a paper published Oct. 3 in the journal Nature, Michalski and co-author Jacob E. Bleacher of NASA Goddard Space Flight Center describe a new type of volcanic construction on Mars that until now has gone unrecognized.

The volcano in question, a vast circular basin on the face of the Red Planet, previously had been classified as an impact crater.

Researchers now suggest the basin is actually the remains of an ancient supervolcano eruption.

Their assessment is based on images and topographic data from NASA's Mars Odyssey, Mars Global Surveyor and Mars Reconnaissance Orbiter (MRO) spacecraft, as well as the European Space Agency's Mars Express orbiter.

In the Nature paper Michalski and Bleacher lay out their case that the basin, recently named Eden Patera, is a volcanic caldera. Because a caldera is a depression, it can look like a crater formed by an impact, rather than a volcano.

"On Mars, young volcanoes have a very distinctive appearance that allows us to identify them," Michalski said. "The long-standing question has been what ancient volcanoes on Mars look like. Perhaps they look like this one."

Above, the dark color indicates younger material draped across the Eden Patera depression. 

Credit: ESA

The researchers also suggest a large body of magma loaded with dissolved gas (similar to the carbonation in soda) rose through thin crust to the surface quickly.

Like a bottle of soda that has been shaken, this supervolcano would have blown its contents far and wide if the top came off suddenly.

"This highly explosive type of eruption is a game-changer, spewing many times more ash and other material than typical, younger Martian volcanoes," Bleacher said.

"During these types of eruptions on Earth, the debris may spread so far through the atmosphere and remain so long that it alters the global temperature for years."

After the material is expelled from the eruption, the depression that is left can collapse even further, causing the ground around it to sink.

Eruptions like these happened in ages past at what is now Yellowstone National Park in the western United States, Lake Toba in Indonesia and Lake Taupo in New Zealand.

More information: www.nature.com/nature/journal/v502/n7469/full/nature12482.html

NASA Curiosity Rover Finds New Evidence That Ancient Mars Was Habitable

The pale rock in the upper center of this image, about the size of a human forearm, includes a target called "Esperance," which was inspected by NASA's Mars Exploration Rover Opportunity.

This image is a composite of three exposures taken by Opportunity's panoramic camera during the 3,262nd Martian day, or sol, of the rover's work on Mars (March 28, 2013).

CREDIT: NASA/JPL-Caltech/Cornell/Arizona State Univ.

NASA's Mars rover Opportunity has made perhaps the biggest discovery of its nearly 10-year career, finding evidence that life may have been able to get a foothold on the Red Planet long ago.

The Opportunity rover spotted clay minerals in an ancient rock on the rim of Mars' Endeavour Crater, suggesting that benign, neutral-pH water once flowed through the area, scientists said.

"This is water you could drink," Opportunity principal investigator Steve Squyres of Cornell University told reporters today (June 7), explaining why the rock, dubbed "Esperance," stands out from other water-soaked stones the rover has studied.

"This is water that was probably much more favorable in its chemistry, in its pH, in its level of acidity, for things like prebiotic chemistry — the kind of chemistry that could lead to the origin of life," Squyres added.

NASA MSL: Ancient streambed found on surface of Mars

This set of images compares the Link outcrop of rocks on Mars (left) with similar rocks seen on Earth (right). Credit: NASA

Rounded pebbles on the surface of Mars indicate that a stream once flowed on the red planet, according to a new study by a team of scientists from NASA's Curiosity rover mission, including a University of California, Davis, geologist.

The study will be published in the May 31 issue of the journal Science.

Rounded pebbles of this size are known to form only when transported through water over long distances.

They were discovered between the north rim of the planet's Gale Crater and the base of Mount Sharp, a mountain inside the crater.

The finding represents the first on-site evidence of sustained water flows on the Mars landscape, and supports prospects that the planet could once have been able to host life.

As a co-investigator for NASA's Mars Science Laboratory team, UC Davis geologist and study co-author Dawn Sumner played a key role in choosing Gale Crater as the landing site for Curiosity.

Finding the rounded pebbles, which were deposited more than 2 billion years ago, was a matter of landing in the right place, she said.

"The main reason we chose Gale Crater as a landing site was to look at the layered rocks at the base of Mount Sharp, about five miles away," she said.

"We knew there was an alluvial fan in the landing area, a cone-shaped deposit of sediment that requires flowing water to form. These sorts of pebbles are likely because of that environment. So while we didn't choose Gale Crater for this purpose, we were hoping to find something like this."

The finding comes from Curiosity's exploration of the Mars surface during its first 100 sols (102.7 days on Earth), or Martian days.

During that time, the rover traveled about a quarter mile from its landing site, examining multiple outcrops of pebble-rich slabs.

Curiosity took high-resolution images of these pebbles at three locations known as Goulburn, Link and Hottah.

The grain size, roundness and other characteristics of the pebbles led the researchers to conclude they had been transported by water.

Sumner said the discovery involves some of the most basic principles of geology.

The study area, which has been named 'Hottah', is by all accounts the remains of sediments from the bottom of an ancient stream, which had a relatively strong current. Credit: Malin Space Science Systems

"On the first day of my sedimentary class, I have the students measure grain size and the rounding," Sumner said. "It's simple, and it's important."

Sumner's work in South Africa and Australia studying signs of past microbial life in rocks and her work on living microbial communities in Antarctica helped land her the spot on the Mars Science Laboratory team.

NASA recognized her skills could be critical to the mission's goal: to determine whether there ever could have been life on Mars.

As part of the MSL team, Sumner helped coordinate the first scientific interpretations of what was seen during Curiosity's first few days on Mars, helps direct the rover, via computer, to shoot photographs of the planet, and continues to work on the mission from UC Davis.

Remnants of Ancient Supernova Explosion found in Magnetotactic Bacteria

Back in 2004, German scientists discovered traces of supernova ejecta that had been deposited in the deep-sea ferromanganese crust of the pacific ocean. 

They dated the supernova event to 2.8 million years ago (Mya), using estimates from the decay of iron-60 radioisotope.

They were also able to estimate the distance of the supernova event to 10 parsecs (pc) from our sun, based on the amount of iron-60 deposited.

Prof Shawn Bishop

At the April 14th meeting of the American Physical Society (APS), another German scientist, Shawn Bishop, reported finding traces of iron-60 of supernova origin in the fossilized remains of a common bacteria.

By accurately dating the sediment cores in which the samples were found, Bishop appears to have discovered the first biological signature of an ancient supernova event, and may even be able to link it to a specific exploding star.

Bishop analyzed sample cores from strata roughly 100,000 years apart within deposits from 1.7 to 3.3 Mya. Iron-60 is not a product of any processes occurring here on earth, so any supply of it can be assumed to from a non-terrestrial source.

Bishop was able to extract out all the iron-60 of biological origin, and quantify it with a mass spectrometer.

The amounts found were small, but they were enough to reliably date the sample to a period around 2.2 Mya.

Other researchers, peripheral to the project, were then able to suggest a possible candidate star that dates to this period may lie in the Scorpius-Centaurus stellar association, roughly 130 pcs (424 light-years) from the sun.

More information: Abstract: X8.00002 : Search for Supernova 60Fe in the Earth's Fossil Record, Bulletin of the American Physical Society, meetings.aps.org/Meeting/APR13/Event/192798

Ancient Mega-Flood on Mars Revealed in 3D

The Mars map shows the location of the nearly 1,000-kilometer Marte Vallis channel system on Mars created during an ancient mega-flood. 

Marte Vallis is filled with lava obscuring the source and morphology of the channels. Image released March 7, 2013.

CREDIT: NASA/MOLA Team/Smithsonian Institution

Radar scans of Mars have revealed the first 3D look at water-carved channels buried beneath the Red Planet's surface, researchers say.

The discovery shows that a major underground channel generated by an ancient mega-flood is twice as deep as thought, and sheds light on how water shaped the surface of Mars, scientists added.

Mars today is cold and dry, with most of its water locked in polar ice caps, and researchers think its surface has been largely barren for the past 2.5 billion years. However, channels crisscrossing its surface hint that waters once flooded the Red Planet's surface.

The largest of the channels engraved into Mars within the past 500 million years belong to the 600-mile-long (1,000 kilometer) Marte Vallis system. Probing Marte Vallis could offer hints on a time otherwise thought of as cold and dry.

However, Marte Vallis lies in Elysium Planitia, an expanse of plains along the Martian equator. This area is the youngest volcanic region on Mars, and massive volcanism throughout the past several hundred million years has covered most of its surface with lava, burying evidence of its recent history, including the source and most of the length of Marte Vallis.

Now, using the shallow radar onboard the Mars Reconnaissance Orbiter, scientists have scanned beneath the surface of Elysium Planitia. Their data helped generate a 3D reconstruction of Marte Vallis, revealing many details that lava flows buried long ago.

"This is the first time we've been able to see buried flood channels on a planet other than the Earth," lead study author Gareth Morgan, a geologist at the Smithsonian's National Air and Space Museum, reported.

The researchers found the channels of Marte Vallis were at least 230 feet (70 meters) deep, making them at least twice as deep as thought.

"That shows previous ideas of erosion, of how much water have gone through Marte Vallis, have been underestimated," Morgan said. "There was more significant flooding than before thought, and it's interesting to think of where this water might have come from during this relatively dry period."

This 3D visualization shows the buried Marte Vallis channels beneath the Martian surface created during an ancient mega-flood. 

Marte Vallis consists of multiple perched channels formed around streamlined islands. 

These channels feed a deeper and wider main channel. 

Note the surface has been elevated, and scaled by a factor of 1/100 for clarity, with colours representing the elevation of the buried channels. 

Image released March 7, 2013. 

CREDIT: Smithsonian Institution/NASA/JPL-Caltech/Sapienza University of Rome/MOLA Team/USGS


By mapping the buried channels, researchers discovered the ancient gigantic floods that probably created Marte Vallis apparently originated deep underground from a now-buried portion of fissures known as Cerberus Fossae.

"The source of the floodwaters suggests they originated from a deep groundwater reservoir and may have been released by local tectonic or volcanic activity," Morgan said.

Marte Vallis is similar to more ancient systems of channels on Mars. The gargantuan floods that generated these channels may also have briefly radically changed the Red Planet's climate just as giant floods of Arctic water have on Earth. Learning more about Martian floods could provide information on key parts of that world's history, researchers said.

"There's also evidence of channels buried by lava or other sorts of materials in other areas on Mars, and we'd like to apply the same sort of radar studies to those," Morgan said.

The scientists detailed their findings online today (March 7) in the journal Science.

Helicoprion: Mystery of ancient Spiral-Toothed Shark clarified

An ancient spiral-toothed fish has been reconstructed from fossil evidence by scientists.

US researchers used CT scans to build a computer model of what Helicoprion looked like and how it ate.

They were also able to resolve an ongoing puzzle over whether the unique saw-like spirals were located inside or outside the mouth.

The findings show the animals were more closely related to modern chimaeras, or ratfish, than sharks.

The study is published by researchers from Idaho State University in the Royal Society journal Biology Letters.

The university's Museum of Natural History has the largest public collection of fossilised Helicoprion in the world.

The fish lived 270 million years ago but because they were largely formed from cartilage, which does not preserve well, their fossil record comprises unusual spiral structures.

Referred to as "whorls", these features have been compared to spiralling saw blades and have puzzled the scientific community for over a century.

Early theories suggested that they were actually used for defence and were located on the fish's upper or lower jaws, or even the dorsal fin.

Dental records
To solve the mystery, Dr Leif Tapanila and colleagues investigated the most complete fossil in the collection.

The fossil, discovered in Idaho, has a whorl measuring 23cm with 117 individual teeth. Unlike other specimens, the fossil also includes impressions of the cartilage structures.

The team used a high-powered CT scan, which uses X-rays to create a detailed computer image, in order to fully analyse what was inside the rock.

"When we got the images back, we could easily see that we had the upper and lower jaw of the animals, as well as the spiral of teeth," said Dr Tapanila.

"For the first time we were able to very clearly image how that spiral of teeth relates to the jaw."

The scientists found that the spiral was connected to the fish's lower jaw, in the back of the mouth.

"Imagine that... instead of having a tongue, you have this large spiral of teeth," Dr Tapanila explained.

"Only maybe a dozen teeth are poking up out of your lower jaw so you can bite."

"The rest of those teeth are stored inside and are not being used, those are your baby teeth - the teeth you had when you were younger."

Dr Tapanila said this discovery supports the argument that unlike sharks, which constantly replace their teeth, Helicoprion retained its teeth permanently.

Using the computer images, the team could build a 3D model of the jaw, to reveal how the tooth spiral worked.

"As the mouth closes, the teeth spin backwards... so they slash through the meat that they are biting into," Dr Tapanila reported.

"The teeth themselves are very narrow: nice long, pointy, triangular teeth with serrations like a steak knife.

"As the jaw is closing and the teeth are spinning past whatever it's eating, it's making a very nice clean cut."

Of the 100 fossils of Helicoprion that have been discovered, very few show broken or worn teeth.



Ancient diet
Dr Tapanila said that this evidence, combined with the "rolling and slicing" mechanism, provided clues to what the ancient fish ate.

"If this animal were eating other animals that were very hard or [had] hard armour plating or dense shells, you would expect more damage to their teeth.

"This leads us to believe that our animal was probably eating soft, squishy things like calamari. It was probably eating squid or its relatives that were swimming in the ocean at the time."

The study also highlighted the family connections of the ancient fish, categorising it with chimaeras and ratfish rather than sharks.

"One of the main ways that fish are identified is based on how the upper jaw connects to the rest of the skull," said Dr Tapanila.

"Because we have the upper jaw we can look at the bumps and grooves on it and see how it would have connected.

"It was fixed in two positions and was fused essentially to the brain tip... a feature that's distinctive for chimaeras and ratfish."

Following the reconstruction the jaw of the fish, the team is using inferred characteristics to create a scale model of the 4m animal for an exhibition at the Idaho State University Museum of Natural History this summer.

Based on fossil evidence, scientists believe the fish could have measured up to 7.6m long.

Laguna del Maule Volcano: Ground under ancient Chilean volcano is rising fast

Laguna del Maule in the Chilean Andes Mountains. Researchers have found uplift in part of the volcanic field.

Credit: Sarah Strierch / Wikimedia Commons

The Laguna del Maule volcanic field in the Chilean Andes Mountains lies in the heart of volcano country.

The region is a well-known subduction zone, where the friction of one crustal plate sliding under another heats rock to form magma.

But for the last 2,000 years, Laguna del Maule has been a quiet water-filled caldera.

Now, scientists are recording rapid deformation of the land around the caldera, suggesting that a magma reservoir is inflating below the surface.

Helene Le Mével of the University of Wisconsin – Madison, GeoScience dept, presented a poster at the American Geophysical Union’s Fall Meeting in San Francisco Wednesday to share the findings.

Researchers at the Southern Andean Volcano Observatory (OVDAS) monitor and archive volcanic activity throughout the region, but Le Mével said that until now, the observatory had no reason to focus on the Laguna del Maule field. “It’s such an old caldera that there’s nobody there,” she said.

Using a radar technique to measure changes in the level of the ground, Le Mével and her colleagues observed that several areas around and under the lake were rising.

When they set up three GPS stations to confirm this data, the results were startling: The ground is uplifting at a rate of almost 30 centimeters per year, and is now 1.4 meters higher than it was in 2007.

Using this information, the team found that the area is organized as a ring fault – a circular pattern of vents formed as land collapsed inward during the eruptions that created the volcano’s cauldron-like shape.

The area is of particular concern, Le Mével said, because the rock in this region contains a high concentration of silicon dioxide, the tough crystalline material used to make glass.

Unlike magma consisting mostly of basalt, found in the more “flowy” volcanoes of Hawaii, silicic magma very thick. It tends to build up in gluey domes under the surface, and then push upward in a violent explosion.

The scientists estimate that the horizontal reservoir of magma, called a sill, measures 7.5 by 5.5 km, and sits about 5 km underground. Not only is the sill growing, pushing up the earth above it, but its growth is also accelerating.

“At some point, a magma reservoir is always going to erupt when it’s ready, we just don’t know when,” said Le Mével.

She expects to see increasing seismicity right before the eruption, which she said could still be 1,000 years away. But she hopes this new evidence will be enough to fuel further research on the processes driving the deformation.

“We rarely observe large silicic systems that are likely to erupt, even if it’s not next week or next year. And so it’s going to be exciting to follow it. To see how it continues.”

Hublot Antikythera mechanism,100-year-old clockwork relic

It's a story of gigantic scientific upheaval, of adventure and shipwreck on the high seas, of war and death.

A story of amazing intellect, lost riches and impossible chance - a sunken treasure that Jaques Cousteau once described as "more valuable than the Mona Lisa" - and it's connected with an ancient celebrity whose star shone so brightly that he's still a household name more than 2200 years after his death.

There are few scientific or historic discoveries more significant than the one made by a Greek sponge diver in October 1900, on the Mediterranean sea bed.

Captain Kondos sent a team down to see if they might be able to pick up any more sponges while they waited for the storm to pass.

Within a short time, diver Elias Stadiatos resurfaced, raving like a lunatic. He reported finding a shipwreck on the sea bed 60 meters (197 feet) below, with hundreds of corpses and horses strewn about, in various stages of decay.

Far from a stack of corpses, what Kondos found made his sponge gathering mission pale in comparison.

A sunken ancient vessel, loaded with all kinds of loot and treasure. What Stadiatos had reported as rotting bodies were actually bronze statues that had been covered over by centuries' worth of sea floor debris.

The team scavenged what they could carry and took it back to Greece, where the Greek Education Ministry and Hellenic Navy quickly put together an expedition to explore the wreck more thoroughly.

Early indications were that the material on board dated back more than 2,000 years, into the fascinating historical period of the Roman Republic.

The collection itself was a celebrated find, but one anonymous chunk of rock sitting in a storage room had further riches to offer, when it broke apart and a caretaker noticed metallic gears within.

The Antikythera mechanism
Historians at the time largely ignored the device for one simple reason - the technology required to make such complex metallic gear systems simply didn't exist back in 100 B.C.

It appeared to have an epicyclic, or planetary gear system in it - and those hadn't popped up anywhere else in history for another 1900 years or so.

It was assumed that the machine had been misplaced, accidentally left with the wreckage, or wrongly catalouged, so it was shelved for another 49 years, until an English physicist called Derek Price decided to have a closer look in 1951.

With better technology and plenty of time at hand, Price soon realized that this was indeed an ancient device - in fact, there was some kind of instructive script carved into it, faded almost to obscurity, that put it right in the 100-300 B.C. period. This was a true Eureka moment - it put amazingly advanced technology in the hands of the Ancient Greeks.

In fact, it instantly became not only the world's earliest known use of planetary gears, but the first known mechanism that used clockwork gears at all. Various civilizations earlier than the Ancient Greeks had used wooden peg-in-hole gear systems to transfer motion, but this was an order of magnitude more complex than anything before it, and indeed anything for a millennium and a half after it.

Read More here