Mars volcanic deposit tells of warm and wet environment

Planetary scientists led by Brown University have found a volcanic deposit on Mars that would have been a promising wellspring for life. The silica deposit clearly shows the presence of water and heat. It was formed at a time when Mars' climate turned dry and chilly, which could mark it as one of the most recent habitable microenvironments on the red planet. The finding is published in Nature Geoscience.

Roughly 3.5 billion years ago, the first epoch on Mars ended. The climate on the red planet then shifted dramatically from a relatively warm, wet period to one that was arid and cold. Yet there was at least one outpost that scientists think bucked the trend.

A team led by planetary geologists at Brown University has discovered mounds of a mineral deposited on a volcanic cone less than 3.5 billion years ago that speak of a warm and wet past and may preserve evidence of one of the most recent habitable microenvironments on Mars.

Observations by NASA's Mars Reconnaissance Orbiter enabled researchers to identify the mineral as hydrated silica, a dead ringer that water was present at some time. That fact and the mounds' location on the flanks of a volcanic cone provide the best evidence yet found on Mars for an intact deposit from a hydrothermal environment -- a steam fumarole or a hot spring. Such environments may have provided habitats for some of Earth's earliest life forms.

"The heat and water required to create this deposit probably made this a habitable zone," said J.R. Skok, a graduate student at Brown and lead author of the paper in Nature Geoscience. "If life did exist there, this would be a promising spot where it would have been entombed -- a microbial mortuary, so to speak."

No studies have determined whether Mars has ever supported life, but this finding adds to accumulating evidence that at some times and in some places, Mars hosted favorable environments for microbial life. The deposit is located in the sprawling, flat volcanic zone known as Syrtis Major and was believed to have been left during the early Hesperian period, when most of Mars was already turning chilly and arid.

"Mars is just drying out," Skok said, "and this is one last hospitable spot in a cooling, drying Mars."

Concentrations of hydrated silica have been identified on Mars previously, including a nearly pure patch found by NASA's Mars Exploration Rover Spirit in 2007. However, this is the first found in an intact setting that clearly signals the mineral's origin.

"You have spectacular context for this deposit," Skok said. "It's right on the flank of a volcano. The setting remains essentially the same as it was when the silica was deposited."

The small, degraded cone rises about 100 meters from the floor of a shallow bowl named Nili Patera. The patera spans about 50 kilometers (30 miles) in Syrtis Major of equatorial Mars. Before the cone formed, free-flowing lava blanketed nearby plains. The collapse of an underground magma chamber from which lava had emanated created the bowl. Subsequent lava flows, still with a runny texture, coated the floor of Nili Patera. The cone grew from even later flows, apparently after evolution of the underground magma had thickened its texture so that the erupted lava would mound up.

"We can read a series of chapters in this history book and know that the cone grew from the last gasp of a giant volcanic system," said John "Jack" Mustard, professor of geological sciences and a co-author of the paper, who is Skok's thesis adviser at Brown. "The cooling and solidification of most of the magma concentrated its silica and water content."

Observations by cameras on the Mars Reconnaissance Orbiter revealed patches of bright deposits near the summit of the cone, fanning down its flank, and on flatter ground in the vicinity. The Brown researchers partnered with Scott Murchie of Johns Hopkins University Applied Physics Laboratory to analyze the bright exposures with the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the orbiter.

Silica can be dissolved, transported and concentrated by hot water or steam. Hydrated silica identified by the spectrometer in uphill locations -- confirmed by stereo imaging -- indicates that hot springs or fumaroles fed by underground heating created these deposits. Silica deposits around hydrothermal vents in Iceland are among the best parallels on Earth.

"The habitable zone would have been within and alongside the conduits carrying the heated water," Murchie said.

NASA funded the research.

Cassini sees Saturn rings oscillate like mini-galaxy

Scientists believe they finally understand why one of the most dynamic regions in Saturn's rings has such an irregular and varying shape, thanks to images captured by NASA's Cassini spacecraft. And the answer, published online in The Astronomical Journal, is this: The rings are behaving like a miniature version of our own Milky Way galaxy.

This new insight, garnered from images of Saturn's most massive ring, the B ring, may answer another long-standing question: What causes the bewildering variety of structures seen throughout the very densest regions of Saturn's rings?

Another finding from new images of the B ring's outer edge was the presence of at least two perturbed regions, including a long arc of narrow, shadow-casting peaks as high as 3.5 kilometers (2 miles) above the ring plane. The areas are likely populated with small moons that might have migrated across the outer part of the B ring in the past and got trapped in a zone affected by the moon Mimas' gravity. This process is commonly believed to have configured the present-day solar system.

"We have found what we hoped we'd find when we set out on this journey with Cassini nearly 13 years ago: visibility into the mechanisms that have sculpted not only Saturn's rings, but celestial disks of a far grander scale, from solar systems, like our own, all the way to the giant spiral galaxies," said Carolyn Porco, co-author on the new paper and Cassini imaging team lead, based at the Space Science Institute, Boulder, Colo.

New images and movies of the outer B ring edge can be found at http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://ciclops.org .

Since NASA's Voyager spacecraft flew by Saturn in 1980 and 1981, scientists have known that the outer edge of the planet's B ring was shaped like a rotating, flattened football by the gravitational perturbations of Mimas. But it was clear, even in Voyager's findings, that the outer B ring's behavior was far more complex than anything Mimas alone might do.

Now, analysis of thousands of Cassini images of the B ring taken over a four-year period has revealed the source of most of the complexity: at least three additional, independently rotating wave patterns, or oscillations, that distort the B ring's edge. These oscillations, with one, two or three lobes, are not created by any moons. They have instead spontaneously arisen, in part because the ring is dense enough, and the B ring edge is sharp enough, for waves to grow on their own and then reflect at the edge.

"These oscillations exist for the same reason that guitar strings have natural modes of oscillation, which can be excited when plucked or otherwise disturbed," said Joseph Spitale, lead author on the article and an imaging team associate at the Space Science Institute. "The ring, too, has its own natural oscillation frequencies, and that's what we're observing."

Astronomers believe such "self-excited" oscillations exist in other disk systems, like spiral disk galaxies and proto-planetary disks found around nearby stars, but they have not been able to directly confirm their existence. The new observations confirm the first large-scale wave oscillations of this type in a broad disk of material anywhere in nature.

Self-excited waves on small, 100-meter (300-foot) scales have been previously observed by Cassini instruments in a few dense ring regions and have been attributed to a process called "viscous overstability." In that process, the ring particles' small, random motions feed energy into a wave and cause it to grow. The new results confirm a Voyager-era predication that this same process can explain all the puzzling chaotic waveforms found in Saturn's densest rings, from tens of meters up to hundreds of kilometers wide.

"Normally viscosity, or resistance to flow, damps waves -- the way sound waves traveling through the air would die out," said Peter Goldreich, a planetary ring theorist at the California Institute of Technology in Pasadena. "But the new findings show that, in the densest parts of Saturn's rings, viscosity actually amplifies waves, explaining mysterious grooves first seen in images taken by the Voyager spacecraft."

The two perturbed B ring regions found orbiting within Mimas' zone of influence stretch along arcs up to 20,000 kilometers (12,000 miles) long. The longest one was first seen last year when the sun's low angle on the ring plane betrayed the existence of a series of tall structures through their long, spiky shadows. The small moons disturbing the material are probably hundreds of meters to possibly a kilometer or more in size.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

First evidence for magnetic field in protostar jet: Magnetism common to all cosmic jets?

Astronomers have found the first evidence of a magnetic field in a jet of material ejected from a young star, a discovery that points toward future breakthroughs in understanding the nature of all types of cosmic jets and of the role of magnetic fields in star formation.

Throughout the Universe, jets of subatomic particles are ejected by three phenomena: the supermassive black holes at the cores of galaxies, smaller black holes or neutron stars consuming material from companion stars, and young stars still in the process of gathering mass from their surroundings. Previously, magnetic fields were detected in the jets of the first two, but until now, magnetic fields had not been confirmed in the jets from young stars.

"Our discovery gives a strong hint that all three types of jets originate through a common process," said Carlos Carrasco-Gonzalez, of the Astrophysical Institute of Andalucia Spanish National Research Council (IAA-CSIC) and the National Autonomous University of Mexico (UNAM).

The astronomers used the National Science Foundation's Very Large Array (VLA) radio telescope to study a young star some 5,500 light-years from Earth, called IRAS 18162-2048. This star, possibly as massive as 10 Suns, is ejecting a jet 17 light-years long.

Observing this object for 12 hours with the VLA, the scientists found that radio waves from the jet have a characteristic indicating they arose when fast-moving electrons interacted with magnetic fields. This characteristic, called polarization, gives a preferential alignment to the electric and magnetic fields of the radio waves.

"We see for the first time that a jet from a young star shares this common characteristic with the other types of cosmic jets," said Luis Rodriguez, of UNAM.

The discovery, the astronomers say, may allow them to gain an improved understanding of the physics of the jets as well as of the role magnetic fields play in forming new stars. The jets from young stars, unlike the other types, emit radiation that provides information on the temperatures, speeds, and densities within the jets. This information, combined with the data on magnetic fields, can improve scientists' understanding of how such jets work.

"In the future, combining several types of observations could give us an overall picture of how magnetic fields affect the young star and all its surroundings. This would be a big advance in understanding the process of star formation," Rodriguez said.

Carrasco-Gonzalez and Rodriguez worked with Guillem Anglada and Mayra Osorio of the Astrophysical Institute of Andalucia, Josep Marti of the University of Jaen in Spain, and Jose Torrelles of the University of Barcelona. The scientists reported their findings in the November 26 edition of Science.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Large Hadron Collider experiments bring new insight into primordial universe

After less than three weeks of heavy-ion running, the three experiments studying lead ion collisions at the Large Hadron Collider have already brought new insight into matter as it would have existed in the very first instants of the Universe's life. The ALICE experiment, which is optimised for the study of heavy ions, published two papers just a few days after the start of lead-ion running.

Now, the first direct observation of a phenomenon known as jet quenching has been made by both the ATLAS and CMS collaborations. This result is reported in a paper from the ATLAS collaboration accepted for publication in the journal Physical Review Letters. A CMS paper will follow shortly, and results from all of the experiments will be presented at a seminar on Dec. 2 at CERN (the European Organization for Nuclear Research). Data taking with ions continues to Dec. 6.

"It is impressive how fast the experiments have arrived at these results, which deal with very complex physics," said CERN's Research Director Sergio Bertolucci. "The experiments are competing with each other to publish first, but then working together to assemble the full picture and cross check their results. It's a beautiful example of how competition and collaboration is a key feature of this field of research."

One of the primary goals of the lead-ion programme at CERN is to create matter as it would have been at the birth of the Universe. Back then, the ordinary nuclear matter of which we and the visible universe are made could not have existed: conditions would have been too hot and turbulent for quarks to be bound up by gluons into protons and neutrons, the building blocks of the elements. Instead, these elementary particles would have roamed freely in a sort of quark gluon plasma. Showing beyond doubt that we can produce and study quark gluon plasma will bring important insights into the evolution of the early Universe, and the nature of the strong force that binds quarks and gluons together into protons, neutrons and ultimately all the nuclei of the periodic table of the elements.

When lead-ions collide in the LHC, they can concentrate enough energy in a tiny volume to produce tiny droplets of this primordial state of matter, which signal their presence by a wide range of measureable signals. The ALICE papers point to a large increase in the number of particles produced in the collisions compared to previous experiments, and confirm that the much hotter plasma produced at the LHC behaves as a very low viscosity liquid (a perfect fluid), in keeping with earlier observations from Brookhaven's RHIC collider. Taken together, these results have already ruled out some theories about how the primordial Universe behaved.

"With nuclear collisions, the LHC has become a fantastic 'Big Bang' machine," said ALICE spokesperson Jürgen Schukraft. "In some respects, the quark-gluon matter looks familiar, still the ideal liquid seen at RHIC, but we're also starting to see glimpses of something new"

The ATLAS and CMS experiments play to the strength of their detectors, which both have very powerful and hermetic energy measuring capability. This allows them to measure jets of particles that emerge from collisions. Jets are formed as the basic constituents of nuclear matter, quarks and gluons, fly away from the collision point. In proton collisions, jets usually appear in pairs, emerging back to back. However, in heavy ion collisions the jets interact in the tumultuous conditions of the hot dense medium. This leads to a very characteristic signal, known as jet quenching, in which the energy of the jets can be severely degraded, signalling interactions with the medium more intense than ever seen before. Jet quenching is a powerful tool for studying the behaviour of the plasma in detail.

"ATLAS is the first experiment to report direct observation of jet quenching," said ATLAS Spokesperson Fabiola Gianotti. "The excellent capabilities of ATLAS to determine jet energies enabled us to observe a striking imbalance in energies of pairs of jets, where one jet is almost completely absorbed by the medium. It's a very exciting result of which the Collaboration is proud, obtained in a very short time thanks in particular to the dedication and enthusiasm of young scientists."

"It is truly amazing to be looking, albeit on a microscopic scale, at the conditions and state of matter that existed at the dawn of time," said CMS Spokesperson Guido Tonelli. "Since the very first days of lead-ion collisions the quenching of jets appeared in our data while other striking features, like the observation of Z particles, never seen before in heavy-ion collisions, are under investigation. The challenge is now to put together all possible studies that could lead us to a much better understanding of the properties of this new, extraordinary state of matter"

The ATLAS and CMS measurements herald a new era in the use of jets to probe the quark gluon plasma. Future jet quenching and other measurements from the three LHC experiments will provide powerful insight into the properties of the primordial plasma and the interactions among its quarks and gluons.

With data taking continuing for over one more week, and the LHC already having delivered the programmed amount of data for 2010, the heavy-ion community at the LHC is looking forward to further analysing their data, which will greatly contribute to the emergence of a more complete model of quark gluon plasma, and consequently the very early Universe.

NASA's Stardust spacecraft burns for another comet flyby

Eighty-six days out from its appointment with a comet, NASA's Stardust spacecraft fired its thrusters to help refine its flight path. The Stardust-NExT mission will fly past comet Tempel 1 next Valentine's Day (Feb. 14, 2011). It will perform NASA's second comet flyby within four months.

"One comet down, one to go," said Tim Larson, project manager for both the Stardust-NExT mission and the EPOXI mission -- which successfully flew past comet Hartley 2 on Nov. 4.

The trajectory correction maneuver, which adjusts the spacecraft's flight path, began at 2 p.m. EST (11:00 a.m. PST) on Nov. 20. The Stardust spacecraft's rockets fired for 9 seconds, consumed about 41 grams (1.4 ounces) of fuel and changed the spacecraft's speed by all of 0.33 meters per second (about 0.7 miles per hour). The maneuver was designed to target a point in space 200 kilometers (124 miles) from comet Tempel 1.

Launched on Feb. 7, 1999, Stardust became the first spacecraft in history to collect samples from a comet (comet Wild 2), and return them to Earth for study. While its sample return capsule parachuted to Earth in January 2006, mission controllers were placing the still viable spacecraft on a path that would allow NASA the opportunity to re-use the already-proven flight system if a target of opportunity presented itself. In January 2007, NASA re-christened the mission "Stardust-NExT" (New Exploration of Tempel), and the Stardust team began a four-and-a-half year journey for the spacecraft to comet Tempel 1. This will be the second exploration of Tempel 1 by a spacecraft (Deep Impact).

Along with the high-resolution images of the comet's surface, Stardust-NExT will also measure the composition, size distribution and flux of dust emitted into the coma, and provide important new information on how Jupiter family comets evolve and how they formed 4.6 billion years ago.

Stardust-NExT is a low-cost mission that will expand the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology in Pasadena, manages Stardust-NExT for the NASA Science Mission Directorate, Washington, D.C. Joe Veverka of Cornell University, Ithaca, N.Y., is the mission's principal investigator. Lockheed Martin Space Systems, Denver, built the spacecraft and manages day-to-day mission operations.

For more information about Stardust-NExT, visit: http://stardustnext.jpl.nasa.gov .

An exploration of the atomic nucleus: fundamental science, real world applications

The visible matter that makes up all things around us, from the stars, planets, to our earth and every living organism that lives on it, has existed for billions of years. However, nuclear scientists around the world have only recently had the knowledge and tools necessary to begin to understand how this matter has been formed, how it evolved and where it originated. We now know there is a strong interplay between the often violent events in the cosmos and the nuclei which make up the elements we find on earth today.

Nuclear scientists are striving to push towards the nucleus towards its limits of stability, to search for new elements and to understand how the elements were formed in the universe. Driven by this mission to understand the world around us, basic research in science has led to numerous applications that impact our daily lives. Nuclear science has contributed directly in areas such as energy production and medicine, and indirectly through the training of young people who will be the scientists and pioneers of the discoveries of tomorrow.

The new cyclotron and the laboratory extension benefit physics research, medical industry and the control of the nuclear test ban treaty.

The new cyclotron of the Department of Physics of the University of Jyväskylä was inaugurated on 15 November 2010 by the Finnish Minister of Education, Henna Virkkunen and the Rector of the University of Jyväskylä, Aino Sallinen.

"The new accelerator and the laboratory extension building for it are the largest single investment in the scientific infrastructure in Finland in recent years. The main use of the cyclotron will be the fundamental research of nuclear physics," says Professor Juha Äystö. The research using the most intense proton beam, the IGISOL mass separator, is moved next to the new cyclotron.

A significant part of the research is related to the nuclear fission of uranium and thorium. In this research, accurate nuclear data are measured to be used as a basis of computer simulations of the next generation nuclear reactors. This way, the research supports development of safer and cleaner nuclear power plants. This research is done in international collaboration, partly supported by the European Union.

Jyväskylä is the world's only producer of calibration radiation sources.

Fission is also utilized in the production of calibration radiation sources. These special radiation sources are needed for the Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO) detector network calibrations. Calibration of the CTBTO's radiation detectors with these special sources improves their sensitivity and allows identifying the weakest signs of radioactivity due to nuclear explosions.

Resources of the new laboratory can also be used for developing research instrumentation that will be used in other international laboratories. The most important of these laboratories is the international Facility for Antiproton and Ion Research (FAIR), the realisation of which will be supported by Finland by six million euros.

The Accelerator Laboratory of the University of Jyväskylä is assigned as a Finnish Center of Excellence by the Academy of Finland. It is also one of the national level research infrastructures listed by the Finnish Ministry of Education. It also has a national task designated by the Ministry of Education as a centre of expertise in radiation and ion-beam research, education and applications. The accelerator laboratory is recognized by the Nuclear Physics European Collaboration Committee (NuPECC) as one of the leading stable-ion beam facilities in Europe. In addition, it is recognized by the European Space Agency (ESA) as an official radiation test facility for space electronics. The foreign investments to the infrastructure of the accelerator laboratory exceed 10 million euros.

The new accelerator will be also utilized in the production of the radioisotopes used in medical imaging.

The new accelerator of the laboratory, a Russian made MCC30/15 cyclotron, accelerates protons (hydrogen nuclei) to energy equivalent to a voltage of 30 million volt. The accelerator was delivered to Jyväskylä as a compensation for the national debt of the former Soviet Union to Finland. The agreement of the delivery was signed in 2007. The main parts of the cyclotron were delivered to Jyväskylä in August 2009, and the installation of cyclotron was finished by spring 2010.