News Astronomy

Space / Astronomy News and Articles

Mon04212014

Last update01:23:23 PM GMT

Back Solar System Asteroids, Comets & Meteors

Asteroids, Comets and Meteors

Mars' Reull Vallis: A river ran through it

  • PDF

Topographic view of Reull Vallis: This colour-coded overhead view is based on an ESA Mars Express HRSC digital terrain model of the Reull Vallis region, from which the topography of the landscape can be derived. The colour coding shows the depth of the main channel, coloured in blue, which contrasts clearly against the Promethei Terra Highlands and their smooth, soft and rounded mountain tops. Centred at around 41°S and 107°E, the image has a ground resolution of about 16 m per pixel. The image was taken during revolution 10657 on 14 May 2012. (Credit: ESA/DLR/FU Berlin (G. Neukum))

Jan. 22, 2013 — ESA's Mars Express imaged the striking upper part of the Reull Vallis region of Mars with its high-resolution stereo camera last year.

Reull Vallis, the river-like structure in these images, is believed to have formed when running water flowed in the distant martian past, cutting a steep-sided channel through the Promethei Terra Highlands before running on towards the floor of the vast Hellas basin.

This sinuous structure, which stretches for almost 1500 km across the martian landscape, is flanked by numerous tributaries, one of which can be clearly seen cutting in to the main valley towards the upper (north) side.

The new Mars Express images show a region of Reull Vallis at a point where the channel is almost 7 km wide and 300 m deep.

The sides of Reull Vallis are particularly sharp and steep in these images, with parallel longitudinal features covering the floor of the channel itself. These structures are believed to be caused by the passage of loose debris and ice during the 'Amazonian' period (which continues to this day) due to glacial flow along the channel.

The structures were formed long after it was originally carved by liquid water during the Hesperian period, which is believed to have ended between 3.5 billion and 1.8 billion years ago.

Similar lineated structures, believed to be rich in ice, can also be found in many of the surrounding craters.

In the wider context image, the tributary intersecting the main channel appears to be part of a forking of the main valley into two distinct branches further upstream before merging back into a single main valley.

The right (northern) part of the main image is dominated by the Promethei Terra Highlands with their high and soft-rounded mountains shown in these images, rising around 2500 m above the surrounding flat plains.

The perspective view below shows one of these mountains with nearby sediment-filled impact craters.

This region shows a striking resemblance to the morphology found in regions on Earth affected by glaciation. For example, we can see circular step-like structures on the inner walls of the sediment-filled crater in the foreground of the second perspective view. Planetary scientists think that these may represent former high water or glacial levels, before ice and water sublimated or evaporated away in stages at various times.

The morphology of Reull Vallis suggests it has experienced a diverse and complex history, with analogies seen in glacial activity on Earth. These analogies are giving planetary geologists tantalising glimpses of a past on the Red Planet not too dissimilar to events on our own world today.


Story Source:

The above story is reprinted from materials provided by European Space Agency.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Mars may have supported life: Martian underground could contain clues to life's origins

  • PDF

This view of layered rocks on the floor of McLaughlin Crater shows sedimentary rocks that contain spectroscopic evidence for minerals formed through interaction with water. (Credit: NASA/JPL-Caltech/Univ. of Arizona)

Jan. 20, 2013 — Minerals found in the subsurface of Mars, a zone of more than three miles below ground, make for the strongest evidence yet that the red planet may have supported life, according to research "Groundwater activity on Mars and implications for a deep biosphere," published in Nature Geoscience on January 20, 2013.

Up to half of all life on Earth consists of simple microorganisms hidden in rocks beneath the surface and for some time, scientists have suggested that the same may be true for Mars. Now this theory has been supported by new research, which suggests that the ingredients for life have been present in the Martian subsurface for much of the planet's history.

When meteorites strike the surface of Mars, they act like natural probes, bringing up rocks from far beneath the surface. Recent research has shown that many of the rocks brought up from the Martian subsurface contain clays and minerals whose chemical make-up has been altered by water, an essential element to support life. Some deep craters on Mars also acted as basins where groundwater likely emerged to produce lakes.

McLaughlin Crater, described in this study, is one such basin that contains clay and carbonate minerals formed in an ancient lake on Mars. The fluids that formed these minerals could carry clues to as to whether the subsurface contained life.

"We don't know how life on Earth formed but it is conceivable that it originated underground, protected from harsh surface conditions that existed on early Earth. Due to plate tectonics, however, the early geological record of Earth is poorly preserved so we may never know what processes led to life's origin and early evolution," said Dr Joseph Michalski, lead author and planetary geologist at the Natural History Museum in London. "Exploring these rocks on Mars, where the ancient geologic record is better preserved than on Earth, would be like finding a stack of pages that have been ripped out of Earth's geological history book. Whether the Martian geologic record contains life or not, analysis of these types of rocks would certainly teach us a tremendous amount about early chemical processes in the solar system."

Co-author Deanne Rogers, Assistant Professor in the Department of Geosciences at Stony Brook University used data from the Thermal Emission Spectrometer aboard NASA's Mars Global Surveyor and the Thermal Emission Imaging System aboard the Mars Odyssey orbiter to detect and identify minerals that proved to be consistent with a sustained aqueous environment on the floor of the McLaughlin Crater.

"Our understanding of Mars is changing very rapidly with all of the new mission data," said Professor Rogers. "There have been several recent observations and models that have pointed to the possibility of a vast store of groundwater in the Martian past, and perhaps present. So you might expect that deep basins such as McLaughlin, which intersect the upwelling groundwater table, would contain evidence of this water. And this study found that evidence."

Current exploration of Mars focuses on investigating surface processes because sedimentary rocks are most likely to provide the best chance evidence for habitability. Evidence suggests, however, that the Martian surface environment has been quite inhospitable to life for billions of years. In future missions, scientists could choose to target rocks related to the surface or subsurface, or perhaps do both by targeting areas where sedimentary rocks formed from subsurface fluids.

Michalski concludes: 'In this paper, we present a strong case for exploring the subsurface, as well as the surface. But I don't personally think we should try to drill into the subsurface to look for ancient life. Instead, we can study rocks that are naturally brought to the surface by meteor impact and search in deep basins where fluids have come to the surface.'

Co-author Professor John Parnell, geochemist at the University of Aberdeen, commented, "This research has demonstrated how studies of Earth and Mars depend on each other. It is what we have observed of microbes living below the continents and oceans of Earth. They allow us to speculate on habitats for past life on Mars, which in turn show us how life on the early Earth could have survived. We know from Earth's history that planets face traumatic conditions such as meteorite bombardment and ice ages, when the survival of life may depend on being well below ground. So it makes sense to search for evidence of life from that subsurface environment, in the geological records of both Earth and Mars. But it's one thing to do that on Earth -- we need to be clever in finding a way to do it on Mars."

Additional co-authors of the study include: Javier Caudros, Researcher, Clay Mineralogy, Earth Sciences Department, Natural History Museum, London; Paul B. Niles, Planetary Scientist, NASA Johnson Space Center; and Shawn P. Wright, Postdoctoral Fellow in Geology, Auburn University.


Story Source:

The above story is reprinted from materials provided by Stony Brook University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Joseph R. Michalski, Javier Cuadros, Paul B. Niles, John Parnell, A. Deanne Rogers, Shawn P. Wright. Groundwater activity on Mars and implications for a deep biosphere. Nature Geoscience, 2013; DOI: 10.1038/ngeo1706

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Asteroid deflection mission seeks smashing ideas

  • PDF

AIDA mission concept: The US-European Asteroid Impact and Deflection mission – AIDA. This innovative but low-budget transatlantic partnership involves the joint operations of two small spacecraft sent to intercept a binary asteroid. The first Double Asteroid Redirection Test (DART) spacecraft, designed by the US Johns Hopkins Applied Physics Laboratory will collide with the smaller of the two asteroids. Meanwhile, ESA’s Asteroid Impact Monitor (AIM) craft will survey these bodies in detail, before and after the collision. The impact should change the pace at which the objects spin around each other, observable from Earth. But AIM’s close-up view will ‘ground-truth’ such observations. (Credit: Image courtesy of European Space Agency)

Jan. 15, 2013 — A space rock several hundred metres across is heading towards our planet and the last-ditch attempt to avert a disaster -- an untested mission to deflect it -- fails. This fictional scene of films and novels could well be a reality one day. But what can space agencies do to ensure it works?

ESA is appealing for research ideas to help guide the development of a US-European asteroid deflection mission now under study.

Concepts are being sought for both ground- and space-based investigations, seeking improved understanding of the physics of very high-speed collisions involving both human-made and natural objects in space.

AIDA: double mission to a double asteroid

ESA's call will help to guide future studies linked to the Asteroid Impact and Deflection mission -- AIDA.

This innovative but low-budget transatlantic partnership involves the joint operations of two small spacecraft sent to intercept a binary asteroid.

The first Double Asteroid Redirection Test (DART) spacecraft, designed by the US Johns Hopkins Applied Physics Laboratory will collide with the smaller of the two asteroids.

Meanwhile, ESA's Asteroid Impact Monitor (AIM) craft will survey these bodies in detail, before and after the collision.

The impact should change the pace at which the objects spin around each other, observable from Earth. But AIM's close-up view will 'ground-truth' such observations.

"The advantage is that the spacecraft are simple and independent," says Andy Cheng of Johns Hopkins, leading the AIDA project on the US side. "They can both complete their primary investigation without the other one."

But by working in tandem, the quality and quantity of results will increase greatly, explains Andrés Gálvez, ESA AIDA study manager: "Both missions become better when put together -- getting much more out of the overall investment.

"And the vast amounts of data coming from the joint mission should help to validate various theories, such as our impact modelling."


Story Source:

The above story is reprinted from materials provided by European Space Agency.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

NASA rules out Earth impact in 2036 for asteroid Apophis

  • PDF

Asteroid Apophis was discovered on June 19, 2004. (Credit: UH/IA)

Jan. 11, 2013 — NASA scientists at the agency's Jet Propulsion Laboratory in Pasadena, Calif., effectively have ruled out the possibility the asteroid Apophis will impact Earth during a close flyby in 2036. The scientists used updated information obtained by NASA-supported telescopes in 2011 and 2012, as well as new data from the time leading up to Apophis' distant Earth flyby Jan. 9, 2013.

Discovered in 2004, the asteroid, which is the size of three-and-a-half football fields, gathered the immediate attention of space scientists and the media when initial calculations of its orbit indicated a 2.7 percent possibility of an Earth impact during a close flyby in 2029. Data discovered during a search of old astronomical images provided the additional information required to rule out the 2029 impact scenario, but a remote possibility of one in 2036 remained -- until Wednesday.

"With the new data provided by the Magdalena Ridge [New Mexico Institute of Mining and Technology] and the Pan-STARRS [Univ. of Hawaii] optical observatories, along with very recent data provided by the Goldstone Solar System Radar, we have effectively ruled out the possibility of an Earth impact by Apophis in 2036," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at JPL. "The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future."

The April 13, 2029, flyby of asteroid Apophis will be one for the record books. On that date, Apophis will become the closest flyby of an asteroid of its size when it comes no closer than 19, 400 miles (31,300 kilometers) above Earth's surface.

"But much sooner, a closer approach by a lesser-known asteroid is going to occur in the middle of next month when a 40-meter-sized asteroid, 2012 DA14, flies safely past Earth's surface at about 17,200 miles," said Yeomans. "With new telescopes coming online, the upgrade of existing telescopes and the continued refinement of our orbital determination process, there's never a dull moment working on near-Earth objects."

NASA detects and tracks asteroids and comets passing close to Earth using both ground and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.

The Near-Earth Object Program Office at JPL manages the technical and scientific activities for NASA's Near-Earth Object Program of the Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Oxygen to the core: Earth's core formed under more oxidizing conditions than previously proposed

  • PDF

An artist's conception of Earth's inner and outer core. (Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory)

Jan. 10, 2013 — An international collaboration including researchers from Lawrence Livermore National Laboratory has discovered that Earth's core formed under more oxidizing conditions than previously proposed.

Through a series of laser-heated diamond anvil cell experiments at high pressure (350,000 to 700,000 atmospheres of pressure) and temperatures (5,120 to 7,460 degrees Fahrenheit), the team demonstrated that the depletion of siderophile (also known as "iron loving") elements can be produced by core formation under more oxidizing conditions than earlier predictions.

"We found that planet accretion (growth) under oxidizing conditions is similar to those of the most common meteorites," said LLNL geophysicist Rick Ryerson.

The research appears in the Jan. 10 edition of Science Express.

While scientists know that Earth accreted from some mixture of meteoritic material, there is no simple way to quantify precisely the proportions of these various materials. The new research defines how various materials may have been distributed and transported in the early solar system.

As core formation and accretion are closely linked, constraining the process of core formation allows researchers to place limits on the range of materials that formed our planet, and determine whether the composition of those materials changed with time. (Was accretion heterogeneous or homogeneous?)

"A model in which a relatively oxidized Earth is progressively reduced by oxygen transfer to the core-forming metal is capable of reconciling both the need for light elements in the core and the concentration of siderophile elements in the silicate mantle, and suggests that oxygen is an important constituent in the core," Ryerson said.

The experiments demonstrated that a slight reduction of such siderphile elements as vanadium (V) and chromium (Cr) and moderate depletion of nickel (Ni) and cobalt (Co) can be produced during core formation, allowing for oxygen to play a more prominent role.

Planetary core formation is one of the final stages of the dust-to-meteorite-to-planet formation continuum. Meteorites are the raw materials for planetary formation and core formation is a process that leads to chemical differentiation of the planet. But meteorite formation and core formation are very different processes, driven by different heat sources and occurring in very different pressure and temperature ranges.

"Our ability to match the siderophile element signature under more oxidizing conditions allows us to accrete Earth from more common, oxidized meteoritic materials, such as carbonaceous and ordinary chondrites," Ryerson said.

Earth's magnetic field is generated in the core, and protects Earth from the solar wind and associated erosion of the atmosphere. While the inner core of Earth is solid, the outer core is still liquid. The ability to preserve a liquid outer core and the associated magnetic field are dependent on the composition of the core and the concentration of light elements that may reduce the melting temperature.

"By characterizing the chemical interactions that accompany separation of core-forming melts from the silicate magma ocean, we can hope to provide additional constraints on the nature of light elements in the present-day core and its melting/freezing behavior," Ryerson said.

Other teams members include Julien Siebert and Daniele Antonangeli (former LLNL postdocs) from the Université Pierre et Marie Curie, and James Badro (a faculty scholar at LLNL) from the Institut de Physique du Globe de Paris.


Story Source:

The above story is reprinted from materials provided by DOE/Lawrence Livermore National Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Julien Siebert, James Badro, Daniele Antonangeli, and Frederick J. Ryerson. Terrestrial Accretion Under Oxidizing Conditions. Science, 10 January 2013 DOI: 10.1126/science.1227923

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

NASA's robotic refueling demo set to jumpstart expanded capabilities in space

  • PDF

The Robotic Refueling Mission, or RRM, investigation (center, on platform) uses the International Space Station’s Canadarm2 and the Canadian Dextre robot (right) to demonstrate satellite-servicing tasks. (Credit: NASA)

Jan. 10, 2013 — In mid-January, NASA will take the next step in advancing robotic satellite-servicing technologies as it tests the Robotic Refueling Mission, or RRM aboard the International Space Station. The investigation may one day substantially impact the many satellites that deliver products Americans rely upon daily, such as weather reports, cell phones and television news.

During five days of operations, controllers from NASA and the Canadian Space Agency will use the space station's remotely operated Special Purpose Dexterous Manipulator, or Dextre, robot to simulate robotic refueling in space. Operating a space-based robotic arm from the ground is a feat on its own, but NASA will do more than just robotics work as controllers remotely snip wires, unscrew caps and transfer simulated fuel. The team also will demonstrate tools, technologies and techniques that could one day make satellites in space greener, more robust and more capable of delivering essential services to people on Earth.

Why Fix or Refuel a Satellite?

"Every satellite has a lifespan and eventual retirement date, determined by the reliability of its components and how much fuel it can carry," explains Benjamin Reed, deputy project manager of NASA's Satellite Servicing Capabilities Office, or SSCO.

Repairing and refueling satellites already in place, Reed asserts, can be far less expensive than building and launching entirely new spacecraft, potentially saving millions, even billions of dollars and many years of work.

The RRM demonstration specifically tests what it would take to repair and refuel satellites traveling the busy space highway of geosynchronous Earth orbit, or GEO. Located about 22,000 miles above Earth, this orbital path is home to more than 400 satellites, many of which beam communications, television and weather data to customers worldwide.

By developing robotic capabilities to repair and refuel GEO satellites, NASA hopes to add precious years of functional life to satellites and expand options for operators who face unexpected emergencies, tougher economic demands and aging fleets. NASA also hopes that these new technologies will help boost the commercial satellite-servicing industry that is rapidly gaining momentum.

Besides aiding the GEO satellite community, a capability to fix and relocate "ailing" satellites also could help manage the growing orbital debris problem that threatens continued space operations, ultimately making space greener and more sustainable.

How RRM Is Making a Difference

Built by SSCO in the span of 18 months, the washing-machine-sized RRM module contains the components, activity boards and tools to practice several of the tasks that would be performed in orbit during a real servicing mission. Launched to the space station on July 8, 2011, aboard the final mission of the Space Shuttle Program, RRM was the last payload an astronaut ever removed from a shuttle.

In 2012, RRM demonstrated dexterous robotic operations in space. Dextre's 12-foot arm and accompanying RRM tool successfully snipped two twisted wires -- each the thickness of two sheets of paper -- with only a few millimeters of clearance: a task essential to the satellite refueling process.

The RRM refueling demonstration on Jan. 14-24 will employ the Canadian-built Dextre, NASA's RRM module and four unique RRM tools to show that space robots controlled from Earth -- hundreds or even thousands of miles below -- can transfer fuel to satellites with triple-sealed valves that were never designed to be accessed.

"The RRM operations team is very excited about the upcoming refueling demonstration," says Charlie Bacon, RRM operations manager. "Over the last two years, the team has put in more than 300 hours of preparation -- reviewing procedures, running simulations, and communicating with team members from other NASA centers and our international partners. When we finally execute the namesake task of RRM, we anticipate that our work will culminate in proving that in-orbit satellite refueling is no longer future technology -- it's current technology."

Although the RRM module will never fix or refuel a satellite itself, its advanced tools and practice runs are laying the foundation for future in-orbit robotic servicing missions. Additional RRM demonstrations will continue into 2013, with a new round of servicing task boards, tools and activities slated to continue its investigations through 2015.

What's Next in Robotic Satellite Servicing?

The satellite-servicing concept that RRM is advancing is one that NASA has been developing for years. Beginning with the Solar Maximum repair mission in 1984, the servicing philosophy paved the way for five successful astronaut-based missions to upgrade and repair the Hubble Space Telescope and has been practiced more recently in spacewalks to assemble and maintain the space station.

With the RRM on the space station and a robust technology development campaign being conducted on the ground, NASA is testing capabilities for a new robotic servicing frontier. Since 2009, the Satellite Servicing Capabilities Office at NASA's Goddard Space Flight Center in Greenbelt, Md., has been aggressively advancing the robotic technologies for a free-flying servicer spacecraft that could access, repair and refuel satellites in GEO.

To this end, the SSCO team has been studying a conceptual servicing mission and building technologies to address uncharted territory such as autonomous rendezvous and docking, propellant transfer systems for zero gravity and specialized algorithms (computer commands) to orchestrate and synchronize satellite-servicing operations. A systems engineering review on this conceptual mission was recently conducted with positive responses from peer experts and external participants.

Reed and the SSCO team see many applications across NASA for these new, game-changing capabilities.

"The technologies we're building to help rescue satellites in five years could be the very same ones used to clean up space ten years in the future or save a spacecraft on the way to Mars 30 years from now," says Reed. "NASA is acting today to ensure that we have the capabilities America needs for the future. With satellite servicing technologies, we're bolstering the agency's long-term strategy as we invest in near-term tactical technology investments. RRM is just the beginning."


Story Source:

The above story is reprinted from materials provided by NASA/Goddard Space Flight Center. The original article was written by Adrienne Alessandro.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Herschel spacecraft eyes asteroid Apophis

  • PDF

The Photodetecting Array Camera and Spectrometer instrument aboard the European Space Agency's Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on Jan. 5 and 6, 2013. (Credit: ESA/Herschel/PACS/MACH-11/MPE/ESAC)

Jan. 9, 2013 — Scientists using the Herschel Space Observatory made new observations of asteroid Apophis as it approached Earth this past weekend. The data show the asteroid to be bigger than first estimated, and less reflective.

Discovered in 2004, Apophis was initially thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteroid ruled out any possibility of an impact in 2029. However, Apophis is expected to make a record-setting -- but harmless -- close approach to Earth on April 13, 2029, when it comes no closer than 18,300 miles (29,450 kilometers) above Earth's surface. The asteroid will make another approach to Earth in 2036. Data collected by telescopes during today's close approach are expected to refine the asteroid's orbit to the point where an impact in 2036 can be ruled out.

The Herschel Observatory is a European Space Agency mission in which NASA plays an important role.

Over the weekend, Herschel gathered data while observing Apophis for about two hours on its approach to Earth, ahead of today's closest encounter at a little less than one-tenth of the distance from Earth to the sun: about 9 million miles (14.5 million kilometers). The space observatory provided the first thermal infrared observations of Apophis at different wavelengths, which together with optical measurements helped refine estimates of the asteroid's properties. Previous estimates bracketed the asteroid's average diameter at about 885 feet (270 meters). Herschel's observations indicate the space rock is about 1,060 feet (325 meters) across.

By analyzing the heat emitted by Apophis, Herschel also provided a new estimate of the asteroid's albedo -- a measure of its reflectivity-- of 0.23. This value means that 23 percent of the sunlight falling onto the asteroid is reflected; the rest is absorbed and heats up the asteroid. The previous albedo estimate for Apophis was 0.33.


Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

First meteorite linked to Martian crust

  • PDF

The unusual Martian meteorite, Northwest Africa (NWA) 7034, is the first meteorite that scientists have found linked to the Martian crust. (Credit: Image courtesy Carl Agee, University of New Mexico)

Jan. 3, 2013 — After extensive analyses by a team of scientists led by Carl Agee at the University of New Mexico, researchers have identified a new class of Martian meteorite that likely originated from Mars's crust. It is also the only meteoritic sample dated to 2.1 billion years ago, the early era of the most recent geologic epoch on Mars, an epoch called the Amazonian. The meteorite was found to contain an order of magnitude more water than any other Martian meteorite.

Researchers from the Carnegie Institution (Andrew Steele, Marilyn Fogel, Roxane Bowden, and Mihaela Glamoclija) studied carbon in the meteorite and have shown that organic carbon (macromolecular) similar to that seen in other Martian meteorites is also found in this meteorite.

The research is published in the January 3, 2013, issue of Science Express.

The unique meteorite, dubbed Northwest Africa (NWA) 7034, has some similarities to, but is very different from other Martian meteorites known as SNC (for three members of the group: Shergotty, Nakhla, and Chassigny). SNC meteorites currently number 110. And so far they are the only meteoritic samples from Mars that scientists have been able to study. However, their point of origin on the Red Planet is not known. In fact, recent data from lander and orbiter missions suggest that they are a mismatch for the Martian crust.

As co-author Andrew Steele, who led the carbon analysis at the Carnegie Institution's Geophysical Laboratory explained: "The texture of the NWA meteorite is not like any of the SNC meteorites. It is made of cemented fragments of basalt, rock that forms from rapidly cooled lava, dominated with feldspar and pyroxene, most likely from volcanic activity. This composition is common for lunar samples, but not from other Martian meteorites. This unusual meteorite's chemistry suggests it came from the Martian crust. It is the first link thus far of any meteorite to the crust. Our carbon analysis also showed the presence of macromolecular organic carbon in feldspar grains associated with iron oxides, hinting that perhaps there is a different non-biological process at work than that explaining the presence of macromolecular carbon in other Martian meteorites."

Lead author Agee, of the Institute of Meteoritics at the University of New Mexico, remarked: "The basaltic rock in this meteorite is consistent with the crust or upper mantle of Mars based on findings from recent Martian rovers and orbiters. Our analysis of the oxygen isotopes shows that NWA 7034 is not like any other meteorites or planetary samples. The chemistry is consistent with a surface origin and an interaction with the Martian atmosphere. The abundance of water, some 6000 parts per million, suggests that the meteorite interacted with the Martian surface some 2.1 billion years ago."

"Perhaps most exciting, is that the high water content could mean there was an interaction of the rocks with surface water either from volcanic magma, or from fluids from impacting comets during that time," said Steele. "It is the richest Martian meteorite geochemically and further analyses are bound to unleash more surprises."


Story Source:

The above story is reprinted from materials provided by Carnegie Institution.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Carl B. Agee, Nicole V. Wilson, Francis M. McCubbin, Karen Ziegler, Victor J. Polyak, Zachary D. Sharp, Yemane Asmerom, Morgan H. Nunn, Robina Shaheen, Mark H. Thiemens, Andrew Steele, Marilyn L. Fogel, Roxane Bowden, Mihaela Glamoclija, Zhisheng Zhang, and Stephen M. Elardo. Unique Meteorite from Early Amazonian Mars: Water-Rich Basaltic Breccia Northwest Africa 7034. Science, Jan 3, 2013 DOI: 10.1126/science.1228858

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Spinal ultrasounds seeking why astronauts grow taller in space

  • PDF

The body navigator portion of the Just-In-Time tool reveals the internal anatomy structure as the user moves the mouse over an area of the body image. By allowing the user to see below the skin surface, they can identify the region of interest and correctly orient the ultrasound imaging transducer. (Credit: Image courtesy of Scott A. Dulchavsky)

Jan. 3, 2013 — Did you ever wish you could be just a teensy bit taller? Well, if you spend a few months in space, you could get your wish -- temporarily. It is a commonly known fact that astronauts living aboard the International Space Station grow up to 3 percent taller while living in microgravity. They return to their normal height when back on Earth. Studying the impact of this change on the spine and advancing medical imaging technologies are the goals of the Spinal Ultrasound investigation.

"This is the very first time that spinal ultrasound will be used to evaluate the changes in the spine," said Scott A. Dulchavsky, M.D., Ph.D., principal investigator for the station study. "Spinal ultrasound is more challenging to perform than many of the previous ultrasound examinations done in space."

Part of the difficulty with imaging the spine is quite simply human anatomy. Using Ultrasound 2, the machine aboard station as a facility for human health studies, astronauts have an advanced tool to view the inner workings of their bodies.

"Today there is a new ultrasound device on the station that allows more precise musculoskeletal imaging required for assessment of the complex anatomy and the spine," Dulchavsky said. "The crew will be able to perform these complex evaluations in the next year due to a newly developed Just-In-Time training guide for spinal ultrasound, combined with refinements in crew training and remote guidance procedures."

The research could help with developing exercises for better crew health and guiding improved rehabilitation techniques when astronauts return to Earth. Understanding how changes to the spine occur in real-time response to life in space also will help crews prepare for future long-duration missions.

Another benefit of this research is that spinal ultrasound could gain clinical acceptance on the ground for medical testing. Dulchavsky points out that this shift could reduce costs and provide a safer imaging option for patients.

"Ultrasound also allows us to evaluate physiology in motion, such as the movement of muscles, blood in vessels, and function in other systems in the body," said Dulchavsky. "Physiologic parameters derived from ultrasound and Doppler give instantaneous observations about the body non-invasively without radiation."

Six crew members will serve as test subjects for these spinal ultrasound scans. The data sessions are scheduled to take place on orbit starting in January 2013. An astronaut will scan the spinal area of a fellow crew member at 30, 90, and 150 days into flight. Researchers will watch in real time from the ground via streaming video downlinks. Ultrasound images will focus on the cervical and lumbar areas of the spine and surrounding tissues. The test subjects will also undergo pre- and post-flight ultrasound and MRI scans on Earth to provide baseline data.

Ultrasound technology is convenient for use not only in space, but also here on Earth. Due to the portability of the machines, the rapid training methods developed by NASA researchers and the repeatability, ultrasound can offer an inexpensive and scalable alternative to MRIs for healthcare needs. Medical personnel already make use of the training methods developed for the space station crews when using ultrasound in remote areas.

"This technique in spinal ultrasound may someday serve as a clinical data source where standard MRI imaging is not available, even if this seems ambitious," Dulchavsky said. "The vast majority of the global population has no access to an MRI. The in-flight tools such as the interactive Spinal Ultrasound guide can also be used to train other complex procedures, albeit medical or otherwise."

So just why do astronauts get taller in space? Researchers are hoping this study will help answer that question, while also growing medical knowledge of the spine and improving ultrasound methods and procedures.


Story Source:

The above story is reprinted from materials provided by NASA.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of NewsAstronomy or its staff.

Quadrantids create year's first meteor shower

  • PDF

False-color image of a rare early Quadrantid, captured by a NASA meteor camera in 2010. (Credit: NASA/MSFC)

Jan. 2, 2013 — A little-known meteor shower named after an extinct constellation, the Quadrantids will present an excellent chance for hardy souls to start the year off with some late-night meteor watching. Peaking in the wee morning hours of Jan. 3, the Quadrantids have a maximum rate of about 80 per hour, varying between 60-200. Unfortunately, light from a waning gibbous moon will wash out many Quadrantids, cutting down on the number of meteors seen by skywatchers.

Unlike the more famous Perseid and Geminid meteor showers, the Quadrantids only last a few hours, so it's the morning of Jan. 3 or nothing. Given the location of the radiant -- northern tip of Bootes the Herdsman -- only observers at latitudes north of 51 degrees south will be able to see Quadrantids.

Watch the Quadrantids! Live Ustream Feed

A live Ustream feed of the Quadrantid shower will be embedded below on the nights of Jan. 2-4 (http://www.ustream.tv/channel/nasa-msfc). The camera is mounted at NASA's Marshall Space Flight Center in Huntsville, Ala. During the day you will see either pre-recorded footage or a blank box -- the camera is light-activated and turns on at dusk (approx. 6 p.m. EST). › Convert to your local time: http://ssd.jpl.nasa.gov/tc.cgi

Do You Have Some Great Quadrantid Images?

If you have some great images of the Quadrantid meteor shower, please consider adding them to the Quadrantid Meteors photo group in Flickr (http://www.flickr.com/groups/quadrantids/). Who knows -- your images may attract interest from the media and receive international exposure.

More About the Quadrantids

The Quadrantids derive their name from the constellation of Quadrans Muralis (mural quadrant), which was created by the French astronomer Jerome Lalande in 1795. Located between the constellations of Bootes and Draco, Quadrans represents an early astronomical instrument used to observe and plot stars. Even though the constellation is no longer recognized by astronomers, it was around long enough to give the meteor shower -- first seen in 1825 -- its name.

Like the Geminids, the Quadrantids originate from an asteroid, called 2003 EH1. Dynamical studies suggest that this body could very well be a piece of a comet which broke apart several centuries ago, and that the meteors you will see before dawn on Jan. 3 are the small debris from this fragmentation. After hundreds of years orbiting the sun, they will enter our atmosphere at 90,000 mph, burning up 50 miles above Earth's surface -- a fiery end to a long journey!

Editor's note, Jan. 2, 10:45 a.m. EST: Tonight is the peak of the 2013 Quadrantid meteor shower. Best viewing will be in the northern hemisphere, but the shower can be seen at latitudes north of 51 degrees south. Meteor rates increase after midnight and peak between 3 a.m. and dawn, your local time. To view Quadrantids, go outside and allow your eyes 30-45 minutes to adjust to the dark. Look straight up, allowing your eyes to take in as much of the sky as possible. You will need cloudless, dark skies away from city lights to see the shower. The maximum rate will be about 120/hour. However, light from the waning gibbous moon will wash out fainter meteors, so don't expect to see this many. The peak rate of the Quadrantids has varied between 60-200, so its peak is not as consistent as other showers.


Story Source:

The above story is reprinted from materials provided by NASA.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

NASA puts Orion backup parachutes to the test

  • PDF

A mockup Orion capsule is poised to drop from a plane 25,000 feet above the U.S. Army Yuma Proving Ground in Arizona to test the parachute design for the spacecraft that will take humans farther than they’ve ever been before – and return them to Earth at greater speeds than ever before. (Credit: NASA)

Dec. 20, 2012 — NASA completed the latest in a series of parachute tests for its Orion spacecraft Thursday at the U.S. Army Yuma Proving Ground in southwestern Arizona, marking another step toward a first flight test in 2014. The test verified Orion can land safely even if one of its two drogue parachutes does not open during descent.

Orion will take humans farther into space than ever before, but one of the most challenging things the multipurpose vehicle will do is bring its crew home safely. Because it will return from greater distances, Orion will reenter Earth's atmosphere at speeds of more than 20,000 mph. After re-entry, the parachutes are all that will lower the capsule carrying astronauts back to Earth.

"The mockup vehicle landed safely in the desert and everything went as planned," said Chris Johnson, a NASA project manager for Orion's parachute assembly system. "We designed the parachute system so nothing will go wrong, but plan and test as though something will so we can make sure Orion is the safest vehicle ever to take humans to space."

Orion uses five parachutes. Three are main parachutes measuring 116 feet wide and two are drogue parachutes measuring 23 feet wide. The 21,000-pound capsule needs only two main parachutes and one drogue. The extra two provide a backup in case one of the primary parachutes fails.

To verify Orion could land safely with only one drogue parachute, engineers dropped a spacecraft mockup from a plane 25,000 feet above the Arizona desert and simulated a failure of one of the drogues. About 30 seconds into the mockup's fall, the second drogue parachute opened and slowed the mockup down enough for the three main parachutes to take over the descent.

The next Orion parachute test is scheduled for February and will simulate a failure of one of the three main parachutes.

In 2014, an uncrewed Orion spacecraft will launch from Cape Canaveral Air Force Station in Florida on Exploration Flight Test-1. The spacecraft will travel 3,600 miles above Earth's surface. This is 15 times farther than the International Space Station's orbit and farther than any spacecraft designed to carry humans has gone in more than 40 years. The main flight objective is to test Orion's heat shield performance at speeds generated during a return from deep space.

For information about Orion, visit: http://www.nasa.gov/orion


Story Source:

The above story is reprinted from materials provided by NASA.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Clays on Mars: More plentiful than expected

  • PDF

Water-ice clouds, polar ice, polar regions, and geological features can be seen in this full-disk image of Mars. (Credit: NASA/JPL)

Dec. 20, 2012 — A new study co-authored by the Georgia Institute of Technology indicates that clay minerals, rocks that usually form when water is present for long periods of time, cover a larger portion of Mars than previously thought. In fact, Assistant Professor James Wray and the research team say clays were in some of the rocks studied by Opportunity when it landed at Eagle crater in 2004. The rover only detected acidic sulfates and has since driven about 22 miles to Endeavour Crater, an area of the planet Wray pinpointed for clays in 2009.

The study is published online in the current edition of Geophysical Research Letters.

The project, which was led by Eldar Noe Dobrea of the Planetary Science Institute, identified the clay minerals using a spectroscopic analysis from the Mars Reconnaissance Orbiter. The research shows that clays also exist in the Meridiani plains that Opportunity rolled over as it trekked toward its current position.

"It's not a surprise that Opportunity didn't find clays while exploring," said Wray, a faculty member in the School of Earth and Atmospheric Sciences. "We didn't know they existed on Mars until after the rover arrived. Opportunity doesn't have the same tools that have proven so effective for detecting clays from orbit."

The clay signatures near Eagle crater are very weak, especially compared to those along the rim and inside Endeavour crater. Wray believes clays could have been more plentiful in the past, but Mars' volcanic, acidic history has probably eliminated some of them.

"It was also surprising to find clays in geologically younger terrain than the sulfates," said Dobrea. Current theories of Martian geological history suggest that clays, a product of aqueous alteration, actually formed early on when the planet's waters were more alkaline. As the water acidified due to volcanism, the dominant alteration mineralogy became sulfates. "This forces us to rethink our current hypotheses of the history of water on Mars," he added.

Even though Opportunity has reached an area believed to contain rich clay deposits, the odds are still stacked against it. Opportunity was supposed to survive for only three months. It's still going strong nine years later, but the rover's two mineralogical instruments don't work anymore. Instead, Opportunity must take pictures of rocks with its panoramic camera and analyze targets with a spectrometer to try and determine the composition of rock layers.

"So far, we've only been able to identify areas of clay deposits from orbit," said Wray. "If Opportunity can find a sample and give us a closer look, we should be able to determine how the rock was formed, such as in a deep lake, shallow pond or volcanic system."

As for the other rover on the other side of Mars, Curiosity's instruments are better equipped to search for signs of past or current conditions for habitable life, thanks in part to Opportunity. Wray is a member of Curiosity's science team.


Story Source:

The above story is reprinted from materials provided by Georgia Institute of Technology.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. E. Z. Noe Dobrea, J. J. Wray, F. J. Calef, T. J. Parker, S. L. Murchie. Hydrated minerals on Endeavour Crater's rim and interior, and surrounding plains: New insights from CRISM data. Geophysical Research Letters, 2012; 39 (23) DOI: 10.1029/2012GL053180

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Meteorite triggered scientific 'Gold Rush'

  • PDF

Geology professor Qing-zhu Yin holds a fragment of the meteorite that exploded over the Sierra foothills this past spring. (Credit: Gregory Urquiaga/UC Davis photo)

Dec. 20, 2012 — A meteorite that exploded as a fireball over California's Sierra foothills this past spring was among the fastest, rarest meteorites known to have hit Earth, and it traveled a highly eccentric orbital route to get here.

An international team of scientists presents these and other findings in a study published Dec. 21, in the journal Science. The 70-member team included nine researchers from UC Davis, along with scientists from the SETI Institute, NASA and other institutions.

The researchers found that the meteorite that fell over Northern California on April 22 was the rarest type known to have hit Earth -- a carbonaceous chondrite. It is composed of cosmic dust and presolar materials that helped form the planets of the solar system.

The scientists learned that the meteorite formed about 4.5 billion years ago. It was knocked off its parent body, which may have been an asteroid or a Jupiter-family comet, roughly 50,000 years ago. That began its journey to Sutter's Mill, the gold discovery site that sparked the California Gold Rush.

As it flew toward Earth, it traveled an eccentric course through the solar system, flying from an orbit close to Jupiter toward the sun, passing by Mercury and Venus, and then flying out to hit Earth.

The high-speed, minivan-sized meteorite entered the atmosphere at about 64,000 miles per hour. The study said it was the fastest, "most energetic" reported meteorite that's fallen since 2008, when an asteroid fell over Sudan.

"If this were a much bigger object, it could have been a disaster," said co-author and UC Davis geology professor Qing-zhu Yin. "This is a happy story in this case. "

Before entering Earth's atmosphere, the meteorite is estimated to have weighed roughly 100,000 pounds. Most of that mass burned away when the meteorite exploded. Scientists and private collectors have recovered about 2 pounds remaining.

UC Davis is 60 miles west of the El Dorado county towns of Coloma and Lotus, where pieces of the meteorite were found on residents' driveways and in local forests and parks.

When the meteorite fell, Yin, whose lab contains some of the country's most specialized equipment to measure the age and composition of meteorites, searched for and collected pieces of the fallen meteorite with students and volunteers. He also led a 35-member subgroup of international researchers to study and share information about the meteorite's mineralogy, internal textures, chemical and isotopic compositions and magnetic properties.

Meteorites like Sutter's Mill are thought to have delivered oceans of water to Earth early in its history. Using neutron-computed tomography, UC Davis researchers helped identify where hydrogen, and therefore water-rich fragments, resides in the meteorite without breaking it open.

For the first time, the Doppler weather radar network helped track the falling carbonaceous chondrite meteorite pieces, aiding scientists in the quick recovery of them, the study reports. Yin expects that the weather radar data in the public domain could greatly enhance and benefit future meteorite recoveries on land.

"For me, the fun of this scientific gold rush is really just beginning," said Yin. "This first report based on the initial findings provides a platform to propel us into more detailed research. Scientists are still finding new and exciting things in Murchison, a similar type of meteorite to Sutter's Mill, which fell in Victoria, Australia, in 1969, the same year Apollo astronauts Neil Armstrong and Buzz Aldrin returned the first lunar samples to the Earth. We will learn a lot more with Sutter's Mill."


Story Source:

The above story is reprinted from materials provided by University of California - Davis.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. P. Jenniskens, M. D. Fries, Q.-Z. Yin, M. Zolensky, A. N. Krot, S. A. Sandford, D. Sears, R. Beauford, D. S. Ebel, J. M. Friedrich, K. Nagashima, J. Wimpenny, A. Yamakawa, K. Nishiizumi, Y. Hamajima, M. W. Caffee, K. C. Welten, M. Laubenstein, A. M. Davis, S. B. Simon, P. R. Heck, E. D. Young, I. E. Kohl, M. H. Thiemens, M. H. Nunn, T. Mikouchi, K. Hagiya, K. Ohsumi, T. A. Cahill, J. A. Lawton, D. Barnes, A. Steele, P. Rochette, K. L. Verosub, J. Gattacceca, G. Cooper, D. P. Glavin, A. S. Burton, J. P. Dworkin, J. E. Elsila, S. Pizzarello, R. Ogliore, P. Schmitt-Kopplin, M. Harir, N. Hertkorn, A. Verchovsky, M. Grady, K. Nagao, R. Okazaki, H. Takechi, T. Hiroi, K. Smith, E. A. Silber, P. G. Brown, J. Albers, D. Klotz, M. Hankey, R. Matson, J. A. Fries, R. J. Walker, I. Puchtel, C.-T. A. Lee, M. E. Erdman, G. R. Eppich, S. Roeske, Z. Gabelica, M. Lerche, M. Nuevo, B. Girten, S. P. Worden. Radar-Enabled Recovery of the Sutter's Mill Meteorite, a Carbonaceous Chondrite Regolith Breccia. Science, 2012; 338 (6114): 1583 DOI: 10.1126/science.1227163

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

New meteorite suggests that asteroid surfaces more complex than previously thought

  • PDF

These are some of the 77 fragments of the Sutter’s Mill meteorite fall that were collected in April 2012. (Credit: NASA/E. James)

Dec. 20, 2012 — Meteorites that had fallen from an asteroid impact that lit up the skies over California and Nevada in April are showing scientists just how complex an asteroid surface can be. A new study published in Science this week by an international team of researchers describes the speedy recovery of the meteorites and reports that this space rock is an unusual example from a rare group known as carbonaceous chondrites, which contain some of the oldest material in the solar system. The study of these meteorites and others like them could hold answers to unsolved mysteries about the origin of life on Earth as they contain molecules such as water and amino acids.

"We found that this meteorite is a 'breccia,' a mixture of different rocks that accumulated at the surface of a larger asteroid, and those surfaces can be more diverse than we thought before," said co-author Denton Ebel, chair of the Division of Physical Sciences at the American Museum of Natural History.

About eight months ago, several Doppler weather radars detected a hail of rocks following a fireball traveling at a record-breaking 28.6 kilometers per second (about 64,000 miles per hour) over the Sierra Nevada in northern California. An immediate search-and-recover mission, led by NASA Ames Research Center, the SETI Institute, and the University of California, Davis, resulted in the retrieval of 77 meteorites. The fragments, which were in pristine shape despite entering the atmosphere at a speed twice as fast as a typical meteorite fall, were collectively called the Sutter's Mill meteorite after the nearby historical site that started the California Gold Rush.

"From the loud sonic boom, we quickly realized that this was an asteroid several meters in size, the biggest object to hit over land since the impact of asteroid 2008 TC3 in the north of Sudan in 2008," said lead author and meteor astronomer Peter Jenniskens of NASA Ames and SETI. "That asteroid proved to be a mixed bag of different types of meteorites, and we realized it would be very interesting to find out how diverse the Sutter's Mill meteorites were."

Several fragments were sent to laboratories around the world for simultaneous analysis of the meteorite's mineralogy and structure. The Sutter's Mill meteorite was classified as a CM chondrite, C standing for carbonaceous -- high in carbon content -- and M standing for the group's type specimen, the Mighei meteorite that fell in Ukraine in the late 1800s.

Ebel received five Sutter's Mill meteorites to study using x-ray computed tomography (CT), an imaging technique that takes pictures of the inside of a specimen without destroying it. The Museum's scanner takes more than 1,000 x-ray images of the object as it rotates inside of the machine. The data collected from these x-rays are then converted by computers to form a 3-D image of the specimen's interior, one slice at a time, to understand the components of the meteorite.

"In the same way that medical tomography, called CAT scanning, is used to image the interior of the human body, CT scanning in a research laboratory allows us to obtain images of the interiors of solid objects, but with a much higher resolution," Ebel said. "This is a fundamentally important tool not just for looking at rocks but for curating them and figuring out whether anything interesting is inside."

CT scans at the Museum, and at the University of California, Davis in an effort led by cosmochemist Qing-Zhu Yin, revealed that no two Sutter's Mill meteorites are the same. The meteorites contained angular pieces of different composition and density. They showed diversity on millimeter scale.

"This was the first time that a CM chondrite was found to be clearly a breccia," Yin said. "The rocky fragments came together following impacts on the parent asteroid, which implies that this meteorite originated from near its surface."

Analyses performed using different techniques at other institutions were in agreement: the mineralogy and other geochemical features of these fragments are unexpectedly diverse and complex. This suggests that the surface of the asteroid that spawned the CM chondrites, their "parent body," is more complex than previously thought.

"This meteorite is special because it records many collisional processes and mixing that we, oddly, don't see very often," Ebel said. "Maybe the real question is 'why don't we see more of this?' It could be that most of the samples we've worked with in the past didn't hold up very well as they entered the atmosphere. Or that we're just seeing a small segment of what's really out there because we don't have meteorite records of what fell to the Earth thousands or millions of years ago. We still have a lot of work to do to figure out what's really going on in the asteroid belt."


Story Source:

The above story is reprinted from materials provided by American Museum of Natural History.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. P. Jenniskens, M. D. Fries, Q.-Z. Yin, M. Zolensky, A. N. Krot, S. A. Sandford, D. Sears, R. Beauford, D. S. Ebel, J. M. Friedrich, K. Nagashima, J. Wimpenny, A. Yamakawa, K. Nishiizumi, Y. Hamajima, M. W. Caffee, K. C. Welten, M. Laubenstein, A. M. Davis, S. B. Simon, P. R. Heck, E. D. Young, I. E. Kohl, M. H. Thiemens, M. H. Nunn, T. Mikouchi, K. Hagiya, K. Ohsumi, T. A. Cahill, J. A. Lawton, D. Barnes, A. Steele, P. Rochette, K. L. Verosub, J. Gattacceca, G. Cooper, D. P. Glavin, A. S. Burton, J. P. Dworkin, J. E. Elsila, S. Pizzarello, R. Ogliore, P. Schmitt-Kopplin, M. Harir, N. Hertkorn, A. Verchovsky, M. Grady, K. Nagao, R. Okazaki, H. Takechi, T. Hiroi, K. Smith, E. A. Silber, P. G. Brown, J. Albers, D. Klotz, M. Hankey, R. Matson, J. A. Fries, R. J. Walker, I. Puchtel, C.-T. A. Lee, M. E. Erdman, G. R. Eppich, S. Roeske, Z. Gabelica, M. Lerche, M. Nuevo, B. Girten, S. P. Worden. Radar-Enabled Recovery of the Sutter's Mill Meteorite, a Carbonaceous Chondrite Regolith Breccia. Science, 2012; 338 (6114): 1583 DOI: 10.1126/science.1227163

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Asteroid Toutatis slowly tumbles by Earth

  • PDF

Radar imagery of asteroid Toutatis taken by NASA's Goldstone Solar System Radar on Dec. 12 and 13, 2012. (Credit: NASA/JPL-Caltech)

Dec. 16, 2012 — Scientists working with NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, Calif., have generated a series of radar data images of a three-mile-long (4.8-kilometer) asteroid that made its closest approach to Earth on Dec. 12, 2012.

The radar data images of asteroid Toutatis have been assembled into a short movie, available online at: http://www.jpl.nasa.gov/video/index.php?id=1175 .

The images that make up the movie clip were generated with data taken on Dec. 12 and 13, 2012. On Dec. 12, the day of its closest approach to Earth, Toutatis was about 18 lunar distances, 4.3 million miles (6.9 million kilometers) from Earth. On Dec. 13, the asteroid was about 4.4 million miles (7 million kilometers), or about 18.2 lunar distances.

The radar data images of asteroid Toutatis indicate that it is an elongated, irregularly shaped object with ridges and perhaps craters. Along with shape detail, scientists are also seeing some interesting bright glints that could be surface boulders. Toutatis has a very slow, tumbling rotational state. The asteroid rotates about its long axis every 5.4 days and precesses (changes the orientation of its rotational axis) like a wobbling, badly thrown football, every 7.4 days.

The orbit of Toutatis is well understood. The next time Toutatis will approach at least this close to Earth is in November of 2069, when the asteroid will safely fly by at about 7.7 lunar distances, or 1.8 million miles (3 million kilometers). An analysis indicates there is zero possibility of an Earth impact over the entire interval over which its motion can be accurately computed, which is about the next four centuries.

This radar data imagery will help scientists improve their understanding of the asteroid's spin state, which will also help them understand its interior.

The resolution in the image frames is 12 feet (3.75 meters) per pixel.

NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and plots their orbits to determine if any could be potentially hazardous to our planet.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Mariner 2's encounter with Venus: NASA celebrates 50 years of planetary exploration

  • PDF

Mariner 2 was the world's first successful interplanetary spacecraft. Launched August 27, 1962, on an Atlas-Agena rocket, Mariner 2 passed within about 34,000 kilometers (21,000 miles) of Venus, sending back valuable new information about interplanetary space and the Venusian atmosphere. (Credit: NASA/JPL)

Dec. 12, 2012 — Fifty years ago on a mid-December day, NASA's Mariner 2 spacecraft sailed close to the shrouded planet Venus, marking the first time any spacecraft had ever successfully made a close-up study of another planet. The flyby, 36 million miles (58 million kilometers) away from Earth, gave America its first bona fide space "first" after five years in which the Soviet Union led with several space exploration milestones. Designed and built by NASA's Jet Propulsion Laboratory in Pasadena, Calif., the successful Mariner 2 spacecraft ushered in a new era of solar system exploration.

"JPL has always attempted to do mighty things on behalf of NASA and our nation," said JPL director Charles Elachi. "Achieving America's first 'first in space' is among the lab's proudest achievements."

In celebration of the anniversary, an interactive presentation highlighting 50 years of planetary exploration is available online at: http://www.jpl.nasa.gov/50years .

The first Mariners were designed and built on an extremely demanding schedule. JPL had to ready three probes -- two to fly to Venus and one spare -- in less than a year, with strict weight limits.

Getting to Venus was no easy feat. The Soviet Union suffered several failures in their attempts to get to Venus in 1961. And the rocket carrying NASA's first attempt, Mariner 1, began to fishtail shortly after launch. The range safety officer pushed the self-destruct button four minutes and 53 seconds into flight.

Mariner 2 was launched Aug. 27, 1962, from Cape Canaveral. Shortly after liftoff, the rocket began to roll, making it unable to respond to guidance commands. In the first of a series of Mariner "miracles," the electrical short causing the issue mysteriously healed itself after about a minute.

En route to Venus, Mariner 2 encountered many problems that nearly ended its mission. Among these were a solar panel that twice stopped working, a balky sensor designed to locate Earth and gyros that mysteriously misbehaved. Most troubling of all, temperatures on the spacecraft climbed to alarming levels as Mariner 2 drew closer to Venus. Mission controllers worried the spacecraft might cook itself before reaching its destination.

But on Dec. 14, 1962, Mariner 2 hit its expected mark, gliding within 21,564 miles (13,399 kilometers) of our closest planetary neighbor. Machines at JPL spit out rolls of paper tape with microwave, infrared, radiation and magnetic fields data.

The encounter produced the first close-up measurements of Venus's scorching surface temperature, helping to confirm scientists' hypotheses of a runaway "greenhouse" effect that trapped heat from the sun under an atmospheric blanket. The spacecraft's precision tracking also enabled navigators to use radio signals to measure the effect of Venus's gravity on the spacecraft and calculate the most precise figure ever of the planet's mass.

The mission also made scientific discoveries beyond Venus. During Mariner 2's cruise phase, it was the first to confirm the existence of the solar wind, the stream of charged particles flowing outward from the sun. Its data also enabled scientists to refine the value for an astronomical unit, the average distance between Earth and the sun. Mariner 2 also showed that micrometeorites and the radiation environment were not significant threats in that part of the solar system.

Mariner 2 was a thrilling success during the early, uncertain days of space exploration. As Mariner 2's project manager Jack James of JPL reflected before his death in 2001, "There will be other missions to Venus, but there will never be another first mission to Venus."

Six other successful Mariner missions to Venus, Mars and Mercury followed. And in the ensuing decades, NASA sent spacecraft to all the planets, as well as comets, asteroids and other unfamiliar worlds in our solar system.

For a fuller history of Mariner 2's visit of Venus: visit http://www.jpl.nasa.gov/mariner2/ .

JPL is managed for NASA by the California Institute of Technology, Pasadena.


Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Cassini spots mini Nile River on Saturn's moon Titan

  • PDF

This image from NASA's Cassini spacecraft shows a vast river system on Saturn's moon Titan. It is the first time images from space have revealed a river system so vast and in such high resolution anywhere other than Earth. (Credit: NASA/JPL-Caltech/ASI)

Dec. 12, 2012 — Scientists with NASA's Cassini mission have spotted what appears to be a miniature, extraterrestrial likeness of Earth's Nile River: a river valley on Saturn's moon Titan that stretches more than 200 miles (400 kilometers) from its "headwaters" to a large sea. It is the first time images have revealed a river system this vast and in such high resolution anywhere other than Earth.

Scientists deduce that the river, which is in Titan's north polar region, is filled with liquid hydrocarbons because it appears dark along its entire length in the high-resolution radar image, indicating a smooth surface.

"Though there are some short, local meanders, the relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers running into the southern margin of this same Titan sea," said Jani Radebaugh, a Cassini radar team associate at Brigham Young University, Provo, Utah. "Such faults -- fractures in Titan's bedrock -- may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves."

The new image is available online at: http://www.nasa.gov/mission_pages/cassini/multimedia/pia16197.html .

Titan is the only other world we know of that has stable liquid on its surface. While Earth's hydrologic cycle relies on water, Titan's equivalent cycle involves hydrocarbons such as ethane and methane. In Titan's equatorial regions, images from Cassini's visible-light cameras in late 2010 revealed regions that darkened due to recent rainfall. Cassini's visual and infrared mapping spectrometer confirmed liquid ethane at a lake in Titan's southern hemisphere known as Ontario Lacus in 2008.

"Titan is the only place we've found besides Earth that has a liquid in continuous movement on its surface," said Steve Wall, the radar deputy team lead, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This picture gives us a snapshot of a world in motion. Rain falls, and rivers move that rain to lakes and seas, where evaporation starts the cycle all over again. On Earth, the liquid is water; on Titan, it's methane; but on both it affects most everything that happens."

The radar image here was taken on Sept. 26, 2012. It shows Titan's north polar region, where the river valley flows into Kraken Mare, a sea that is, in terms of size, between the Caspian Sea and the Mediterranean Sea on Earth. The real Nile River stretches about 4,100 miles (6,700 kilometers). The processes that led to the formation of Earth's Nile are complex, but involve faulting in some regions.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. NASA's 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 was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the US and several European countries. JPL is a division of the California Institute of Technology in Pasadena.


Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Geminid meteors set to light up winter sky

  • PDF

An all-sky image of the 2004 Geminids meteor shower. (Credit: Chris L. Peterson, Cloudbait Observatory)

Dec. 12, 2012 — On the evening of December 13 and the morning of 14 December, skywatchers across the world will be looking up as the Geminid meteor shower reaches its peak, in potentially one of the best night sky events of the year.

At its peak and in a clear, dark sky tens of 'shooting stars' or meteors may be visible each hour. Meteors are the result of small particles entering Earth's atmosphere at high speed, burning up and super-heating the air around them, which then shines as a characteristic short-lived streak of light. In this case the debris is associated with the asteroidal object 3200 Phaethon, which many astronomers believe to be an extinct comet.

The meteors appear to originate from a 'radiant' in the constellation of Gemini, hence the name Geminid. By 0200 GMT on 14 December the radiant will be almost overhead from the UK, making it ideally placed for observers. As a bonus, the Moon will not be present in the sky on the morning of maximum activity so the prospects for a good view of the shower are excellent. And unlike many astronomical phenomena, meteors are best seen without a telescope (and are also perfectly safe to watch).

Meteors in the Geminid shower are less well known than those at other times of year, probably because the weather in December is less reliable. But those who brave the cold can be rewarded with a fine view. In comparison with other showers, Geminid meteors travel fairly slowly, at around 35 km (22 miles) per second, are bright and have a yellowish hue, making them distinct and easy to spot.

According to the International Meteor Organisation, which coordinates meteor observations, the Geminids meteor shower will peak at around 2330 GMT on 13 December, but the highest level activity is spread over a period lasting a day or more. This means that if conditions are clear even casual observers may want to take a look until Saturday morning.


Story Source:

The above story is reprinted from materials provided by Royal Astronomical Society (RAS).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Grains gang up to bear brunt of missile and meteorite impacts

  • PDF

The way a meteorite or missile transfers the energy of its impact to sand and dirt grains is far more complex than scientists thought. (Credit: Impact illustration courtesy of NASA)

Dec. 11, 2012 — High-speed video of projectiles slamming into a bed of disks has given scientists a new microscopic picture of the way a meteorite or missile transfers the energy of its impact to sand and dirt grains.

The transfer is jerky, not smooth. "It was surprising just how unsmooth the slow-down of the intruding object was," Duke physicist Robert Behringer said. His team describes their new videos and impact analysis in the Dec. 7 Physical Review Letters. The research may change the way scientists model meteorite and missile impacts and their effects.

Scientists previously assumed that the slowing down would be smooth and that any sound wave would travel through a granular material in a regular, uniform pattern, similar to the way noise from a clap of the hands diffuses evenly in all directions through the air. But using high-speed video, Behringer, his graduate student Abram Clark and Lou Kondic of the New Jersey Institute of Technology have shown a very different behavior for the sound wave and grains during a collision.

In the study, supported by the Defense Threat Reduction Agency, the team shot bronze disks into a narrow bed of photoelastic grains and used an ultrafast camera to track the collision energy as it shifted from the disk to the beads. The footage shows that the bronze disk loses most of its energy in intense, sporadic acoustic pulses along networks of grains, or force chains, in the bed of beads.

"This phenomenon was so hard to observe before because of how fast the force chains travel," Behringer said. The standard movie rate is about 30 frames per second. To capture the path of energy down the force chains, the scientists had to use a camera that could capture 40,000 frames per second, 1300 times faster than a normal video, because the sound pulses move at such high speeds.

The scientists shot the intruding disks into the photoelastic grains at speeds up to 6.5 meters per second, about 15 miles per hour. On impact, the force chains in the disks started moving the energy away from the intruding object, dumping it down deep in the bed of disks like the drainpipes of a septic system carrying water and waste away from a house, Behringer said.

The speed of the bronze disk was well under sonic or super-sonic speed, which could make the patterns of energy transfer substantially different, the team noted in the paper. "For supersonic speeds, it's kind of like the car chases that happen in markets in movies. People can't get out of the way fast enough. Similarly the pulses wouldn't clear the chain networks and the forces would back up rather than get carried away from the intruder," Behringer said.

Studying the impacts at sonic and supersonic speeds, however, is a set of experiments that requires different grain particles, Behringer said, adding it's one the team may try soon. He also explained that once a missile or meteor drops below sonic speeds, the grains absorbing its impact would carry the energy and momentum away jerkily and sporadically, just as the team's new microscopic picture shows.


Story Source:

The above story is reprinted from materials provided by Duke University. The original article was written by Ashley Yeager.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Clark, A., Kondic, L., and Behringer, R. Particle Scale Dynamics in Granular Impact. Physical Review Letters, 2012 DOI: 10.1103/Physics.5.137

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

What is creating gullies on giant asteroid Vesta?

  • PDF

This image shows examples of long, narrow, sinuous gullies that scientists on NASA's Dawn mission have found on the giant asteroid Vesta. (Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Dec. 6, 2012 — In a preliminary analysis of images from NASA's Dawn mission, scientists have spotted intriguing gullies that sculpt the walls of geologically young craters on the giant asteroid Vesta. Led by Jennifer Scully, a Dawn team member at the University of California, Los Angeles, these scientists have found narrow channels of two types in images from Dawn's framing camera -- some that look like straight chutes and others that carve more sinuous trails and end in lobe-shaped deposits. The mystery, however, is what is creating them?

The presentation on gullies is one of several that Dawn team members are making at this year's American Geophysical Union conference in San Francisco. Other topics include craters on Vesta, the giant asteroid's mineralogy, and the distinctive dark and bright materials found on the surface.

"The straight gullies we see on Vesta are textbook examples of flows of dry material, like sand, that we've seen on Earth's moon and we expected to see on Vesta," said Scully, who presented in-progress findings on these gullies today. "But these sinuous gullies are an exciting, unexpected find that we are still trying to understand."

The sinuous gullies are longer, narrower, and curvier than the short, wide, straight gullies. They tend to start from V-shaped, collapsed regions described as "alcoves" and merge with other gullies. Scientists think different processes formed the two types of gullies and have been looking at images of Earth, Mars and other small bodies for clues.

"On Earth, similar features -- seen at places like Meteor Crater in Arizona -- are carved by liquid water," said Christopher Russell, Dawn's principal investigator, also based at UCLA. "On Mars, there is still a debate about what has caused them. We need to analyze the Vesta gullies very carefully before definitively specifying their source."

Indeed, scientists have suggested various explanations for gullies on Mars since fresh-looking gullies were discovered in images from NASA's Mars Global Surveyor in 2000. Some of the proposed Martian mechanisms involve water, some carbon dioxide, and some neither. One study in 2010 suggested that carbon-dioxide frost was causing fresh flows of sand on the Red Planet.

JPL manages the Dawn mission for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. The University of California at Los Angeles (UCLA) is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team. The California Institute of Technology in Pasadena manages JPL for NASA. For more information about Dawn, visit: http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov .


Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.

Sungrazing comets as solar probes

  • PDF

On Dec. 15, 2011, NASA's Solar Dynamics Observatory captured footage of Comet Lovejoy approaching the sun. The images and data collected by NASA's solar observing fleet can help scientists learn more about the sun itself. (Credit: NASA/Goddard Scientific Visual Studio)

NewsAstronomy (Dec. 6, 2012) — To observe how winds move high in Earth's atmosphere, scientists sometimes release clouds of barium as tracers to track how the material corkscrews, blows around, and changes composition in response to high altitude winds -- but scientists have no similar technique to study the turbulent atmosphere of the sun.

So researchers were excited in December 2011, when Comet Lovejoy swept right through the sun's corona with its long tail streaming behind it. Several missions -- including NASA's Solar Dynamics Observatory (SDO), NASA's Solar and Terrestrial Relations Observatory (STEREO), ESA/NASA's Solar and Heliospheric Observatory (SOHO) and the JAXA/NASA mission Hinode -- captured images of the comet, showing how its long tail was buffeted by systems around the sun, offering scientists a unique way of observing movement as if they'd orchestrated the experiment themselves.

This unexpected set of observations captured the attention of scientists, bringing two research communities together: comet researchers who can use solar observations for their studies and solar scientists can use comet observations to study the sun.

Scientists recently shared their results at the 2012 Fall American Geophysical Union meeting in San Francisco, Calif., and how the comet helped highlight the intensely dynamic environment in the sun's atmosphere, the corona. Since comet tails are rapidly ionized by losing electrons in that hot environment, their movement is affected by the sun's magnetic field. Thus the tail's path can act as a tracer of the complex magnetic system higher up in the corona. Understanding such magnetic systems is a crucial part of space weather research and the study of how magnetic energy is converted to giant explosions on the sun such as solar flares or coronal mass ejections.

Comet Lovejoy is a kind of comet known as a sungrazer, which swings particularly close to the sun. Since SOHO launched in1995, it has shown us thousands more sungrazer comets than any tool ever has before -- almost 2,400 comets as of November 2012. Because we are in a period of high sun grazing comet activity, scientist's can expect many more chances to watch these natural research satellites in the coming years. Another large comet is expected to have a close solar pass on November 21, 2013. This comet is roughly the size of Hale-Bopp, so it should give quite a show.


Story Source:

The above story is reprinted from materials provided by NASA.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of NewsAstronomy or its staff.