Sun Was Shining Early On

Artist’s concept of protosun at the center of the solar nebula. Image credit: NASA Click to enlarge
From chemical fingerprints preserved in primitive meteorites, scientists at UCSD have determined that the collapsing gas cloud that eventually became our sun was glowing brightly during the formation of the first material in the solar system more than 4.5 billion years ago.

Their discovery, detailed in a paper that appears in the August 12 issue of Science, provides the first conclusive evidence that this ?protosun? played a major role in chemically shaping the solar system by emitting enough ultraviolet energy to catalyze the formation of organic compounds, water and other compounds necessary for the evolution of life on Earth.

Scientists have long argued whether the chemical compounds created in the early solar system were produced with the help of the energy of the early sun or were formed by other means.

?The basic question was, Was the sun on or was it off?? says Mark H. Thiemens, Dean of UCSD?s Division of Physical Sciences and chemistry professor who headed the research team that conducted the study. ?There is nothing in the geological record before 4.55 billion years ago that could answer this.?

Vinai Rai, a postdoctoral fellow working in Thiemens? lab, came up with a solution, developing an extremely sensitive measurement that could answer the question. He searched for chemical fingerprints of the high-energy wind that emanated from the protosun and became trapped in the isotopes, or forms, of sulfide found in four primitive groups of meteorites, the oldest remnants of the early solar system. Astronomers believe this wind blew matter from the core of the rotating solar nebula into its pancake-like accretion disk, the region in which meteorites, asteroids and planets later formed.

Applying a technique Thiemens developed five years ago to reveal details about the Earth?s early atmosphere from variations in the oxygen and sulfur isotopes embedded in ancient rocks, the UCSD chemists were able to infer from sulfides in the meteorites the intensity of the solar wind and, hence, the intensity of the protosun. They conclude in their paper that the slight excess of one isotope of sulfur, ??S, in the meteorites indicated the presence of ?photochemical reactions in the early solar nebula,? meaning that the protosun was shining strongly enough to drive chemical reactions.

?This measurement tells us for the first time that the sun was on, that there was enough ultraviolet light to do photochemistry,? says Thiemens. ?Knowing that this was the case is a huge help in understanding the processes that formed compounds in the early solar system.?

Astronomers believe the solar nebula began to form about 5 billion years ago when a cloud of interstellar gas and dust was disturbed, possibly by the shock wave of a large exploding star, and collapsed under its own gravity. As the nebula?s spinning pancake-like disk grew thinner and thinner, whirlpools of clumps began to form and grow larger, eventually forming the planets, moons and asteroids. The protosun, meanwhile, continued to contract under its own gravity and grew hotter, developing into a young star. That star, our sun, emanated a hot wind of electrically charged atoms that blew most of the gas and dust that remained from the nebula out of the solar system.

Planets, moons and many asteroids have been heated and had their material reprocessed since the formation of the solar nebula. As a result, they have had little to offer scientists seeking clues about the development of the solar nebula into the solar system. However, some primitive meteorites contain material that has remained unchanged since the protosun spewed this material from the center of the solar nebula more than 4.5 billion years ago.

Thiemens says the technique his team used to determine that the protosun was glowing brightly also can be applied to estimate when and where various compounds originated in the hot wind spewed out by the protosun.

?That will be the next goal,? he says. ?We can look mineral by mineral and perhaps say here?s what happened step by step.?

The UCSD team?s study was financed by a grant from the National Aeronautics and Space Administration.

Original Source: UCSD News Release

Mars Reconnaissance Orbiter Launched

NASA’s Mars Reconnaissance Orbiter (MRO) launch. Image credit: NASA/KSC Click to enlarge
A seven-month flight to Mars began this morning for NASA’s Mars Reconnaissance Orbiter (MRO). It will inspect the red planet in fine detail and assist future landers.

An Atlas V launch vehicle, 19 stories tall with the two-ton spacecraft on top, roared away from Launch Complex 41 at Cape Canaveral Air Force Station at 7:43 a.m. EDT. Its powerful first stage consumed about 200 tons of fuel and oxygen in just over four minutes, then dropped away to let the upper stage finish the job of putting the spacecraft on a path toward Mars. This was the first launch of an interplanetary mission on an Atlas V.

“We have a healthy spacecraft on its way to Mars and a lot of happy people who made this possible,” said James Graf, project manager for MRO at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif.

MRO established radio contact with controllers 61 minutes after launch and within four minutes of separation from the upper stage. Initial contact came through an antenna at the Japan Aerospace Exploration Agency’s Uchinoura Space Center in southern Japan.

Health and status information about the orbiter’s subsystems were received through Uchinoura and the Goldstone, Calif., antenna station of NASA’s Deep Space Network. By 14 minutes after separation, the craft’s solar panels finished unfolding, enabling the MRO to start recharging batteries and operate as a fully functional spacecraft.

The orbiter carries six scientific instruments for examining the surface, atmosphere and subsurface of Mars in unprecedented detail from low orbit. For example, its high-resolution camera will reveal features as small as a dishwasher. NASA expects to get several times more data about Mars from MRO than from all previous Martian missions combined.

Researchers will use the instruments to learn more about the history and distribution of Mars’ water. That information will improve understanding of planetary climate change and will help guide the quest to answer whether Mars ever supported life. The orbiter will also evaluate potential landing sites for future missions. MRO will use its high-data-rate communications system to relay information between Mars surface missions and Earth.

Mars is 72 million miles from Earth today, but the spacecraft will travel more than four times that distance on its outbound-arc trajectory to intercept the red planet on March 10, 2006. The cruise period will be busy with checkups, calibrations and trajectory adjustments.

On arrival day, the spacecraft will fire its engines and slow itself enough for Martian gravity to capture it into a very elongated orbit. The spacecraft will spend half a year gradually shrinking and shaping its orbit by “aerobraking,” a technique using the friction of carefully calculated dips into the upper atmosphere to slow the vehicle. The mission’s main science phase is scheduled to begin in November 2006.

The launch was originally scheduled for August 10, but was delayed first due to a gyroscope issue on a different Atlas V, and the next day because of a software glitch.

The mission is managed by JPL, a division of the California Institute of Technology, Pasadena, for the NASA Science Mission Directorate. Lockheed Martin Space Systems, Denver, prime contractor for the project, built both the spacecraft and the launch vehicle.

NASA’s Launch Services Program at the Kennedy Space Center is responsible for government engineering oversight of the Atlas V, spacecraft/launch vehicle integration and launch day countdown management.

For more information about MRO on the Web, visit:
http://www.nasa.gov/mro

Original Source: NASA News Release

Impressions from Cassini

Saturn’s turbulent atmosphere. Image credit: NASA/JPL/SSI Click to enlarge
Saturn’s turbulent atmosphere is reminiscent of a Van Gogh painting in this view from Cassini. However, unlike the famous impressionist painter, Cassini records the world precisely as it appears to the spacecraft’s cameras.
The feathery band that cuts across from the upper left corner to the right side of this scene has a chevron, or arrow, shape near the right. The center of the chevron is located at the latitude (about 28 degrees South) of an eastward-flowing zonal jet in the atmosphere. Counter-flowing eastward and westward jets are the dominant dynamic features seen in the giant planet atmospheres. A chevron-shaped feature with the tip pointed east means that this is a local maximum in the eastward wind and a region of horizontal wind shear, where clouds to the north and south of the jet are being swept back by the slower currents on the sides of the jet.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 6, 2005, at a distance of approximately 2.5 million kilometers (1.5 million miles) from Saturn using a filter sensitive to wavelengths of infrared light centered at 727 nanometers. The image scale is 14 kilometers (9 miles) per pixel.

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, D.C. 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.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Micro Vortices Seen in the Earth’s Magnetosphere

Artist’s impression of micro turbulence seen by Cluster. Image credit: ESA Click to enlarge
Thanks to measurements by ESA?s Cluster mission, a team of European scientists have identified ?micro?-vortices in Earth?s magnetosphere.

Such small-scale vortex turbulence, whose existence was predicted through mathematical models, has not been observed before in space. The results are not only relevant for space physics, but also for other applications like research on nuclear fusion.

On 9 March 2002, the four Cluster satellites, flying in tetrahedral formation at 100 kilometres distance from each other, were crossing the northern ?magnetic cusp? when they made their discovery. Magnetic cusps are the regions over the magnetic poles where the magnetic field lines surrounding Earth form a magnetic funnel.

The magnetic cusps are the two important regions in Earth?s magnetosphere where the ?solar wind? – a constant flow of charged particles generated by the Sun that crosses the whole Solar System – can directly access the upper layer of Earth?s atmosphere (the ionosphere).

Large amounts of plasma (a gas of charged particles) and energy are transported through these and other ?accessible? regions, to penetrate the magnetosphere – Earth?s natural protective shield. Only less than one percent of all the energy carried by the solar wind and hitting the Earth?s magnetosphere actually manages to sneak through, but it still can have a significant impact on earthly systems, like telecommunication networks and power lines.

The solar material sneaking in generates turbulence in the plasma surrounding Earth, similar to that in fluids but with more complex forces involved. Such turbulence is generated for instance in the areas of transition between layers of plasma of different density and temperature, but its formation mechanisms are not completely clear yet.

The turbulence exists at different scales, from few thousand to few kilometres across. With in situ ?multi-point? measurements, the four Cluster satellites reported in the year 2004 the existence of large scale turbulence – vortices up to 40 000 kilometres wide, at the flank of the ?magnetopause? (a boundary layer separating the magnetosphere from free space). The new discovery of ?micro? turbulence, with vortices of only 100 kilometres across, is a first in the study of the plasma surrounding Earth.

Cluster: an unprecedented diagnostic tool

Such a discovery is very relevant. For example, it allows scientists to start linking small and large-scale turbulence, and start questioning how it is actually formed and what are the connections. For instance, what are the basic mechanisms driving and shaping the turbulence? How much do vortices contribute to the transport of mass and energy through boundary layers? Are small vortices needed to generate large ones? Or, on the other hand, do large vortices dissipate their energy and create a cascade of smaller ones?

In trying to answer these questions, Cluster is an unprecedented diagnostic tool for the first three-dimensional map of the near-Earth environment, its exceptionality being given by its multi-spacecraft simultaneous observations. Cluster is revolutionising our understanding of the ways and the mechanisms by which solar activity affects Earth.

Besides, Cluster?s study of the turbulence in Earth?s plasma, with the dynamics and the energies involved, is contributing to the advancement of fundamental theories on plasma. This is not only important in astrophysics, but also as far as the understanding and the handling of plasma in laboratories is concerned, given the high energies involved. This is particularly relevant for research on nuclear fusion.

For example, Cluster?s data are complementing research on plasma physics in the international ITER project, an experimental step involving several research institutes around the world for tomorrow?s electricity-producing power plants. In this respect, by probing into the magnetosphere, Cluster has free access to the only open ?natural laboratory? for the study of plasma physics.

Original Source: ESA Portal

Anti-Hurricanes on Saturn

Saturn’s anti-hurricanes. Image credit: NASA/JPL/SSI Click to enlarge
Vortices mingle amidst other turbulent motions in Saturn’s atmosphere in these two comparison images. The image on the right was taken about two Saturn rotations after the image on the left.

Both views show latitudes from minus 23 degrees to minus 42 degrees. The region below center in these images (at minus 35 degrees) has seen regular storm activity since Cassini first approached Saturn in early 2004. Cassini investigations of the atmosphere from February to October 2004 showed that most of the oval-shaped storms in the latitude region near minus 35 degrees rotate in a counter-clockwise direction, with smaller storms occasionally merging into larger ones (see Saturn Movie and Saturn Movie Closeup for a movie of storm activity in this region).

On Earth, hurricanes in the Southern Hemisphere rotate clockwise. Thus, the storms in these images of Saturn’s southern latitudes could be called “anti-hurricanes.” This backwards spiraling (compared to Earth) is common on the giant planets.

The images were taken with the Cassini spacecraft narrow-angle camera on July 4 and 5, 2005, using a filter sensitive to wavelengths of infrared light centered at 750 nanometers. During this time, Cassini’s distance from Saturn was approximately 2.4 million kilometers (1.5 million miles). The image scale is about 14 kilometers (9 miles) per pixel.

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, D.C. 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.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Largest Communications Satellite Launched

Ariane 5G launcher lifting off. Image credit: ESA/CNES/Arianespace Click to enlarge
This morning an Ariane 5G launcher lifted off from Europe?s Spaceport in French Guiana. On board was the largest telecommunications satellite ever to be placed into geostationary transfer orbit.

The mission was initially delayed during the two-hour-long launch window to verify telemetry readings from Ariane 5’s mobile launch table, and the countdown subsequently resumed for an early morning takeoff from the ELA-3 launch zone.
The heavyweight THAICOM 4 (IPSTAR) satellite had a lift-off mass of almost 6500 kg. Before this morning?s launch, the record for the heaviest telecommunications satellite to be placed into orbit belonged to the Anik F2 satellite, launched by an Ariane 5 launcher in July 2004.

THAICOM 4, built for Shin Satellite Plc of Thailand, will provide businesses and consumers throughout Asia, Australia and New Zealand with various levels of Internet access services. The satellite has a total data throughput capacity of over 45 Gbps. This is the fourth Shin Satellite to be launched by an Ariane vehicle. An Ariane 4 vehicle launched the first satellite in 1993.

The next launch to take place from Europe?s Spaceport will be Flight 168, an Ariane 5G dual launch mission scheduled for 29 September

Original Source: ESA Portal

Static Electricity… in Space

Artist’s concept of possible exploration programs. Image credit: NASA Click to enlarge
Have you ever walked across a wool carpet in leather-soled shoes on a dry winter day, and then reached out toward a doorknob? ZAP! A stinging spark leaps between your fingers and the metal knob.

That’s static discharge–lightning writ small.

Static discharge is merely annoying to anyone on Earth living where winters have exceptionally low humidity. But to astronauts on the Moon or on Mars, static discharge could be real trouble.

“On Mars, we think the soil is so dry and insulating that if an astronaut were out walking, once he or she returned to the habitat and reached out to open the airlock, a little lightning bolt might zap critical electronics,” explains Geoffrey A. Landis, a physicist with the Photovoltaics and Space Environmental Effects Branch at NASA Glenn Research Center in Cleveland, Ohio.

This phenomenon is called triboelectric charging.

The prefix “tribo” (pronounced TRY-bo) means “rubbing.” When certain pairs of unlike materials, such as wool and hard shoe-sole leather, rub together, one material gives up some of its electrons to the other material. The separation of charge can create a strong electric field.

Here on Earth, the air around us and the clothes we wear usually have enough humidity to be decent electrical conductors, so any charges separated by walking or rubbing have a ready path to ground. Electrons bleed off into the ground instead of accumulating on your body.

But when air and materials are extraordinarily dry, such as on a dry winter’s day, they are excellent insulators, so there is no ready pathway to ground. Your body can accumulate negative charges, possibly up to an amazing 20 thousand volts. If you touch a conductor, such as a metal doorknob, then–ZAP!–all the accumulated electrons discharge at once.

On the Moon and on Mars, conditions are ideal for triboelectric charging. The soil is drier than desert sand on Earth. That makes it an excellent electrical insulator. Moreover, the soil and most materials used in spacesuits and spacecraft (e.g., aluminized mylar, neoprene-coated nylon, Dacron, urethane-coated nylon, tricot, and stainless steel) are completely unlike each other. When astronauts walk or rovers roll across the ground, their boots or wheels gather electrons as they rub through the gravel and dust. Because the soil is insulating, providing no path to ground, a space suit or rover can build up tremendous triboelectric charge, whose magnitude is yet unknown. And when the astronaut or vehicle gets back to base and touches metal–ZAP! The lights in the base may go out, or worse.

Landis and colleagues at NASA Glenn first noticed this problem in the late 1990s before Mars Pathfinder was launched. “When we ran a prototype wheel of the Sojourner rover over simulated Martian dust in a simulated Martian atmosphere, we found it charged up to hundreds of volts,” he recalls.

That discovery so concerned the scientists that they modified Pathfinder’s rover design, adding needles half an inch long, made of ultrathin (0.0001-inch diameter) tungsten wire sharpened to a point, at the base of antennas. The needles would allow any electric charge that built up on the rover to bleed off into the thin Martian atmosphere, “like a miniature lightning rod operating in reverse,” explains Carlos Calle, lead scientist at NASA’s Electrostatics and Surface Physics Laboratory at Kennedy Space Center, Florida. Similar protective needles were also installed on the Spirit and Opportunity rovers.

On the Moon, “Apollo astronauts never reported being zapped by electrostatic discharges,” notes Calle. “However, future lunar missions using large excavation equipment to move lots of dry dirt and dust could produce electrostatic fields. Because there’s no atmosphere on the Moon, the fields could grow quite strong. Eventually, discharges could occur in vacuum.”

“On Mars,” he continues, “discharges can happen at no more than a few hundred volts. It’s likely that these will take the form of coronal glows rather than lightning bolts. As such, they may not be life threatening for the astronauts, but they could be harmful to electronic equipment.”

So what’s the solution to this problem?

Here on Earth, it’s simple: we minimize static discharge by grounding electrical systems. Grounding them means literally connecting them to Earth–pounding copper rods deep into the ground. Ground rods work well in most places on Earth because several feet deep the soil is damp, and is thus a good conductor. The Earth itself provides a “sea of electrons,” which neutralizes everything connected to it, explains Calle.

There’s no moisture, though, in the soil of the Moon or Mars. Even the ice believed to permeate Martian soil wouldn’t help, as “frozen water is not a terribly good conductor,” says Landis. So ground rods would be ineffective in establishing a neutral “common ground” for a lunar or Martian colony.

On Mars, the best ground might be, ironically, the air. A tiny radioactive source “such as that used in smoke detectors,” could be attached to each spacesuit and to the habitat, suggests Landis. Low-energy alpha particles would fly off into the rarefied atmosphere, hitting molecules and ionizing them (removing electrons). Thus, the atmosphere right around the habitat or astronaut would become conductive, neutralizing any excess charge.

Achieving a common ground on the Moon would be trickier, where there’s not even a rarefied atmosphere to help bleed off the charge. Instead, a common ground might be provided by burying a huge sheet of foil or mesh of fine wires, possibly made of aluminum (which is highly conductive and could be extracted from lunar soil), underneath the entire work area. Then all the habitat’s walls and apparatus would be electrically connected to the aluminum.

Research is still preliminary. So ideas differ amongst the physicists who are seeking, well, some common ground.

Original Source: NASA News Release

Galaxies Could Be Twice as Large as Previously Estimated

A wide-field view of NGC 300. Image credit: AAO-David Malin/Gemini Observatory. Click to enlarge
Like archaeologists unearthing a ‘lost city,’ astronomers using the 8-meter Gemini South telescope have revealed that the galaxy NGC 300 has a large, faint extended disk made of ancient stars, enlarging the known diameter of the galaxy by a factor of two or more.

The finding also implies that our own Milky Way Galaxy could be much larger than current textbooks say. Scientists will also need to explain the mystery of how galaxies like NGC 300 can form with stars so far from their centers.

The research, by an Australian and American team of scientists was just published in the August 10, 2005 issue of the Astrophysical Journal.

The team used the Gemini Multi-Object Spectrograph on the Gemini South telescope in Chile, and were able to clearly resolve extremely faint stars in the disk up to 47,000 light-years from the galaxy?s center?double the previously known radius of the disk. To detect these stars, images were obtained that went more than ten times ?deeper? than any previous images of this galaxy (Figure 1).

?A few billion years ago the outskirts of NGC 300 were brightly lit suburbs that would have shown up as clearly as its inner metropolis,? said the paper?s lead author, Professor Joss Bland-Hawthorn of the Anglo-Australian Observatory in Sydney, Australia. ?But the suburbs have dimmed with time, and are now inhabited only by faint, old stars?stars that need large telescopes such as Gemini South to detect them.?

The finding has profound implications for our own galaxy since most current estimates put the size of our Milky Way at about 100,000 light-years or about the size now estimated for NGC 300. ?However, the galaxy is much more massive and brighter than NGC 300 so on this basis, our galaxy is also probably much larger than we previously thought?perhaps as much as 200,000 light-years across,? said Bland-Hawthorn.

The Galaxy That Keeps On Keeping On!

Adding to these compelling findings is the fact that the team found no evidence for truncating, or an abrupt ?cutting-off’ of the star population as seen in many galaxies further from the central regions.

Team member Professor Bruce Draine of Princeton University explains: “It’s hard to understand how such an extensive stellar disk that falls off so smoothly in density could have formed ? this is really a huge surprise to us. Because it takes an incredibly long time to evenly disperse stars from a galaxy’s central disk to these extreme distances, it seems more likely that we are seeing the results of star formation that took place long ago, perhaps as much as ten billion years ago.”

?We now realize that there are distinctly different types of galaxy disks,? said team member Professor Ken Freeman of the Research School of Astronomy and Astrophysics at the Australian National University. ?Probably most galaxies are truncated?the density of stars in the disk drops off sharply. But NGC 300 just seems to go on forever. The density of stars in the disk falls off very smoothly and gradually.?

The observers traced NGC 300?s disk out to the point where the surface density of stars was equivalent to a one-thousandth of a sun per square light-year. ?This is the most extended and diffuse population of stars ever seen,? said Bland-Hawthorn.

NGC 300 is a spiral member of the Sculptor group of galaxies, the closest extragalactic cluster to us, and is about 6.1 million light-years away. Most of its stars lie in a fairly flat disk making it appear to be a very normal spiral galaxy like our Milky Way. NGC 300 is the first galaxy outside of our Local Group to be studied to this depth. There have only been two others studied to such faint levels, the Andromeda galaxy and its neighbor M33, both in our Local Group (see adjacent background information box).

The researchers have been granted more time on Gemini South to determine exactly what kind of stars they are seeing in the outskirts of NGC 300, and to make similar studies of other galaxies.

?We still have a lot to learn about how galaxies like ours formed,? said Bland-Hawthorn. ?Our next Gemini observations, that we have planned for later this year, should provide even more important clues and hopefully even more surprises!?

Original Source: Gemini Observatory

Zo? Heads Back to the Desert to Search for Life

Zo?, an autonomous solar-powered rover. Image credit: NASA Click to enlarge
Carnegie Mellon University researchers and their colleagues from NASA’s Ames Research Center, the universities of Tennessee, Arizona and Iowa, as well as Chilean researchers at Universidad Catolica del Norte (Antofagasta) are preparing for the final stage of a three-year project to develop a prototype robotic astrobiologist, a robot that can explore and study life in the driest desert on Earth.

The team will direct and monitor Zo?, an autonomous solar-powered rover developed at Carnegie Mellon, as it travels 180 kilometers in Chile’s Atacama Desert. Zo? is equipped with scientific instruments to seek and identify micro-organisms and to characterize their habitats. It will use them as it explores three diverse regions of the desert during its two-month stay, which runs from August 22 to October 22.

The results of this expedition ultimately may enable future robots to seek life on Mars, as well as enabling the discovery of new information about the distribution of life on Earth.

The search-for-life project was begun in 2003 under NASA’s Astrobiology Science and Technology Program for Exploring Planets, or ASTEP, which concentrates on pushing the limits of technology to study life in harsh environments.

Zo?’s abilities represent the culmination of three years of work to determine the optimum design, software and instrumentation for a robot that can autonomously investigate different habitats. During the 2004 field season, Zo? exceeded scientists’ expectations when it traveled 55 kilometers autonomously and detected living organisms using its onboard Fluorescence Imager (FI) to locate chlorophyll and other organic molecules.

“Our goal with this final investigation is to develop a method to create a real-time, 3D topographic ‘map’ of life at the microscopic level,” said Nathalie Cabrol, a planetary scientist at NASA Ames and the SETI Institute who heads the science investigation aspects of the project. “This map eventually could be integrated with satellite data to create an unprecedented tool for studies of large-scale environmental activities on life in specific areas. This concept can be applied to planetary research and also on Earth to explore other extreme environments.”

“This is the first time a robot is looking for life,” said Carnegie Mellon associate research professor David Wettergreen, who leads the project. “We have worked with rovers and individual instruments before, but Zo? is a complete system for life seeking. We are working toward full autonomy of each day’s activities, including scheduling time and resource use, control of instrument deployment and navigation between study areas.

“Last year we learned that the Fluorescence Imager can detect organisms in this environment. This year we’ll be able to see how densely an area is populated with organisms and map their distribution. We intend to have the robot make as many as 100 observations and make advances in procedural developments like how to decide where to explore.”

Zo? will visit a foggy coastal region, the dry Andean altiplano, and an area in the desert’s arid interior that receives no precipitation for decades at a time. At these sites, the rover’s activities will be guided remotely from an operations center in Pittsburgh where the researchers will characterize the environment, seek clear proof of life and map the distribution of various habitats. During last year’s mission, the team carried out experiments using an imager able to detect fluorescence in an area underneath the rover. The FI detects signals from two fluorescent dyes that mark carbohydrates and proteins ? as well as the natural fluorescence of chlorophyll. The FI, developed by Alan Waggoner, director of the university’s Molecular Biosensor and Imaging Center (MBIC), was not fully automated last year. Scientists had to follow the rover and spray dyes onto the sample area. This year, Zo? can spray a mixture of dyes for DNA, protein, lipid and carbohydrates without human intervention.

The Life in the Atacama project is funded with a $3 million, three-year grant from NASA to Carnegie Mellon’s Robotics Institute in the School of Computer Science. They collaborate with MBIC scientists, who received a separate $900,000 NASA grant to develop fluorescent dyes and automated microscopes to locate various forms of life.

The science team uses EventScope, a remote experience browser developed by researchers at the STUDIO for Creative Inquiry in Carnegie Mellon’s College of Fine Arts, to guide Zo?. It enables scientists and the public to experience the Atacama environment through the rover’s “eyes” and various sensors. During the field investigation, scientists will interact with Zo? in a science operations control room at the Remote Experience and Learning Lab in Pittsburgh. Scientists from NASA, the Jet Propulsion Laboratory, the University of Tennessee, University of Arizona, the British Antarctic Survey and the European Space Agency will participate.

For more information, images and field reports from the Atacama, visit: www.frc.ri.cmu.edu/atacama.

Original Source: Carnegie Mellon News Release

Triple Asteroid System Discovered

Orbits of twin moonlets around 87 Sylvia. Image credit: ESO Click to enlarge
One of the thousands of minor planets orbiting the Sun has been found to have its own mini planetary system. Astronomer Franck Marchis (University of California, Berkeley, USA) and his colleagues at the Observatoire de Paris (France) have discovered the first triple asteroid system – two small asteroids orbiting a larger one known since 1866 as 87 Sylvia.

“Since double asteroids seem to be common, people have been looking for multiple asteroid systems for a long time,” said Marchis. “I couldn’t believe we found one.”

The discovery was made with Yepun, one of ESO’s 8.2-m telescopes of the Very Large Telescope Array at Cerro Paranal (Chile), using the outstanding image’ sharpness provided by the adaptive optics NACO instrument. Via the observatory’s proven “Service Observing Mode”, Marchis and his colleagues were able to obtain sky images of many asteroids over a six-month period without actually having to travel to Chile.

One of these asteroids was 87 Sylvia, which was known to be double since 2001, from observations made by Mike Brown and Jean-Luc Margot with the Keck telescope. The astronomers used NACO to observe Sylvia on 27 occasions, over a two-month period. On each of the images, the known small companion was seen, allowing Marchis and his colleagues to precisely compute its orbit. But on 12 of the images, the astronomers also found a closer and smaller companion. 87 Sylvia is thus not double but triple!

Because 87 Sylvia was named after Rhea Sylvia, the mythical mother of the founders of Rome, Marchis proposed naming the twin moons after those founders: Romulus and Remus. The International Astronomical Union approved the names.

Sylvia’s moons are considerably smaller, orbiting in nearly circular orbits and in the same plane and direction. The closest and newly discovered moonlet, orbiting about 710 km from Sylvia, is Remus, a body only 7 km across and circling Sylvia every 33 hours. The second, Romulus, orbits at about 1360 km in 87.6 hours and measures about 18 km across.

The asteroid 87 Sylvia is one of the largest known from the asteroid main belt, and is located about 3.5 times further away from the Sun than the Earth, between the orbits of Mars and Jupiter. The wealth of details provided by the NACO images show that 87 Sylvia is shaped like a lumpy potato, measuring 380 x 260 x 230 km. It is spinning at a rapid rate, once every 5 hours and 11 minutes.

The observations of the moonlets’ orbits allow the astronomers to precisely calculate the mass and density of Sylvia. With a density only 20% higher than the density of water, it is likely composed of water ice and rubble from a primordial asteroid. “It could be up to 60 percent empty space,” said co-discoverer Daniel Hestroffer (Observatoire de Paris, France).

“It is most probably a “rubble-pile” asteroid”, Marchis added. These asteroids are loose aggregations of rock, presumably the result of a collision. Two asteroids smacked into each other and got disrupted. The new rubble-pile asteroid formed later by accumulation of large fragments while the moonlets are probably debris left over from the collision that were captured by the newly formed asteroid and eventually settled into orbits around it. “Because of the way they form, we expect to see more multiple asteroid systems like this.”

Marchis and his colleagues will report their discovery in the August 11 issue of the journal Nature, simultaneously with an announcement that day at the Asteroid Comet Meteor conference in Arma??o dos B?zios, Rio de Janeiro state, Brazil.

Original Source: ESO News Release