MARS METHANE BOOSTS CHANCES FOR LIFE Last week the European Space Agency reported new results from Mars Express that bolster the hope that small colonies of microbes may be eking out an existence under the Martian surface today. Atmospheric data from the orbiter's Planetary Fourier Spectrometer show that water vapor and methane show up together above three equatorial regions that overlie subsurface ice -- suggesting a common underground origin. Methane is considered a possible biomarker. It breaks down rapidly in Mars's atmosphere, so it's presence is intriguing. Some source -- biological or geological -- must constantly replenish the gas.... > http://SkyandTelescope.com/news/article_1358_1.asp

Jueves, 14 de Octubre de 2004 Actualizado a las 00:03 (CET) - Internet time @960 by CONTARÁ CON LOS EQUIPOS MÁS MODERNOS La NASA enviará una nave que orbitará sobre Marte para futuras misiones en ese planeta EFE NOTICIAS RELACIONADAS WASHINGTON.- La NASA enviará en agosto del próximo año una nave que orbitará a Marte con el objetivo de determinar posibles puntos de descenso para futuras misiones en ese planeta, según ha anunciado oficialmente este miércoles el organismo. 'Mars Reconnaissance Orbiter' partirá desde el Centro Espacial Kennedy, en Cabo Cañaveral (Florida), y contará con los equipos más modernos disponibles, informó en un comunicado la Administración Nacional de Aeronáutica y del Espacio (NASA). Señaló que cámaras telescópicas revelarán los más mínimos detalles de la superficie marciana y que otros equipos científicos transmitirán información sobre el planeta diez veces más rápido que las misiones anteriores. En estos momentos, dos exploradores robóticos recorren la superficie del planeta, mientras una sonda gira en órbita fija en torno a él. "'El Mars Reconnaissance Orbiter' será una de las misiones más importantes enviadas a Marte", dijo Jim Graf, director del proyecto. "Se trata de una próxima generación de orbitadores que trabajará de manera coordinada con las misiones de superficie para darnos nueva información sobre los procesos que dan forma al planeta", añadió. Graf dará a conocer más detalles sobre el proyecto en una conferencia de prensa que ofrecerá este juves en el Laboratorio de Propulsión a Chorro (JPL) de la NASA, en Pasadena (California). http://www.elmundo.es/elmundo/2004/10/13/ciencia/1097704733.html

Field of Fault Lines on Mars Oct 5, 2004 - This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, shows the Claritas Fossae tectonic grabens and part of the Solis Planum plains. The image was taken during orbit 508 in June 2004 with a ground resolution of approximately 40 metres per pixel. The displayed region is the eastern part of Claritas Fossae and the western part of Solis Planum at longitude 260° East and latitude of about 28° South. The diffuse blue-white streaks in the northern parts of the scene are clouds or aerosols. The Claritas Fossae (‘fossa’ is Latin for trough) region is characterised by systems of ‘grabens’ running mainly north-west to south-east. These can be traced several hundred kilometres up to the northern Tharsis shield volcanoes. A graben forms when a block of the planet’s crust drops down between two faults, due to extension, or pulling, of the crust. Grabens are often seen together with features called ‘horsts’, which are upthrown blocks lying between two steep-angled fault blocks. A ‘horst and graben’ system can occur where there are several parallel faults. Geographically, the grabens separate the eastern volcanic plains of the Solis Planum region from the western Daedalia Planum lava plains. The lava blankets of the Solis Planum area cover the eastern parts of the older Claritas Fossae ridge and surround some of the higher ground. The geological history of this region can be reconstructed by analysing the layers of tectonic grabens, impact craters, volcanic features and even small valley networks. The complexity of this superposition record suggests that some of the events took place at the same time. The detailed view of the large southern impact crater shows patches of dark material which are located near the central and marginal parts of the impact crater floor. This material may be of volcanic origin. The HRSC experiment on ESA’s Mars Express mission is led by the Principal Investigator Prof. Gerhard Neukum of the Freie Universität Berlin, who also designed the camera. The experiment’s science team consists of 45 Co-Investigators from 10 nations. The camera was developed at the German Aerospace Centre (DLR) and built in co-operation with industrial partners EADS Astrium, Lewicke Microelectronic GmbH and Jena-Optronic GmbH). The HRSC is operated by DLR Institute of Planetary Research through ESA’s European Space Operations Centre, Darmstadt. The systematic processing of image data is carried out at DLR. The images shown here were processed by the FU Berlin group in co-operation with DLR, Berlin. Original Source: ESA News Release -------------------------------------------------------------------------------- Copyright © 1999-2004 Universe Today, All rights reserved. http://www.universetoday.com http://www.universetoday.com/am/publish/printer_field_fault_lines_mars.html

Epsom Salts Could Be a Source of Martian Water Summary - (Oct 7, 2004) Researchers from Indiana University have found that under Mars-like conditions, Epsom-like salts can contain a significant amount of water. This could help explain why NASA's Mars Odyssey spacecraft discovered a large amount of water near the surface of Mars, but it's not visible. To get to the bottom of this possibility, the researchers have been funded by NASA to help build an X-ray diffractometer, which a future rover would use to analyze crystals on Mars to see if they're the right kind of salt that could contain water. Full Story - Epsom-like salts believed to be common on Mars may be a major source of water there, say geologists at Indiana University Bloomington and Los Alamos National Laboratory. In their report in this week's Nature, the scientists also speculate that the salts will provide a chemical record of water on the Red Planet. "The Mars Odyssey orbiter recently showed that there may be as much as 10 percent water hidden in the Martian near-surface," said David Bish, Haydn Murray Chair of Applied Clay Mineralogy at IU and a co-author of the report. "We were able to show that under Mars-like conditions, magnesium sulfate salts can contain a great deal of water. Our findings also suggest that the kinds of sulfates we find on Mars could give us a lot of insight into the history of water and mineral formation there." The scientists learned that magnesium sulfate salts are extremely sensitive to changes in temperature, pressure and humidity. For that reason, the scientists argue that information contained in the salts could be easily lost if samples were brought back to Earth for study. Instead, they say, future missions to Mars should measure the properties of the salts on site. The existence of magnesium sulfate salts on Mars was first suggested by the 1976 Viking missions and has since been confirmed by the Mars Exploration Rover as well as the Odyssey and Pathfinder missions. One way to quash remaining doubts that the salts are really there, however, would be to equip a Martian rover with an X-ray diffractometer -- an instrument that analyzes the properties of crystals. Coincidentally, such a device could also be used to examine magnesium sulfate salts on Mars. Bish and collaborators from NASA Ames and Los Alamos are currently developing a miniaturized X-ray diffractometer with NASA funding. Some magnesium sulfate salts trap more water than others. Epsomite, for example, has the most water in it -- 51 percent by weight -- while hexahydrite and kieserite have less (47 percent and 13 percent by weight, respectively). The proportion of water to magnesium sulfate affects the chemical properties of the different salts. While varying temperature, pressure and humidity inside an experimental chamber, the scientists studied how the different magnesium salts transform over time. When temperature and pressure inside an experimental chamber were lowered to Mars-like conditions (minus 64 degrees Fahrenheit, and less than 1 percent of Earth's normal surface pressure), crystals of epsomite initially transformed into slightly less watery hexahydrite crystals and then became disorganized, but they still contained water. In contrast, "kieserite doesn't let go of its water very easily, even at very low pressure and humidity or at elevated temperatures," Bish said. But when the scientists increased humidity inside the experimental chamber, they found that kieserite transformed into hexahydrite and then epsomite, which have more water. Bish and his Los Alamos colleagues believe that the proportion and distribution of hexahydrite, kieserite and other magnesium sulfate salts on Mars may hold a record of past changes in climate and whether or not water once flowed there. However, kieserite might not be preserved through cycles of wetting and drying because of its ability to rehydrate to hexahydrite and epsomite, which can then become amorphous through drying. Los Alamos National Laboratory geologists David Vaniman, Steve Chipera, Claire Fialips, William Carey and William Feldman also contributed to the study. It was funded by LANL Directed Research and Development Funding and NASA Mars Fundamental Research Program grants. http://www.universetoday.com/am/publish/epsom_salts_source_mars_water.html?7102004 http://newsinfo.iu.edu/news/page/normal/1673.html

Rovers Still Turning Up Water Evidence Summary - (Oct 8, 2004) Now operating three times longer than originally expected, NASA's Mars Exploration Rovers are still turning up fresh evidence that liquid water once flowed on Mars. Opportunity has found a rock, dubbed "Escher", which has a network of cracks similar to cracked mud when the water has dried up. On the other side of Mars, Spirit is still climbing up the "Columbia Hills", and it seems that every rock it looks at shows evidence that it was altered by water. "We haven't seen a single unaltered volcanic rock, since we crossed the boundary from the plains into the hills, and I'm beginning to suspect we never will," said principal investigator Dr. Steve Squyres. Full Story - NASA's Spirit and Opportunity have been exploring Mars about three times as long as originally scheduled. The more they look, the more evidence of past liquid water on Mars these robots discover. Team members reported the new findings at a news briefing today. About six months ago, Opportunity established that its exploration area was wet a long time ago. The area was wet before it dried and eroded into a wide plain. The team's new findings suggest some rocks there may have gotten wet a second time, after an impact excavated a stadium sized crater. Evidence of this exciting possibility has been identified in a flat rock dubbed "Escher" and in some neighboring rocks near the bottom of the crater. These plate-like rocks bear networks of cracks dividing the surface into patterns of polygons, somewhat similar in appearance to cracked mud after the water has dried up here on Earth. Alternative histories, such as fracturing by the force of the crater-causing impact, or the final desiccation of the original wet environment that formed the rocks, might also explain the polygonal cracks. Rover scientists hope a lumpy boulder nicknamed "Wopmay," Opportunity's next target for inspection, may help narrow the list of possible explanations. "When we saw these polygonal crack patterns, right away we thought of a secondary water event significantly later than the episode that created the rocks," said Dr. John Grotzinger. He is a rover-team geologist from the Massachusetts Institute of Technology, Cambridge, Mass. Finding geological evidence about watery periods in Mars' past is the rover project's main goal, because such persistently wet environments may have been hospitable to life. "Did these cracks form after the crater was created? We don't really know yet," Grotzinger said. If they did, one possible source of moisture could be accumulations of frost partially melting during climate changes, as Mars wobbled on its axis of rotation, in cycles of tens of thousands of years. According to Grotzinger, another possibility could be the melting of underground ice or release of underground water in large enough quantity to pool a little lake within the crater. One type of evidence Wopmay could add to the case for wet conditions after the crater formed would be a crust of water-soluble minerals. After examining that rock, the rover team's plans for Opportunity are to get a close look at a tall stack of layers nicknamed "Burns Cliff" from the base of the cliff. The rover will then climb out of the crater and head south to the spacecraft's original heat shield and nearby rugged terrain, where deeper rock layers may be exposed. Halfway around Mars, Spirit is climbing higher into the "Columbia Hills." Spirit drove more than three kilometers (approximately two miles) across a plain to reach them. After finding bedrock that had been extensively altered by water, scientists used the rover to look for relatively unchanged rock as a comparison for understanding the area's full range of environmental changes. Instead, even the freshest-looking rocks examined by Spirit in the Columbia Hills have shown signs of pervasive water alteration. "We haven't seen a single unaltered volcanic rock, since we crossed the boundary from the plains into the hills, and I'm beginning to suspect we never will," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science payload on both rovers. "All the rocks in the hills have been altered significantly by water. We're having a wonderful time trying to work out exactly what happened here." More clues to deciphering the environmental history of the hills could lie in layered rock outcrops farther upslope, Spirit's next targets. "Just as we worked our way deeper into the Endurance crater with Opportunity, we'll work our way higher and higher into the hills with Spirit, looking at layered rocks and constructing a plausible geologic history," Squyres said. Jim Erickson, rover project manager at JPL, said, "Both Spirit and Opportunity have only minor problems, and there is really no way of knowing how much longer they will keep operating. However we are optimistic about their conditions, and we have just been given a new lease on life for them, a six-month extended mission that began Oct. 1. The solar power situation is better than expected, but these machines are already well past their design life. While they're healthy, we'll keep them working as hard as possible." JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Science Mission Directorate, Washington. Images and additional information about the project are available from JPL and Cornell at http://marsrovers.jpl.nasa.gov and http://athena.cornell.edu. http://www.universetoday.com/am/publish/rovers_still_turning_up_water.html?8102004

El polvo desdibuja el paisaje marciano Imagen: ESA Esta imagen de un paisaje marciano fue tomada por la nave espacial Mars Express de la Agencia Espacial Europea ESA, en Mayo de 2004. Muestra un área en la región Promethei Terra, la cual está relativamente alisada, pero cubierta por una capa de polvo o ceniza volcánica de varias decenas de metros de espesor. Esta capa lo ha cubierto todo y tapa los detalles menores; esta es la razón por la cual la imagen aparece levemente difusa. Extender en El Mensajero de los Astros... [pasión por la astronomia] Resumen número 438 http://ar.groups.yahoo.com/group/pasionporlaastronomia/

Viernes, 05 de Noviembre de 2004 Actualizado a las 14:30 (CET) - Internet time @604 by POSIBLEMENTE SEAN CENIZAS VOLCÁNICAS La misión 'Spirit' descubre nuevos misterios en la superficie marciana EFE Una simulación del robot Spirit. (Foto: NASA) A D E M Á S ... Todos los gráficos de Marte NOTICIAS RELACIONADAS WASHINGTON.- El vehículo explorador 'Spirit' ha descubierto pruebas de la existencia de cenizas volcánicas cuyos minerales fueron disueltos por la presencia de agua en el planeta Marte, informó la NASA. El hallazgo fue hecho sobre una capa estratificada de rocas diez meses después de que el pequeño vehículo descendiera sobre la superficie del planeta y en las cercanías de un promontorio llamado 'Columbia Hills'. "Nuestra hipótesis principal es que estas rocas fueron ceniza volcánica que cayó desde el aire... y que los minerales contenidos en ella fueron disueltos por el agua", dijo Ray Arvidson, científico principal de la misión. La presencia de agua en el pasado remoto fue confirmada en marzo por el 'Spirit' y el 'Opportunity', su compañero de exploración en el otro extremo del planeta. Ambos vehículos, provistos de instrumentos de estudio geológico y varias cámaras fotográficas, han continuado analizando la superficie marciana superando en más de seis meses, los tres previstos como máximo de vida operativa. Arvidson aclaró que, aunque es una hipótesis, los instrumentos del 'Spirit' parecen confirmar que se trata de cenizas volcánicas. "Es importante señalar que acabamos de comenzar a determinar la textura, mineralogía y química de estas rocas estratificadas", señaló. El científico añadió que otra hipótesis sobre su origen se centra en la posibilidad de que esos materiales hayan sido transportados y depositados por el agua. "En efecto, es posible que la actividad volcánica, el agua y el viento hayan producido las rocas que está examinando el Spirit en estos momentos", dijo. El vehículo está operando regularmente con sus espectrómetros pese a que está sufriendo dos tipos de problemas en sus ruedas, dijo Jim Erickson, director del proyecto en el Laboratorio de Propulsión a Chorro (JPL) de la NASA, en Pasadena (California). "Estamos tratando de resolverlos, pero esto podría ser un anticipo de lo que va a ocurrir debido a que los componentes mecánicos se han desgastado como consecuencia de la prolongada exploración en Marte", agregó. http://www.elmundo.es/elmundo/2004/11/05/ciencia/1099609957.html

Marte podría sufrir actividad volcánica y glaciar en la actualidad EFE/MADRID ImprimirEnviar Los restos de actividad volcánica y glaciar en Marte son «mucho más recientes» de lo que se pensaba e incluso podría estar dándose aún en el presente, según datos revelados ayer por el director científico de la Misión 'Mars Express' de la Agencia Espacial Europea (ESA), Agustín Chicarro. Chicarro, quien participó en una jornada homenaje al astronauta español Pedro Duque organizada por el Centro para el Desarrollo Tecnológico Industrial (CDTI), aseguró que se está comprobando que la actividad sísmica en Marte podría haberse producido tan sólo hace diez millones de años, en lugar de hace 500 millones de años, tal como se pensaba hasta ahora. «Incluso esa actividad podría seguir existiendo, aunque no se tienen pruebas de ello», reveló este científico español afincado en Holanda, después de pronunciar una conferencia y participar en una mesa redonda titulada 'Exploración Espacial y Cooperación Internacional'. Según las investigaciones en Marte, se está viendo que la actividad glaciar es todavía más reciente que la sísmica y que podría datar de hace «un millón de años o incluso menos», y además se trataría de un proceso geológico que sigue existiendo. Chicarro mostró zonas supuestamente erosionadas y con mezclas de distintos tipos de hielo, de épocas más o menos recientes. http://servicios.eldiariomontanes.es/pg041021/prensa/noticias/Sociedad/200410/21/DMO-SOC-133.html

Life in a Lava Tube Presentation by Penny Boston (Part I) Peering Into A Cerberus Fossae Trough MGS MOC Release No. MOC2-576, 16 December 2003 Image Credit: Mars Global Surveyor, Malin Space Systems Penny Boston is one of the leaders of the SLIME team - that's Subsurface Life in Mineral Environments. She studies bizarre microorganisms that live, often under extreme conditions, in subterranean caves. At the recent NASA symposium "Risk and Exploration: Earth, Sea and the Stars," in Monterey, California, Boston talked about the relevance of her work below ground on Earth to the search for life on other worlds. Astrobiology Magazine will present her talk in two parts. In this first part she tells why she focuses her research on cave environments and explains that we have a lot to learn from lava tubes. -------------------------------------------------------------------------------- I've been trying to get to Mars ever since I was a little kid. My solution to this over the last decade or so is to go down instead of go out. That may be as close to going to another planet as I ever get. After my colleagues and I published a paper in 1992 [suggesting that if there were life on Mars it was probably underground], we began looking for ways to study the subsurface. And, of course, the most immediate obvious thing was the new information we were getting from drill holes. People were beginning to drill and to try to look at deep subsurface microbiology. But we discovered that caves were there, and thought that maybe they would be cheaper to get into. So after the early part of my career, working in extreme environments on the surface, I decided to try caving. The first cave I ever caved was Lechuigillia Cave in New Mexico, which is a notoriously difficult cave. All I thought at the time was, "Am I going to live to get out of this? I just have to live to get out of this cave." But after the pain faded, I realized that it was an amazing environment, that I'd never been in any place that was so potentially fascinating for the kinds of exotic microbiology that I was interested in as an astrobiologist. I realized that I could learn how to cave safely, go to these places, and refocus my work to tap into an entire area of biology and mineralogy that had not been studied before. This is a new field, really, in terms of what we've been doing on Earth. It is immediately applicable to consideration of life beyond the planet. So most of my research, now, is focused on one sort of cave or another. If you have only been in caves as an occasional tourist in a show cave, you may think that caves are a rare phenomenon, but really there are a tremendous number of subsurface voids on Earth, of all kinds. They aren't just in calcium carbonate types of environments, which are the ones we often come in contact with, but they really occur in every major rock type. And this is an important lesson for trying to apply our knowledge of Earth caves to other bodies in the solar system. There are many, many ways to make caves. One of the areas of active research that we're engaged in is a set of thought experiments, looking at the basic physics and chemistry of environments and trying to imagine ways that subsurface voids on other planets could be formed. Venus up-close, as photographed by the Soviet Venera 13 lander, which parachuted to the Venusian surface on March 1, 1982. The surface is hot enough to melt lead Credit: Venera The type of caves that we absolutely know exist elsewhere in the solar system are what are known as lava tubes. These are natural outgrowths of flood-basalt type, quiet, flowing lava eruptions. They are essentially rivulets that freeze on the outside. The rock on the outside freezes and forms a very good insulator that then allows the interior to remain molten and to continue to flow through. Eventually, when the eruption stops, they empty out and you have these very beautiful tubes. That's a very different class of cave from the kinds of dissolution-dominated caves that we often think of. It was known and recognized by Ron Greeley and other colleagues, even in the Apollo era, that a lot of structures that they were seeing on the moon were lava tubes, or unroofed sinuous rills (lava tubes without their tops). As we have gotten ever-better imaging of the planet Mars, we have seen that there are lava tubes scattered widely over the planet. They are quite easy to pick out. The gravity on Mars is much lower so lava tubes there scale accordingly. Not only does Mars have enormous examples of volcanism, but it has big whompin' lava tubes. The biggest lava tube on Earth is about 90 kilometers (56 miles) long, in Hawaii. That's the record-holder on Earth, but typically when you look at these features on Mars they're hundreds of kilometers long. And the diameters are equally great. On the average they're 3 to 10 times the size of the average diameter on Earth. They are truly enormous. Jupiter's volcanic moon, Io. Credit: NASA/JPL And when we look at the radar imaging data from Venus missions, we can see that there are tube-like structures associated with even those weird-looking types of volcanic features that we find on Venus. Even Io, which is such a cooking little moon out there, with its tremendous sulfur component, seems to have clear evidence of lava tubes. My dream is that some day we'll get a really good image of one that's made entirely out of molten sulfur. But these are not only fabulous features, they're also places, at least on the moon and Mars - I wouldn't recommend astronauts going to Io or Venus - that can actually be exploited as human habitat. We just finished a study for NIAC (NASA Institute for Advanced Concepts), looking at enabling technologies that we would need to make these usable as structures for astronauts, for future bases on the moon and Mars. -------------------------------------------------------------------------------- Related Web Pages Slime Team Website The Mysterious Lives of Caves Biomes, Inc. Cave Slime Rare Earth Debate Series Interactive Presentation: The Life and Death of Planet Earth http://www.astrobio.net/news/article1260.html

PRESS RELEASE Date Released: Thursday, October 28, 2004 Source: Observatoire de Paris Severe glacial cycles on Mars Since the arrival of Mars Global Surveyor and more recently Mars Odyssey spacecrafts, a range of facts has revealed the existence of frozen water ice in the top meters of high latitudes near-surface (~60 deg - 90 deg) of both martian hemispheres. However, its origin was still unexplained. Climatic simulations directed by astronomers from Paris Observatory and researchers from IPSL Planetology Departement (Paris VI) and published in the journal "Nature", show that this ice may come from an ancient reservoir of equatorial ice created during high obliquity episodes on Mars but which became unstable during the more recent episodes of low obliquity. This study has permitted to illustrate the existence of glacial cycles on Mars even more severe than on Earth. Even if the presence of ice caps has been observed on the Mars poles for more than three centuries, the arrival of Mars Global Surveyor and Mars Odyssey spacecrafts in 1996 and 2001 has permitted to show that important quantities of ice (more than 70% of volume) had undoubtedly also been present in the top two meters of martian high latitudes (Figure 1). It seemed difficult to explain the existence of such a quantity of ice so nearby the surface: more than half a milimeter of water frost is currently laying down during autumn and winter at high latitudes. Nevertheless, this ice cap sublimates completely at the end of spring. This ice was proposed to be resulted from a slow diffusion of water between the Martian regolith and the atmosphere but the in situ measurements of porosity from Viking spacecrafts have shown that the regolith can not contain any ice with such a concentration. The study directed by the researchers from Paris Observatory and IPSL suggests that the solution may come from astronomical forcing of Martian climates. For almost thirty years, sedimentary and ice cores have confirmed that the variations of the insolation received on the Earth's surface resulting from slow changes of the orbit and the Earth's obliquity had given rise to glacial/interglacial periods. However, the martian obliquity variations are chaotic and much more significant than on Earth. The Martian obliquity has indeed varied between 25 deg and 45 deg during the 5-10 Ma time intervall and between ~15 deg and 35 deg during the last 5 Ma, with a "periodicity" close to 120 000 years. A climatic 3-dimensional model of General Martian Circulation developed by the team of François Forget (IPSL, Paris VI) and simulating faithfully the current seasonal cycle of water has been used to determine the path of Martian ice through these large variations. These simulations have brought the intense latitudinal redistribution of Martian ice to light. When the obliquity overpasses 35 deg (compared to the current average value which is of ~25.19 deg), the summer insolation becomes too strong to maintain the stability of the current Northern cap which provokes a quick atmospheric transfer of ice towards the equatorial high topography region of Tharsis (Arsia, Pavonis, Ascraeus et Olympus Montes). Remarkably, these summits sides present morphological traces which may be the result of the recent presence of glaciers. When the obliquity is below the current value, the equatorial ice becomes unstable and is carried not only to the polar zones but also to the high latitudes of the both hemispheres. The latitudinal distribution of stable ice obtained is then very close to the Mars Odyssey observations, illustrating a severe martian ice age. How this ice can be preserved? As it is currently observed on Mars, ice is expected to be co-deposited with dust. When ice begins to sublimates, a dust lag is forming and prevents some ice from complete sublimation at every cycle so as to permit a "regular" forming of sedimentary meters-thick and ice-rich layers. These deposits are visible at high latitudes and more spectacularly in the polar caps. The ice observed by Mars Odyssey would also be the mark of an ancient Martian glacial age (probably inferior to 5 Ma), covered nowadays with a thin cover of dry layer. If this is true, there must be some ice not only on the top meters but on hundreds of meters depth. The radars MARSIS and SHARAD respectively aboard Mars Express (in progress) and Mars Reconnaissance Orbiter which is forseen to be launched in 2005 will probably brought additional constraints on these underground reservoirs. References Recent ice-rich deposits formed at high latitude on Mars by sublimation of unstable equatorial ice during low obliquity Levrard, B., Forget, F., Montmessin, F. and Laskar, J., Nature, 28 octobre 2004 Long term evolution and chaotic diffusion of the insolation quantities of Mars. Laskar, J., Correia, A., Gastineau, M., Joutel, F., Levrard, B., Robutel, P.: 2004, Icarus, 170, 343-364 IMAGE CAPTIONS: [Figure 1: http://www.obspm.fr/actual/nouvelle/nov04/mars04-f1.png (46KB)] The cartography of frozen water concentration in the two top meters of the Martian subsurface provided by the Gamma spectrometer of the Odyssey spacecraft. It is the concentration of the element hydrogen which is in fact determined by the gamma spectrum analysis of the radiations sent out by the Martian ground overwhelmed with cosmic rays. The blue and violet zones (high latitudes) indicate a strong concentration of ice, higher than 50% of volume. [Figure 2: http://www.obspm.fr/actual/nouvelle/nov04/mars04-f2.png (37KB)] The ice evolution on Mars over a caracteristic obliquity cycle: the angle between the white arrows and the dotted line denotes the Martian obliquity. At high obliquity, the northern cap becomes unstable and looses a few centimeters of ice each year. This ice is then deposited in equatorial zones. When the obliquity decreases, ice comes back at high latitudes. When the equatorial reservoir disappears, high-latitude ice deposits become unstable too. A fraction sublimates and lays out again towards the poles which contributes to the creation of Martian polar caps, while an other fraction is buried under a protecting dust lag (ASD/IMCCE-CNRS, adapted from Jim Head/Brown University and NASA/JPL). http://www.spaceref.com/news/viewpr.html?pid=15391

Pit chain formation on Mars Strings of depressions dotting the Martian landscape indicate that seismic activity - marsquakes - may still be reshaping the surface of the planet, according to Dr. David Ferrill of Southwest Research Institute in a paper published in the October 10 issue of GSA Today. These pit chains occur along dilational faults, partially filled or open cavities that served as conduits for past groundwater flow. "These faults could now serve as reservoirs for water or ice, making these locations of potentially great interest to the scientific community searching for signs of life on Mars," said Ferrill, a senior program manager at SwRI®. "Astrobiologists consider subsurface aquifer systems high-priority targets for a potential Martian fossil record," said Danielle Wyrick, an SwRI planetary geologist who co-authored the GSA Today article. "Detecting underground water is difficult because current Mars data show only the surface. Pit chains are easy-to-recognize features that give us clues to what's going on below the surface, including prospective groundwater systems." Ferrill, Wyrick and their team reached these conclusions after comparing high-resolution imagery of the surface of Mars with pit chains discovered in Iceland, and conducting laboratory experiments to recreate the processes they believe formed the pit chains. The work was funded internally through an SwRI initiative directed to Mars research. "The pit craters are larger and better preserved on Mars than on Earth because the surface erosion and higher gravity on Earth result in smaller pits that are rapidly erased, sometimes within decades," said Ferrill. In many areas of Mars, pit crater chains appear to be some of the youngest features, postdating drainage channels, faulting and impact craters. Using visible spectrum image data of Mars from the Thermal Emission Imaging System on the Odyssey spacecraft, the team mapped pit crater outlines, surface drainage channels and fault traces. Pit craters can be observed at all stages of formation. The smallest pits have apparently flat floors with surface textures similar to the surrounding topographic surface; the steeper pit walls are smooth. "We deduce that some of these pits are youthful, perhaps even actively forming, because surface subsidence has not destroyed the original surface of in-falling material," explained Ferrill. Laboratory physical analog modeling also supports these observations. Based on analysis of Mars data, scientists simulated slip on a normal fault using unconsolidated dry white or dyed sand to represent Mars surface materials. Constant thickness rigid wooden or aluminum plates, with or without an overlying layer of cohesive powder, represented dilating fissures beneath the sand. Scientists initially placed the plates edge-to-edge and created tabular voids by progressively separating the plates to simulate fault slip. "Our physical models reproduced most pit chain morphologies observed on Mars," said Ferrill. EDITORS: High-resolution images for download are available at http://www.swri.org/press/themis.htm SwRI is an independent, nonprofit, applied research and development organization based in San Antonio, Texas, with more than 2,800 employees and an annual research volume of more than $350 million. http://www.spaceref.com/news/viewpr.html?pid=15398

More Findings About Methane on Mars Summary - (Oct 29, 2004) Researchers from the University of Michigan have recently published their findings about methane in the Martian atmosphere. The methane was discovered using the planetary Fourier spectrometer, which is one of seven instruments on board the ESA's Mars Express spacecraft, which was launched to Mars in 2003. The spectrometer has detected methane at an average of 10 parts per billion by volume; a very small amount compared to 1700 ppbv found here on Earth. Earth-based methane is created almost entirely by life, so the researchers hope that the same process is happening on Mars. Full Story - A University of Michigan scientist is part of a European Space Agency team that has detected methane gas on Mars, and the findings will be published in the online Web journal Science Express today. Sushil Atreya, professor and director of the Planetary Science Laboratory in the College of Engineering says the detection of methane is the clearest indicator of the possibility of life on the Red Planet yet. "Biologically produced methane is one of many possibilities," Atreya said. "Methane is a potential biomarker, if a planet has methane we begin to think of the possibility of life on the planet. On Earth, methane is almost entirely derived from biological sources." Mars resembles Earth more than any other planet in our solar system, and studying its atmosphere gives us a greater understanding of our own. How the methane got to Mars is the big question, and there are several possible sources, Atreya said. The most exciting scenario is that methanogens—microbes that consume the Martian hydrogen or carbon monoxide for energy and exhale methane—dwell in colonies out of sight beneath the surface of the red planet. "These are anaerobic so they don't need oxygen to survive, if they are there," Atreya said. "If they are there, they would be underground." Speculation is tempting, but many more experiments are necessary before drawing any conclusions. "While it's tantalizing to think there are living things on Mars, we aren't in a position to say that is what is causing the methane," Atreya said. A comet could have struck the planet, which would leave methane behind, but that only happens once every 60 million years or so, Atreya said. A more likely scenario is hydrothermal process involving chemical interaction between rock and water in aquifers below the Martian permafrost. The instrument that sniffed out the methane is called a planetary Fourier spectrometer, and it is one of seven instruments on board the Mars Express spacecraft. The spectrometer measures the Sun's infrared light that has been absorbed, emitted and scattered by the molecules in the Martian atmosphere. Every molecule has a unique spectral property—think of it as an infrared fingerprint—including methane. The spectrometer detected an average 10 parts per billion by volume (ppbv) of methane on Mars, a small amount compared to the approximately 1700 ppbv on Earth. The methane gas was distributed unevenly over Mars' surface, which tends to support the theory that an internal, on-site source, rather than a comet, is the source generating the methane, said Atreya. Mars Express launched in June 2003, and it is the first Western European trip to another planet. Original Source: University of Michigan News Release http://www.universetoday.com/am/publish/methane_discovered_mars_findings.html?29102004

5 de noviembre de 2004 El explorador "Spirit" descubre pruebas de la existencia de cenizas volcánicas en Marte Este hallazgo ha tenido lugar sobre una capa estratificada de rocas en las Colinas de Columbia ¿Por qué consumer.es incluye publicidad? El vehículo explorador de la Agencia Espacial de EE.UU. (NASA) "Spirit" ha descubierto pruebas de la existencia de cenizas volcánicas cuyos minerales fueron disueltos por la presencia de agua en el planeta Marte. Según informó la NASA, este hallazgo ha tenido lugar sobre una capa estratificada de rocas diez meses después de que el pequeño vehículo descendiera sobre la superficie del planeta y en las cercanías de la zona conocida como las Colinas de Columbia. "Nuestra hipótesis principal es que estas rocas fueron ceniza volcánica que cayó desde el aire... y que los minerales contenidos en ella fueron disueltos por el agua", dijo Ray Arvidson, científico principal de la misión. Arvidson aclaró que, aunque es una hipótesis, los instrumentos del "Spirit" parecen confirmar que se trata de cenizas volcánicas. "Es importante señalar que acabamos de comenzar a determinar la textura, mineralogía y química de estas rocas estratificadas", declaró. El científico añadió que otra hipótesis sobre su origen se centra en la posibilidad de que esos materiales fueran transportados y depositados por el agua. "En efecto, es posible que la actividad volcánica, el agua y el viento hayan producido las rocas que está examinando el 'Spirit' en estos momentos", apuntó. El vehículo está operando regularmente con sus espectrómetros pese a que está sufriendo problemas en sus ruedas, dijo Jim Erickson, director del proyecto en el Laboratorio de Propulsión a Chorro (JPL) de la NASA, en Pasadena (California). "Estamos tratando de resolverlos, pero esto podría ser un anticipo de lo que va a ocurrir debido a que los componentes mecánicos se han desgastado como consecuencia de la prolongada exploración en Marte", agregó Erickson. http://www.consumer.es/web/es/noticias/educacion_y_ciencia/2004/11/05/111421.php

Mars Methane Boosts Chances for Life By Robert Naeye Could Mars be an abode for life after all? New results from two independent teams suggest that methane gas, a common byproduct of biological activity, is currently being produced on the red planet. Courtesy NASA, J. Bell (Cornell Univ.), and M. Wolff (SSI) November 11, 2004 | Tantalizing new evidence possibly suggestive of current life on Mars has just been reported by two independent teams. The groups, led by Michael J. Mumma (NASA/Goddard Space Flight Center) and Vladimir A. Krasnopolsky (Catholic University of America), have found the spectral signature of methane (CH4) in the Martian atmosphere. Mumma's team found significant enhancements of methane near the equator, while Krasnopolsky's results show a global level of atmospheric methane. The results were presented this week at the American Astronomical Society's Division of Planetary Sciences conference in Louisville, Kentucky. This evidence for methane on Mars has also been corroborated with data gathered by the European Space Agency's Mars Express spacecraft. Methane gas is a potential biomarker because various photochemical and other processes destroy it on Mars. Without being continually replenished, it would disappear from the atmosphere in about 340 years or less. On Earth, microorganisms are by far the dominant source of methane gas. Using NASA's 3-meter Infrared Telescope Facility atop Mauna Kea, Hawaii, Mumma and his colleagues detected methane at a level of 250 parts per billion in equatorial latitudes north of the Hellas impact basin. Further observations conducted with the 8-meter Gemini South telescope in Chile also revealed elevated methane concentrations over Valles Marineris. The team found methane concentrations of 20 to 60 parts per billion at higher latitudes. These methane concentrations are much higher than those previously reported. In both locations, Mumma's group identified two spectral lines due to methane, which minimizes the possibility of a false detection. "I'm shocked by this result; we didn't expect this," says Mumma. "At these two points on Mars the data imply that there were significant methane releases. We could be seeing methane released by methanogens, although we cannot exclude abiotic origins." "This is a very enticing result," adds independent commentator David H. Grinspoon (Southwest Research Institute). "I want to know more about the distribution of methane in the atmosphere so we can better understand where it is being produced and destroyed." Krasnopolsky's group added several spectral lines of methane to improve the detection limit while observing Mars with the 3.6-meter Canada-France-Hawaii Telescope in Hawaii. His team found a global methane level of about 10 parts per billion. Scientists cannot state with certainty the source of the methane. Other possible sources besides microorganisms include volcanic or geothermal activity, or a recent comet impact. But Krasnopolsky points out that the THEMIS instrument on NASA's Mars Odyssey orbiter has found no evidence for volcanic or geothermal hot spots, despite the fact that the instrument was specifically designed to find them. Krasnopolsky also says that there is only a 2 percent chance that a comet impact could have occurred recently enough to account for the observed methane. Krasnopolsky's calculations suggest that Martian organisms would be producing only 270 tons of methane per year, which is 100 million times less than the amount produced by terrestrial organisms. This yields a Martian biomass of at least 20 tons, but possibly higher. "Mars is generally sterile except for small oases," says Krasnopolsky. Grinspoon questions whether a mostly dead planet could sustain isolated pockets of life for long time scales. In a paper published in the 1970s, atmospheric chemist James Lovelock and biologist Lynn Margulis proposed that once life gains a foothold on a planet, it will literally take over the planet by altering its geological and atmospheric cycles. Such a process happened on Earth, where life dominates the surface and even subsurface environments. But even the most optimistic assessments of extant Martian life would agree that this did not happen on Mars. "These results are already stimulating a great deal of theoretical work," says Mumma. "The areas being explored range all the way from geophysics to atmospheric processes." http://skyandtelescope.com/news/article_1389_1.asp

Future Robots May "Hop" Across Mars Summary - (Nov 25, 2004) NASA's Spirit Rover has just completed a long hard slog across difficult Martian terrain to reach the Columbia hills. The short journey of just a couple of kilometres has taken Spirit months. Imagine if it could thoroughly analyze an area and then just pick up and fly somewhere new? NASA has awarded a contract to a proprosal from Pioneer Astronautics, which envisions a vehicle that could land on Mars, refuel with local materials, and then fly hundreds of kilometres to explore; repeating this process over and over again - the Martian Gashopper Aircraft. Full Story - Image credit: Pioneer Astro Part lander, part aircraft, the gashopper (no, not grasshopper) is a unique concept being considered by NASA for future robotic exploration of Mars. Unlike landers, such as the Viking spacecraft, Beagle 2, or the upcoming Phoenix lander which can only examine a few square metres of ground, the gashopper could land, perform scientific analysis and launch itself back into the air to fly hundreds of kilometres to a new location. The gashopper would get its electricity from a large set of solar panels built on top of its wings. It would use this electricity to retrieve carbon dioxide from the Martian atmosphere, and then store it as a liquid inside the aircraft. When enough gas was stored up to make a flight, it would heat up a hot bed of pellets and then pass the CO2 through it. Now hot, the gas would act as a propellant, and allow the gashopper to lift off vertically from the surface of Mars. Once airborne, it could then fire more gas out a rear thruster and begin flying as an airplane, using its large wings for lift and maneuverability. When it was ready to land, the aircraft could slow its airspeed, and then touch down gently as a vertical lander. The proposal comes from the mind of Robert Zubrin, author of The Case for Mars, President of the Mars Society, and the President of Pioneer Astronautics. It's one of 219 research projects selected by NASA for Small Business Research and Development contract awards. Zubrin sees the gashopper not only as a technology for exploring Mars, but as a proof of concept for many engineering challenges that NASA will have to overcome in future missions, both robotic and human. "If we're going to do a sample return mission, we'll want to know how to make propellant for the return journey," explains Zubrin, "and the gashopper will also let us test many liftoffs and landings with hazard avoidance in all kinds of terrain. "The gashopper will be using native carbon dioxide for fuel, so it won't contaminate the soil with hydrocarbons," continues Zubrin. This is important, because spacecraft from Earth using hydrocarbons for fuel could contaminate the landing site with chemicals that could confuse the search for life. "Once the gashopper gets moving, it'll find a pristine Martian surface to explore." The simplest gashopper could actually be quite light, as little as 50 kg (110 pounds). Compare this to the current Mars Exploration Rovers, which both weigh in at 185 kg (380 pounds). Tack on some more weight, and the gashopper could carry a few mini-rovers, like the tiny Sojourner that visited Mars as part of the Pathfinder mission. These could be targeted at the most interesting features based on the gashopper's aerial reconnaissance of the area. Image credit: Pioneer Astro Another advantage of the gashopper is that is could completely ignore terrain. When NASA selected the landing sites for its Mars landers, it purposefully chose locations that were relatively flat, so the rovers could drive at a useful speed. The gashopper could land at the edge of a deep chasm, examine the area, jump down to the bottom and get back out again. It would give scientists unprecedented range and flexibility when searching for evidence of past water or life on Mars. Of course, there's a catch. The limiting feature of the gashopper is the electricity required to pressurize and heat the carbon dioxide propellant. This process consumes a lot of power, and the gashopper would need more than a month using its solar cells to refuel and recharge its batteries before it could take off again. To generate more electricity, NASA could consider using a Radioisotope Thermal Generator, similar to those carried by Cassini, the Viking landers, or the upcoming Mars Science Laboratory (due for launch in 2009). With a more powerful electrical system, the gashopper could lift off every few days, and essentially be able to roam the entire planet of Mars. Zubrin's company, Pioneer Astronautics, has already done a significant amount of testing and research for the concept, and they developed a prototype ballistic gashopper for NASA's Jet Propulsion Lab in 2000. The engine worked well in the lab, and they were able to get a remote-controlled vehicle with a mass of 50 kg to fly in a simulated Martian gravity (using a helium balloon to provide stability). Instead of sitting on one spot, or slowly crawling across the surface of Mars, future robotic explorers to visit the Red Planet may take to the skies and soar. Well... hop, anyway. Written by Fraser Cain http://www.universetoday.com/am/publish/mars_gashopper.html?25112004

Mars Was Once Suitable For Life Summary - (Dec 3, 2004) A series of research papers about past water on Mars have been published in the Journal Science by various scientists involved with the Mars Exploration Rovers. Although the team went public with their discoveries many months ago, these research papers provide the full evidence from the Opportunity rover, and have been exhaustively peer reviewed. They hypothesize that the Meridiani Planum region was once saturated with liquid water for a long enough time to support life. Full Story - Image credit: NASA Scientists have long been tantalized by the question of whether life once existed on Mars. Although present conditions on the planet would seem to be inhospitable to life, the data sent back over the past 10 months by NASA's two exploration rovers, Spirit and Opportunity, showed a world that might once have been warmer and wetter -- perhaps friendly enough to support microbial organisms. Now a Cornell University-led Mars rover science team reports on the historic journey by the rover Opportunity, which is exploring a vast plain, Meridiani Planum, and concludes with this observation: "Liquid water was once present intermittently at the martian surface at Meridiani, and at times it saturated the subsurface. Because liquid water is a key prerequisite for life, we infer that conditions at Meridiani may have been habitable for some period of time in martian history." The article is one of 11 published this week (Dec. 3, 2004) in a special issue of the journal Science, authored by scientists connected with the Mars rover mission, several from Cornell and from the Jet Propulsion Laboratory in Pasadena, Calif., the mission's manager. The issue covers Opportunity through its first 90 days of exploring its landing site of Eagle crater in Meridiani Planum. This was before the rover drove to and entered the large crater dubbed Endurance, from which it is now about to emerge. Steve Squyres, Cornell professor of astronomy and leader of the rovers' Athena science team, is the lead author of the main paper, "The Opportunity Rover's Athena Science Investigation at Meridiani Planum, Mars." In another paper, on which he is also the lead author, Squyres again refers to the geological record at Meridiani Planum as suggesting that conditions were suitable for "biological activity" for a period of time in the history of mars. In the article, "In Situ Evidence for an Ancient Aqueous Environment at Meridiani Planum, Mars," he writes: "We cannot determine whether life was present or even possible in the waters at Meridiani, but it is clear that by the time the sedimentary rocks in Eagle crater were deposited, Mars and Earth had already gone down different environmental paths. Sample return of Meridiani rocks might well provide more certainty regarding whether life developed on Mars." The Mars rover mission is not designed to look for microbial life but to look for evidence of whether conditions were once right for life. As Squyres recently stated, "What we were seeking was rocks that were actually formed in liquid water so that we could read the record in those rocks, not just to say liquid water was on Mars but to learn something about what the environmental conditions were like, would they have been suitable for life and, importantly, do the minerals that were formed have the capability to preserve for long periods of time evidence of former life? That's probably the single most important thing we have found: evidence for minerals at Meridiani that are the kinds of things that are very good at preserving evidence of ancient life for very long periods of time." Opportunity bounced down on Jan. 25, 22 days after its twin, the rover Spirit, landed on the opposite side of Mars in Gusev crater. Last August Science published a special issue on Spirit. "This is the first peer-reviewed presentation of the data from Opportunity," notes Jim Bell, Cornell associate professor of astronomy and the lead scientist for the rovers' Pancam color imaging system. Bell also is prominent in the special issue of Science , including his lead authorship of a paper, "Pancam Multispectral Imaging Results from the Opportunity Rover at Meridiani Planum." When Opportunity landed on the red planet last January, the robot geologist sent back images of its landing site that were unlike any of the other places where earlier lander probes and rovers had gone. Instead of rusty deserts of dusty soil and boulders strewn to the horizon, Opportunity had landed in a relatively small crater in a vast sea of sand nearly devoid of rocks. Fortunately, an intriguing outcrop of bedrock presented itself nearby, which scientists hoped would be a sample of the original crust underneath the layers of dust. The scientists were not disappointed. Scattered among the outcrop rocks were large numbers of small, round mineral deposits that the Athena science team named "blueberries." On Earth, such formations appear when large amounts of water course through rock layers, leaching out the iron-bearing minerals into small spherical rocks and granules. The rovers also detected large amounts of sulfate salt deposits. Enough evidence was collected by Opportunity in the two months it spent examining Eagle crater that the science team felt confident enough to announce in early March that liquid water had flowed over the crater's rocks long ago, possibly for a long time. Following on this, the latest Science articles largely focus on Opportunity's most important scientific and geological accomplishment: the discovery of evidence that liquid water once flowed through the region. Like the coverage given to Spirit in the August issue of Science , the latest edition contains several foldouts with big color panoramas and images from Opportunity's region of exploration. Original Source: Cornell News Release http://www.universetoday.com/am/publish/mars_once_suitable_life.html?3122004

The Martian Methane Surprise Interview with Mike Mumma Volcanoes are another source of methane, although the youngest active source would have to be a few million years ago, and methane without replenishment disappears in 300 years on Mars. Credit:ESA/Mars Express At the recent Division of Planetary Sciences conference in Louisville, Kentucky, Michael Mumma, Director of the Center for Astrobiology at NASA's Goddard Space Flight Center, announced that relatively high levels of methane had been detected on Mars. Methane on Earth is mainly produced by life, but also can be released from volcanoes or tectonic activity. Having methane appear on Mars is something of a mystery, because the planet is not believed to have active volcanism or tectonics. Could the methane be evidence of martian life forms buried underground? In this interview with Astrobiology Magazine editor Leslie Mullen, Mumma explains how they detected the methane, and what it could mean for the chance for life on Mars. -------------------------------------------------------------------------------- Astrobiology Magazine (AM): I remember when a detection of methane on Mars was reported last April. Now you're saying there's a background methane level of 20 to 60 parts per billion (ppb). You've also found spikes of methane on Mars measuring 250 ppb. Mike Mumma (MM): Right. Our results were obtained in March of 2003 using the NASA Infrared Telescope Facility in Hawaii, and in May 2003 using the Gemini South telescope in Chile. But the history of the search for methane on Mars is long and storied. Most of the searches have been done at wavelengths near 3.3 or 7.7 microns, where methane has two strong vibrational bands. Comparing different results is complicated by the fact that many of the early searches were done with globally averaged fields of view, so they were less sensitive to latitudinal and longitudinal variations. In other words, they were insensitive to local sources, because they averaged over everything. AM: So those were studies done from telescopes on Earth, where Mars was viewed as one big pixel? MM: Exactly. Even in the case of Mariner 9's IRIS, the infrared orbiting spectrometer, Bill Maguire from our lab formed a grand average of the spectra regardless of the latitude and longitude, taken at all times of the year, and said, "Here's the spectrum." He estimated the maximum possible abundances for a dozen or so trace constituents, including methane. He found that the average mixing ratio was no more than 20 ppb. "If the methane observation is borne out, maybe there is something living there under the ice." -David Grinspoon Image Credit: NASA That's also what the Mars Express is now claiming to detect, but in their case one of the things that concerns me is the presence of a cloud deck. There was a major dust storm in December of 2003, and it raised the scattering level from the surface to a higher altitude - probably about 20 kilometers above the surface - and this reduced the signature of both water and methane spectral lines of reflected light. Those conditions continued until June of this year. That means that when Mars Express tried to measure methane, they were looking against that background of dust and airborne ice. That would've affected their measurements and made derived abundances appear smaller than they would otherwise be. So far, they have reported data taken in January and February and again in May, and both data sets show the effects of extinction by ice aerosols. But in March 2003, the martian atmosphere was fairly clear. We were able to measure both water vapor and methane in the same spectra at the same time. We compared the water at each position with the amount detected by the TES spectrometer on the orbiting Mars Global Surveyor. AM: To verify that what you were measuring was accurate? MM: Correct. Our water abundances were a factor of three smaller than those of TES. We always have to add a reference level to our spectral measurements to get the true value. I didn't add those numbers in my presentation this year [at the DPS conference]. Instead, I showed the minimum amount we were seeing. Frost dusts the red plains of southern Mars in early spring. Mars's mean annual temperature is -55 °C. Credit: MSSS/JPL/ NASA. AM: Why do you have to add reference values to your readings? MM: The reason we do it that way is because the telescope is looking through a column of Earth air. The photons collected from Mars traverse the same terrestrial column of air, regardless of their position along the spectrometer entrance slit. By choosing one spectrum as a reference, and subtracting it from every other measured spectrum, we can cancel these terrestrial atmospheric features perfectly. In that way, we can isolate the Mars spectrum. So we did this to find the methane abundance, and discovered that the methane shows a significant enhancement at the equatorial region. At high latitudes in the north and south, there is much less methane. It's 20 to 60 ppb in the north, and even lower in the south. But it was more than 250 ppb at the equator. AM: Does the mixture of methane in the atmosphere naturally change as you rise in altitude, or as the temperature changes? MM: No, not really. On Mars, the mixing ratio of water vapor undoubtedly changes greatly with altitude, because it condenses. But methane does not condense at martian temperatures, so it must be uniformly mixed with altitude. Now, there are caveats. There could be processes on Mars that destroy methane. If airborne dust coated with oxidants is lofted into the atmosphere, then methane could collide with that dust and be converted to other hydrocarbons, such as methanol or formaldehyde. A new study by Sushil Atreya suggests that hydrogen peroxide created by dust devils could act to scrub methane out of the atmosphere. But even if methane is being destroyed in this way, it doesn't affect our measurement. Mars airplane design Credit: NASA AM: Right, because there would be even more methane on Mars than the high level that you found. MM: Exactly. AM: But if methane is being actively destroyed, then doesn't that suggest that the methane you found is very current? MM: It is definitely current. AM: I heard that methane has a lifetime of about 300 years, which is very current astronomically speaking, but I meant "current" as in "being released right now." MM: We think it is being released right now. We think that's why we're seeing this intense enhancement at equatorial latitudes. Such an intense release will, over time, naturally diffuse outward in the atmosphere and be transported elsewhere, spreading around the planet and to the poles. AM: So your reading of 250 ppb in the equatorial region, that was confined to a small area? Extreme Life Briefing Hottest: 235 F (113 C) Pyrolobus fumarii (Volcano Island, Italy) Coldest: 5 F (-15 C) Cryptoendoliths (Antarctica) Highest Radiation: (5 MRad, or 5000x what kills humans) Deinococcus radiodurans Deepest: 3.2 km underground Acid: pH 0.0 (most life is at least factor of 100,000 less acidic) pH 5-8 Basic: pH ~13(most life is at least factor of 1000 less basic) pH 5-8 Longest in space: 6 years Bacillus subtilis (NASA satellite) High Pressure (1200 times atmospheric) Saltiest: 30% salt, or 9 times human blood saltiness. Haloarcula Smallest: <0.1 micron or 500 fit across a human hair width (picoplankton) Credit: USGS MM: Yes, it was about minus 10 degrees south to 10 degrees north. AM: And what's the topography of this region? MM: It's a transition region from the highlands to a plain - Syrtis Major Planitia. There are many scarps, or cliff faces, where the topography changes drastically. That's interesting because the other region where we showed evidence of enhanced methane was over the deep rift valley Vallis Marineris - another region with steep, high cliffs. One working model is that methane is diffusing under the permafrost and emerging at the cliff face. You wouldn't see it emerge unless there was a cliff face, or if there were fissures or ancient volcanic pipes reaching down below the permafrost. AM: On Earth, a lot of methane has an organic origin. MM: Right. Methane on Mars could be produced by non-biological methods or by biological ones. We don't yet have the evidence to support one or the other. One possibility is drawn from Earth, where one tectonic plate is subducted under another. The subducting plate carries with it carbon dioxide, water, organic material, and so forth. When it reaches the hot magmatic region, that material reacts with olivine and converts it to a different mineral - magnetite - releasing hydrogen in the process. That hydrogen reacts with carbon to form methane, which then percolates upwards and is released. That process requires active tectonics, and we don't see any evidence for that on Mars at present. But we can test this idea by searching for other higher order hydrocarbons, and by measuring the D/H ratio - the ratio of deuterium to hydrogen - in methane. A tectonic process would most likely be consuming juvenile water stored from a time when Mars was young, and in that case it should have a lower ratio of deuterium to hydrogen than present-day water. So if methane on Mars has a low D/H ratio, that would suggest it is geothermally produced, or at least produced from the deep reservoir. Another possibility is active biology. Here you have a choice as to whether the bio-release is at the surface layer or deep below the permafrost. If it's below the permafrost, and if the permafrost is an impervious cap, then you should have sideways diffusion, with the methane later being released at the cliff faces. You could have bioforms consuming carbon dioxide and water that is relatively younger than the deep stuff, and then you'd expect to see a higher deuterium abundance. You would also expect to see depleted carbon-13, heavy carbon, in the methane released by bioforms. AM: Are these predictions based on how methanogens behave on Earth? MM: That's right. They'd have to be similar in nature, and of course we have no idea whether that would be true or not. Members of the University of Rhode Island's NASA astrobiology team have shown that methane and ethane are produced in similar abundance in cold deep-sea sediments. In that environment, the gases are probably produced by life. That's potentially important, because if life forms on Mars are similar, ethane should be released along with methane. So I'm suggesting a chemical search, using ground-based telescopes, to look for other hydrocarbons on Mars. Whether detected or not, we can fold the results into the model to constrain the possibilities. The measurement of isotopic ratios, like carbon-13 or carbon-12, probably can't be done from the ground with the accuracy required. That measurement would require an orbiter around Mars, or an airplane flying over the vents. So if the present results are upheld, they could define the course of Mars exploration for years to come. http://www.astrobio.net/news/article1332.html

La NASA confirma la existencia de agua en Marte Sin embargo, señalaron que los trabajos realizados por sus vehículos de exploración "Spirit" y "Opportunity" no han logrado establecer la existencia de vida en el planeta rojo. (AP) Por Orlando J.Lizama EFE washington.- El planeta Marte tuvo agua en abundancia en su pasado remoto y un ambiente propicio para el desarrollo de la vida, anunciaron científicos del Laboratorio de Propulsión a Chorro (JPL) de la agencia espacial estadounidense. "Hubo un momento en el que Marte estuvo empapado de agua", dijo ED Weiler, uno de los científicos encargados de la misión de los todoterreno que se posaron sobre la superficie del planeta con la misión principal de verificar la existencia de agua. "La pregunta ahora es si hubo vida y si hay vida ahora en Marte", agregó Weiler, al anunciar uno de los mayores logros de la exploración científica de EEUU en el espacio. El "Spirit" llegó a Marte el 3 de enero hasta las cercanías del cráter Gusev y 21 días después lo hizo el "Opportunity" en el otro extremo del planeta. Según los científicos de la agencia espacial de EU (NASA), los vehículos tienen una vida útil de alrededor de 90 días en la superficie marciana. Al cabo de ese tiempo, el polvo marciano comenzará a cubrir los paneles que proporcionan la energía para el funcionamiento de todos sus instrumentos. A un costo de 820 millones de dólares, "la NASA puso en marcha esta misión específicamente para determinar si al menos en parte del planeta hubo un ambiente húmedo que pudo haber albergado algún tipo de vida", dijo James Garvin, director del equipo científico de la NASA. "Hoy tenemos poderosos fundamentos para dar una respuesta positiva: Sí", señaló emocionado el científico. Steve Squyres, principal investigador y director de las tareas asignadas a los instrumentos de ambos vehículos, precisó que la mayor parte de esos fundamentos fueron encontrados en las rocas analizadas por el "Opportunity". Ese vehículo explorador descendió el 24 de enero sobre un cráter cuyas rocas y composición indicaron que allí fluyó el agua en un momento y que ésta cambió la composición química y la estructura geológica, indicó. Squyres manifestó que el vehículo explorador realizó un análisis específico en una roca llamada "El capitán" y que los científicos hallaron allí una alta concentración de magnesio, hierro y de sales sulfatadas. El "Opportunity", que descendió en un cráter en medio de la llanura Meridiani Planum, cerca del Ecuador marciano, también detectó la existencia de una sal, identificada como "jarosita", que es rica en hierro y azufre. Según los científicos, en la Tierra esos depósitos minerales se formaron ante la presencia de agua y el hecho de que se haya encontrado "jarosita" sugiere un ambiente rico en ácido o de aguas termales. Según habían informado previamente los científicos del JPL, el espectrómetro del "Opportunity" también había detectado hematita, una sal que en la Tierra sólo se forma ante una alta presencia de agua en su forma líquida y con alto contenido de oxígeno. Además, las fotografías enviadas por ambos vehículos espaciales revelan que las rocas examinadas por ellos sufrieron una erosión que sólo puede ser explicada por la presencia de agua, destacó Squyres. Estudios adicionales determinarán próximamente si las rocas examinadas formaban el lecho de un lago salado o de un mar. En un esfuerzo por no dejar dudas de que la existencia de agua en Marte fue confirmada una y otra vez por los científicos, el geólogo John Grotzinger señaló que también se extrajeron pruebas de observaciones visuales. Estas incluyeron la presencia en "El capitán" de pequeños huecos y esferas, así como la estructura estratificada de las rocas, manifestó. EFE http://www.ocvive.com/noticias/newswires/0303_noti_wr_marte_agua.shtml